Free Time Calculator
Add or subtract hours, minutes, and seconds.
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Inputs
Result
Result
5 h 15 m 30 s
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Short answer
Convert every value to seconds, add or subtract, then convert the total back to hours, minutes, and seconds.
What is the Time Calculator?
Adds or subtracts two durations expressed as hours, minutes, and seconds.
How does the Time Calculator work?
Convert both durations to total seconds. Add or subtract. Re-express in HMS.
Formula
Variables
A / BThe two time durations
Explanation
Converting to seconds first avoids the carry/borrow bugs that plague direct HMS arithmetic.
Examples
Example 1: 3:45:30 + 1:30:00
5 h 15 m 30 s = 5.258 hours.
Applications
- Video editing
- Cooking sequences
- Project time tracking
Advantages
- Handles borrow/carry automatically
- Multiple output formats
Limitations
- Does not span days automatically — use date calculator for multi-day durations
Common mistakes
- Adding minutes without borrowing when the result crosses 60
Tips
- To multiply a duration by a count, convert to seconds first, multiply, then re-express
Related concepts
The Time Calculator sits inside the Date & Time Calculators hub, in the time tracking & conversion cluster. Hours, timesheets and unit conversion. Understanding the terms below makes the output easier to interpret and easier to compare against neighbouring measures.
Practical use cases and industry applications
Understanding Time
Adds or subtracts two durations expressed as hours, minutes, and seconds. Within date & time calculators, time belongs to the time tracking & conversion cluster, where it shares terminology and assumptions with closely related tools.
Learning how time is calculated
Converting to seconds first avoids the carry/borrow bugs that plague direct HMS arithmetic. Working through the variables one at a time — A / B — makes the result reproducible by hand and easier to sanity-check.
Using time to make a decision
Video editing Cooking sequences Project time tracking Because outputs depend on the assumptions you enter, run more than one scenario before committing to a figure.
How time compares with related measures
timesheet, decimal hour, shift, rounding rule all describe adjacent aspects of time tracking & conversion. Comparing this calculator's output against those measures — using the related tools listed on this page — prevents a single metric from being read in isolation.
Frequently asked questions
Why negative time?
When B > A in subtraction. The magnitude is shown with a minus sign.
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