Directory
All calculators
365 calculators organized by topic. Every calculator shows the formula, worked examples, and assumptions.
Browse by topical hub
Finance Calculators
Loans, mortgages, investing, tax and business maths in one connected hub.
110 tools
Health Calculators
Body composition, nutrition, training load and clinical ratios, semantically linked.
53 tools
Math Calculators
Algebra, geometry, statistics, probability and number tools with formulas shown.
85 tools
Date & Time Calculators
Durations, business days, countdowns and time-unit arithmetic.
29 tools
Construction Calculators
Material quantities, coverage and waste factors for building projects.
23 tools
Unit Conversion Tools
Length, area, volume, weight, temperature, energy, pressure, speed and data units.
31 tools
Everyday & Utility Calculators
Vehicles, energy bills, weather, shopping and other practical tools.
34 tools
Financial
Mortgage Calculator
Estimate your monthly mortgage payment, total interest, and payoff schedule.
Auto Loan Calculator
Monthly car payment from price, down payment, trade-in, and sales tax.
Loan Calculator
Compute the fixed monthly payment on any amortizing loan.
Personal Loan Calculator
Monthly payment and total cost for a personal loan.
Business Loan Calculator
Payment and interest cost for a business term loan.
Student Loan Calculator
Estimate monthly payment and total interest on a student loan.
Boat Loan Calculator
Estimate monthly payments on a boat loan.
RV Loan Calculator
Monthly payment for a recreational vehicle loan.
Lease Calculator
Estimate the monthly payment for a vehicle lease.
Amortization Calculator
Year-by-year principal, interest, and remaining balance schedule.
APR Calculator
True annual percentage rate on a loan with fees.
Refinance Calculator
Compare current vs. refinanced mortgage payments and break-even.
Mortgage Payoff Calculator
See how extra monthly payments shorten your mortgage.
FHA Loan Calculator
Estimate FHA mortgage payment with MIP.
VA Loan Calculator
VA loan payment with funding fee.
Compound Interest Calculator
Project the future value of savings with compounding and periodic contributions.
Simple Interest Calculator
Interest earned or owed under simple (non-compounding) interest.
Investment Calculator
Project future value of a lump sum plus regular contributions.
Retirement Calculator
Project retirement balance and check the 4% withdrawal rule.
Roth IRA Calculator
Project tax-free Roth IRA balance at retirement.
401(k) Calculator
Project a 401(k) balance including employer match.
CD Calculator
Certificate of deposit interest and maturity value.
Savings Calculator
Monthly deposit needed to reach a savings goal by a target date.
ROI Calculator
Return on investment as a percentage plus annualized rate.
Bond Calculator
Price a bond from face value, coupon, yield, and maturity.
Annuity Calculator
Future value of an ordinary annuity.
529 Plan Calculator
Project 529 college savings growth.
Social Security Calculator
Estimate monthly Social Security retirement benefit.
College Cost Calculator
Projected 4-year college cost with tuition inflation.
Inflation Calculator
Convert a dollar amount across years at an assumed inflation rate.
Salary Calculator
Convert between hourly, weekly, monthly, and annual pay.
Take-Home Pay Calculator
Estimate net pay after federal, FICA, and state deductions.
Income Tax Calculator
Estimated US federal income tax using 2024 brackets.
Sales Tax Calculator
Add or reverse sales tax from a pre- or post-tax price.
VAT Calculator
Add or reverse Value Added Tax from net or gross price.
Property Tax Calculator
Estimate annual property tax from assessed value and mill rate.
Estate Tax Calculator
Estimate federal estate tax (2024).
Discount Calculator
Sale price and savings from a list price and discount percent.
Margin Calculator
Profit margin, markup, and selling price from cost and revenue.
Tip Calculator
Split a restaurant bill with tax and tip across any number of people.
Depreciation Calculator
Straight-line depreciation of an asset over its useful life.
Currency Calculator
Convert between currencies using a manual exchange rate.
Debt Payoff Calculator
Months to pay off a debt at a fixed monthly payment.
Debt Consolidation Calculator
See if consolidating debts into one loan lowers your payment.
Credit Card Payoff Calculator
Months to pay off a credit card balance at a fixed monthly payment.
Budget Calculator
50/30/20 monthly budget split from take-home pay.
Down Payment Calculator
Down payment amount and PMI implications from home price and percent.
Rent vs Buy Calculator
Compare total costs of renting versus buying over a horizon.
Home Equity Calculator
Estimate available home equity and HELOC borrowing power.
Rental Property Calculator
Cash flow, cap rate, and cash-on-cash return for a rental.
Real Estate Calculator
Total monthly cost of home ownership (PITI + HOA).
Real Estate Investment Calculator
Cash flow and returns on an income property.
Net Worth Calculator
Assets minus liabilities, at a glance.
Break-Even Calculator
Units and revenue needed to cover costs.
Payback Period Calculator
How long an investment takes to repay itself.
Cap Rate Calculator
Capitalization rate on a rental property.
Dividend Calculator
Dividend income, yield and reinvested growth.
Overtime Pay Calculator
Weekly pay with overtime and double-time hours.
Commission Calculator
Commission earned on sales, with base pay.
Savings Goal Calculator
Monthly amount needed to hit a savings target.
Burn Rate & Runway Calculator
Monthly cash burn and months of runway remaining.
Business Valuation Calculator
Estimate business value using an earnings multiple (SDE/EBITDA).
Cash Flow Calculator
Net cash flow from operating, investing and financing activities.
Churn Revenue Calculator
Revenue lost to customer churn and net revenue retention.
Cost Per Acquisition Calculator
Cost per lead and per converted customer across a funnel.
Customer Acquisition Cost Calculator
CAC from total sales & marketing spend and new customers won.
Customer Lifetime Value Calculator
CLV from average order value, purchase frequency and margin.
EBITDA Calculator
Earnings before interest, taxes, depreciation & amortization.
Freelance Rate Calculator
Hourly rate needed to hit a target income as a freelancer.
Gross Profit Calculator
Gross profit and gross margin from revenue and COGS.
Gross to Net Pay Calculator
Estimate take-home pay after taxes and deductions.
Hourly to Salary Calculator
Convert an hourly wage into annual, monthly and weekly salary.
Inventory Turnover Calculator
How many times inventory is sold and replaced per year.
Invoice Discount Calculator
Early-payment discount savings (e.g. 2/10 net 30 terms).
Invoice Late Fee Calculator
Late payment fee and total amount owed on an overdue invoice.
IRR Calculator
Approximate internal rate of return for level annual cash flows.
Equipment Lease vs Buy Calculator
Compare total cost of leasing vs buying business equipment.
Loan Extra Payment Calculator
Interest and time saved by paying extra on a loan (EMI).
Margin vs Markup Calculator
Convert between profit margin and markup percentages.
Markup Calculator
Selling price from cost and desired markup percentage.
NPV (Net Present Value) Calculator
Discounted cash flow value of an investment over 5 years.
Payroll Tax Calculator
Employer and employee FICA-style payroll tax estimate (US).
Sales Forecast Calculator
Project future sales using a constant growth rate.
Self-Employment Tax Calculator
SE tax on net self-employment earnings (US 15.3% rule).
Working Capital Calculator
Working capital and current ratio from balance sheet items.
Allowance / Pocket Money Calculator
Weekly allowance based on age, chores and savings split.
Annuity Payout Calculator
Periodic payment a lump sum can sustain.
Bond Yield to Maturity Calculator
Approximate YTM for a coupon bond.
CAGR Calculator
Compound annual growth rate between two values.
Capital Gains Tax Calculator
Estimated tax owed on short- or long-term gains.
Cost Basis / Average Down Calculator
Blended average cost after adding to a position.
Crypto Profit Calculator
Profit/loss on a cryptocurrency trade, after fees.
Dollar Cost Averaging Calculator
Shares and average cost from periodic fixed investments.
Dividend Reinvestment (DRIP) Calculator
Portfolio growth with dividends reinvested vs taken as cash.
Emergency Fund Calculator
Target cash cushion based on monthly expenses.
Expense Ratio Impact Calculator
Long-term cost of fund fees on portfolio growth.
FIRE Number Calculator
Portfolio size needed for financial independence.
Future Value Calculator
What a lump sum plus contributions grows to.
Inheritance Split Calculator
Divide an estate among heirs by equal or custom shares.
Margin Trading Calculator
Leveraged return and margin call price.
Mining Profitability Calculator
Daily/monthly profit from crypto mining.
Options Break-Even Calculator
Stock price needed to break even on a call or put.
Portfolio Rebalance Calculator
Trades needed to return to target stock/bond allocation.
Present Value Calculator
What a future sum is worth today.
Rule of 72 Calculator
Quick estimate of years to double your money.
Staking Rewards Calculator
Compounded staking income over time.
Stock Profit Calculator
Profit or loss on a stock trade, after fees.
Marginal vs Effective Tax Rate Calculator
US federal tax owed, marginal bracket, and effective rate.
Tithing / Zakat Calculator
Charitable giving amount from income or wealth.
Treasury Bill Calculator
Discount yield and investment return on a T-bill.
Health
BMI Calculator
Body Mass Index from height and weight, in metric or US units.
BMR Calculator
Basal Metabolic Rate from the Mifflin–St Jeor equation.
TDEE Calculator
Total Daily Energy Expenditure from BMR and activity level.
Calorie Calculator
Daily calorie needs for maintenance, cutting, and bulking.
Macro Calculator
Protein, carbs, and fat targets from calorie intake.
Protein Calculator
Daily protein target in grams based on body weight and activity.
Fat Intake Calculator
Recommended daily fat grams from calorie target.
Carbohydrate Calculator
Daily carb grams from your calorie target.
Sugar Intake Calculator
AHA-recommended daily added sugar limit.
Ideal Weight Calculator
Ideal body weight range from height and sex using multiple formulas.
Overweight Calculator
How many pounds you are above a healthy BMI range.
Body Fat Calculator
Estimate body fat percent from body measurements (US Navy method).
Lean Body Mass Calculator
Estimate lean body mass using the Boer formula.
Target Heart Rate Calculator
Training zones from age using the Karvonen method.
Heart Rate Zones Calculator
Training zones from your max heart rate.
One Rep Max Calculator
Estimate 1RM from a submaximal lift (Epley formula).
Water Intake Calculator
Daily water needs based on weight and activity.
Pace Calculator
Running pace, time, or distance — solve for any of the three.
Pregnancy Due Date Calculator
Estimated due date from last menstrual period (Naegele's rule).
Ovulation Calculator
Estimate ovulation and fertile window from cycle length.
Pregnancy Weight Gain Calculator
Recommended pregnancy weight gain range.
BAC Calculator
Estimated blood alcohol content by the Widmark formula.
Calories Burned Calculator
Energy burned by activity using MET values.
Steps to Calories Calculator
Convert daily step count into calories and distance.
Body Surface Area Calculator
BSA by Du Bois, Mosteller and Haycock formulas.
Waist to Hip Ratio Calculator
WHR and the health risk band it falls in.
Child Height Predictor
Estimate adult height from parents' heights.
Smoking Cost Calculator
Lifetime money spent on cigarettes.
A1C to Average Glucose Calculator
Convert HbA1c percentage to estimated average glucose.
Army/Navy Body Fat Calculator
Body fat percentage using the U.S. military circumference method.
TDEE for Athletes Calculator
Total daily energy expenditure adjusted for training volume.
Blood Pressure Category Calculator
Classify blood pressure reading using AHA categories.
Caffeine Half-Life Calculator
How much caffeine remains in your system over time.
Calorie Deficit Calculator
Daily deficit needed to lose weight at your target rate.
Child BMI Percentile Calculator
Approximate BMI percentile for children and teens.
Cholesterol Ratio Calculator
Total cholesterol to HDL ratio and cardiovascular risk indicator.
Creatinine Clearance Calculator
Cockcroft-Gault estimate of creatinine clearance.
Cycling Power/Speed Calculator
Estimate cycling speed from power output.
eGFR Calculator
Estimated glomerular filtration rate (kidney function) using CKD-EPI.
FFMI Calculator
Fat-Free Mass Index to gauge muscularity.
Goal Weight Date Calculator
The calendar date you'll likely hit your goal weight.
Heart Rate Recovery Calculator
Gauge cardiovascular fitness from post-exercise heart rate drop.
Marathon Time Predictor
Predict your marathon finish from a recent race result.
Max Heart Rate Calculator
Estimated maximum heart rate using multiple formulas.
Menstrual Cycle Length Calculator
Average cycle length and predicted next period from recent cycles.
Running Pace Splits Calculator
Even-pace splits for any race distance.
Sleep Cycle Bedtime Calculator
Best bedtimes or wake times based on 90-minute sleep cycles.
Swimming Pace Calculator
Pace per 100m/yards and projected race times.
Treadmill Incline Calories Calculator
Calories burned adjusting for treadmill incline.
VO2 Max Calculator
Estimate aerobic fitness from a timed run.
Waist-to-Height Ratio Calculator
A simple screen for central obesity risk.
Walking Calories Calculator
Calories burned walking at a given speed and duration.
Weight Loss Timeline Calculator
Estimate how long it will take to reach your goal weight.
Math
Percentage Calculator
Percent of a number, percent change, and reverse percent problems.
Percent Error Calculator
Absolute and percent error between a measured and accepted value.
Fraction Calculator
Add, subtract, multiply, or divide two fractions with simplification.
GPA Calculator
Weighted grade-point average from letter grades and credit hours.
CGPA Calculator
Cumulative GPA across multiple semesters, weighted by credits.
High School GPA Calculator
Weighted high school GPA with Regular, Honors, and AP/IB boosts.
GPA to Percentage Calculator
Convert a 4.0-scale GPA (or 10-scale CGPA) into a percentage.
Percentage to GPA Calculator
Convert a percentage grade into a 4.0-scale GPA or 10-point CGPA.
Grade Calculator
Final exam score needed to reach a target course grade.
Test Score Calculator
Convert correct answers into percentage, letter grade, and curved score.
Class Rank Percentile Calculator
Convert a class rank into a top-N% percentile.
Statistics Calculator
Mean, median, mode, range, variance, and standard deviation.
Probability Calculator
P(A ∪ B), P(A ∩ B), and conditional probability from two events.
Permutation and Combination Calculator
Count ordered permutations P(n,r) and unordered combinations C(n,r).
GCF and LCM Calculator
Greatest common factor and least common multiple of two integers.
Prime Number Calculator
Check primality and list all prime factors.
Exponent Calculator
Compute any base raised to any power, including fractional and negative.
Log Calculator
Logarithm in any base, plus natural log and log base 10.
Root Calculator
nth root of a number.
Quadratic Formula Calculator
Solve ax² + bx + c = 0 for real or complex roots.
Slope Calculator
Slope and equation of a line from two points.
Distance Formula Calculator
Euclidean distance between two 2D or 3D points.
Circle Calculator
Area, circumference, and diameter from a circle radius.
Triangle Calculator
Area, perimeter, and heights from three sides (Heron's formula).
Right Triangle Calculator
Hypotenuse and angles from the two legs.
Pythagorean Theorem Calculator
Find the missing side of a right triangle: a² + b² = c².
Half-Life Calculator
Amount remaining after time for exponential decay.
Scientific Notation Calculator
Convert a number to and from scientific notation.
Matrix Calculator (2×2)
Determinant and inverse of a 2×2 matrix.
Ratio Calculator
Solve A:B = C:D for the missing term.
Rounding Calculator
Round to decimal places, integer, tens, hundreds, thousands.
Binary / Hex Converter
Convert between decimal, binary, octal, and hexadecimal.
Random Number Generator
Uniformly random integers or decimals in any range.
Percentage Change Calculator
Increase or decrease between two numbers.
Average Calculator
Mean of a list of numbers, plus sum and count.
Combination Calculator
nCr combinations and nPr permutations.
Factorial Calculator
n! for whole numbers, with digit count.
Sequence Calculator
Arithmetic and geometric sequence terms and sums.
Significant Figures Calculator
Round a number to a chosen number of sig figs.
Box Surface Area Calculator
Surface area and volume of a rectangular box.
Complex Number Arithmetic Calculator
Add, subtract, multiply and divide complex numbers.
Cone Calculator
Volume and surface area of a right circular cone.
Coordinate Reflection & Rotation Calculator
Reflect or rotate a 2D point.
3D Cross Product Calculator
Cross product and magnitude of two 3D vectors.
Cube Calculator
Volume, surface area and diagonal of a cube.
Cubic Equation Root Calculator
Real root(s) of ax³ + bx² + cx + d = 0.
Cylinder Calculator
Volume and surface area of a cylinder.
Dot Product Calculator
Dot product and angle between two 2D vectors.
Ellipse Calculator
Area and approximate perimeter of an ellipse.
Hypotenuse Length Calculator
Find the hypotenuse of a right triangle.
Law of Cosines Calculator
Find a side from two sides and the included angle.
Law of Sines Calculator
Find a missing side or angle using the law of sines.
Linear Equation Solver
Solve ax + b = c for x.
Midpoint Calculator
Midpoint between two coordinate points.
Parallelogram Area Calculator
Area of a parallelogram from base and height.
Polygon Angles Calculator
Interior and exterior angles of a regular polygon.
Pyramid Volume Calculator
Volume of a pyramid with a square base.
Rectangle Area Calculator
Area and perimeter of a rectangle.
Regular Polygon Area Calculator
Area and perimeter of a regular polygon.
Sector & Arc Length Calculator
Arc length and sector area from radius and angle.
Similar Triangles Scale Calculator
Scale factor and missing side of similar triangles.
Sphere Calculator
Volume and surface area of a sphere.
System of Two Equations Calculator
Solve a1x + b1y = c1 and a2x + b2y = c2.
Trapezoid Area Calculator
Area of a trapezoid from parallel sides and height.
Vector Addition & Magnitude Calculator
Add two 2D vectors and find the resultant magnitude.
Binomial Probability Calculator
Probability of exactly k successes in n trials.
Coin Flip Probability Calculator
Chance of getting exactly k heads in n flips.
Confidence Interval Calculator
Confidence interval for a sample mean.
Correlation Coefficient Calculator
Pearson's r between two paired data sets.
Dice Probability Calculator
Odds of a target sum when rolling multiple dice.
Divisors & LCM Chain Calculator
All divisors, GCD and LCM across up to four numbers.
Expected Value Calculator
Average outcome of a probabilistic bet or event, over the long run.
Linear Regression Calculator
Best-fit line (y = mx + b) through paired data.
Margin of Error Calculator
Margin of error for a survey proportion.
Mean, Median & Mode Calculator
Central tendency of a data set: mean, median and mode.
Modulo Calculator
Remainder of a division (a mod n).
Normal Distribution Probability Calculator
Probability that X falls below, above or between values.
Number Base Converter
Convert a number between binary, octal, decimal and hex.
Number to Words Converter
Spell out a number in English words.
Odds Converter
Convert between probability, decimal odds and fractional odds.
Percentile Calculator
Find the percentile rank of a value in a data set.
Poisson Distribution Calculator
Probability of k events given an average rate λ.
Proportion Solver
Solve for the missing value in a/b = c/d.
Quartiles & IQR Calculator
Q1, median, Q3 and interquartile range with outlier bounds.
Roman Numeral Converter
Convert numbers to Roman numerals and back.
Sample Size Calculator
Minimum sample size needed for a survey.
Standard Deviation Calculator
Sample and population standard deviation and variance.
Variance Calculator
Sample and population variance of a data set.
Weighted Average Calculator
Average of values weighted by importance.
Z-Score Calculator
How many standard deviations a value is from the mean.
Date & Time
Age Calculator
Exact age in years, months, and days between two dates.
Date Calculator
Add or subtract days from a date, or find days between two dates.
Hours Calculator
Hours and minutes between a start and end time, minus break.
Time Calculator
Add or subtract hours, minutes, and seconds.
Add or Subtract Days Calculator
Shift a date forward or backward by a number of days.
Age in Days and Hours Calculator
Exact age expressed in days, hours and minutes.
Business Days Calculator
Count weekdays (Mon–Fri) between two dates.
Chinese Zodiac Calculator
Chinese zodiac animal and element from a birth year.
Countdown to Date Calculator
Time remaining until a future date and time.
Day of the Week Finder
Find which day of the week any date falls on.
Days Between Dates Calculator
Exact number of days separating two calendar dates.
Decimal Hours Converter
Convert between HH:MM time and decimal hours.
Elapsed Time Calculator
Duration between two clock times on the same day.
Generation Finder Calculator
Which named generation a birth year belongs to.
Leap Year Calculator
Check whether a year is a leap year.
Meeting Time Planner
Local meeting time for a remote participant given a UTC offset gap.
Military Time Converter
Convert between 12-hour and 24-hour clock time.
Months Between Dates Calculator
Calendar months and days separating two dates.
Project Deadline Calculator
Deadline date given a start date and business-day duration.
Fiscal Quarter Finder
Which calendar or fiscal quarter a date falls in.
Retirement Date Calculator
Estimated calendar date you reach retirement age.
School Days Remaining Calculator
Weekday school days left until the last day of term.
Weekly Time Card Calculator
Total weekly hours from five daily clock-in/out pairs.
Time Duration Adder
Add two durations given in hours, minutes and seconds.
Time Zone Difference Calculator
Hour difference between two fixed UTC offsets.
Week Number Calculator
ISO 8601 week number for a given date.
Weeks Between Dates Calculator
Full weeks and remaining days between two dates.
Workdays From a Date Calculator
Find the date N business days after a start date.
Zodiac Sign Calculator
Western astrological sign from a birth date.
Other
Square Footage Calculator
Area of rectangular rooms, plus optional material cost.
Volume Calculator
Volume of common 3D shapes: box, cylinder, sphere, cone.
Concrete Calculator
Cubic yards of concrete for a slab.
Tile Calculator
Number of tiles for a floor or wall area.
Roofing Calculator
Shingle squares needed for a roof.
Mulch Calculator
Cubic yards of mulch for a garden bed.
Gravel Calculator
Tons of gravel for a driveway or path.
Stair Calculator
Rise, run, and stringer length for a staircase.
BTU Calculator
AC or heater BTU needed to cool or heat a room.
Sleep Calculator
Best bedtimes based on 90-minute sleep cycles.
Fuel Cost Calculator
Trip fuel cost from distance, fuel economy, and price per gallon.
Gas Mileage Calculator
Compute MPG from miles and gallons.
Speed Calculator
Solve for speed, distance, or time.
Wind Chill Calculator
Perceived temperature from air temp and wind.
Heat Index Calculator
Apparent temperature from heat and humidity.
Password Strength Calculator
Estimate password entropy in bits.
Paint Calculator
Gallons of paint needed for a room.
Fence Calculator
Posts, rails and panels for a fence run.
Drywall Calculator
Sheets, screws, mud and tape for a room.
Electricity Cost Calculator
Cost of running an appliance per day, month and year.
Unit Price Calculator
Compare two package sizes to find the better deal.
Temperature Converter
Convert between Celsius, Fahrenheit, and Kelvin.
Length Converter
Convert between mm, cm, m, km, in, ft, yd, and mi.
Weight Converter
Convert between mg, g, kg, ton, oz, lb, and stone.
Speed Converter
Convert between mph, km/h, m/s, knots, and ft/s.
Area Converter
Convert between sq ft, sq m, acres, hectares, and sq km.
Volume Converter
Convert between gallons, liters, cups, quarts, and milliliters.
Time Converter
Convert between seconds, minutes, hours, days, weeks, and years.
Energy Converter
Convert between energy units.
Power Converter
Convert between power units.
Pressure Converter
Convert between pressure units.
Data Storage Converter
Convert between digital storage units.
Angle Converter
Convert degrees, radians, and gradians.
AC/Window Unit Sizing Calculator
BTU cooling capacity needed for a room.
Asphalt Calculator
Asphalt tonnage needed for a driveway or lot.
Battery Backup Runtime Calculator
How long a battery backup will power a load.
Concrete Block Wall Calculator
CMU blocks and mortar bags for a wall.
Brick Calculator
Number of bricks needed for a wall.
Car Lease Mileage Overage Calculator
Estimated overage fee for exceeding lease mileage.
Carpet Calculator
Carpet area and cost including padding.
Deck Boards Calculator
Number of deck boards needed for a given area.
EV Charging Cost Calculator
Cost to charge an electric vehicle and per-mile cost.
Flooring Calculator
Flooring material needed with waste allowance.
Fuel Savings Comparison Calculator
Compare fuel costs between two vehicles over time.
Generator Sizing Calculator
Generator wattage needed to run selected appliances.
Horsepower & Torque Calculator
Convert between engine horsepower, torque and RPM.
Insulation R-Value Calculator
Combined R-value of layered insulation materials.
Lumber Board Feet Calculator
Board feet and cost for dimensional lumber.
Plywood Sheets Calculator
Number of 4×8 plywood sheets needed for an area.
Pool Chemicals Calculator
Chlorine and pH adjuster dosing by pool volume.
Pool Volume Calculator
Gallons in a rectangular pool.
Rebar Calculator
Rebar pieces and length for a slab grid.
Siding Calculator
Siding squares and cost for exterior walls.
Solar Panel Sizing Calculator
Number of solar panels needed to cover energy use.
Sprinkler Coverage Calculator
Number of sprinkler heads needed for a lawn area.
Tire Size Comparison Calculator
Compare diameter and speedometer effect of two tire sizes.
Topsoil Calculator
Cubic yards of topsoil needed for an area.
Wallpaper Calculator
Number of wallpaper rolls needed for a room.
Altitude Pressure Calculator
Atmospheric pressure at a given altitude (barometric formula).
Clothing Size Converter
Convert women's clothing sizes between US, UK, EU.
Cooking Measurement Converter
Convert between cups, tablespoons, teaspoons and millilitres.
Density Converter
Convert density between kg/m³, g/cm³ and lb/ft³.
Dew Point Calculator
Dew point temperature from air temperature and humidity.
Flow Rate Converter
Convert flow rate between L/min, GPM, m³/h and CFM.
Force Converter
Convert force between Newtons, pounds-force and kgf.
Frequency Converter
Convert frequency between Hz, kHz, MHz, GHz and RPM.
Fuel Economy Converter
Convert MPG (US/UK) to L/100km and vice versa.
Absolute Humidity Calculator
Convert relative humidity to absolute humidity (g/m³).
Ideal Gas Law Calculator
Solve PV = nRT for pressure, volume, moles or temperature.
Luminance Converter
Convert luminous intensity between lux, lumens and foot-candles.
Molarity Calculator
Solution molarity from mass, molar mass and volume.
Ohm's Law Calculator
Solve for voltage, current, resistance or power.
Oven Temperature Converter
Celsius, Fahrenheit, gas mark and fan oven settings.
PPM to Percent Converter
Convert between parts-per-million, percent and ppb.
Radiation Dose Converter
Convert radiation dose between Sievert, rem, Gray and rad.
Resistor Wattage Calculator
Power dissipated by a resistor and safety margin.
Shoe Size Converter
Convert shoe sizes between US, UK, EU and centimetres.
Sound Level Distance Calculator
How sound pressure level (dB) drops with distance.
Torque Converter
Convert torque between N·m, ft-lb and kg·cm.
Typing Speed (WPM) Calculator
Words per minute and accuracy from a typing test.
Voltage Drop Calculator
Voltage drop across a wire run given gauge and length.
Wavelength-Frequency Converter
Convert between wavelength and frequency for waves.
Wire Gauge Ampacity Calculator
Estimated safe current-carrying capacity by AWG size.