Add Time Calculator - Free Hours, Minutes & Seconds Calculator
Fast and accurate time calculator to add or subtract days, hours, minutes, and seconds. Easily compute total time spent on projects, aggregate flight times, calculate payroll hours, and more.
Last updated: February 26, 2026
Time Calculation Uses & Functions
Ideal for
Freelancers & HR
Input your daily hours and minutes to find the exact sum for billing.
Ideal for
Aviation Logbooks
Perfect for logging flight legs where times must be completely accurate to the minute.
Ideal for
Media Creators
Add or subtract seconds and minutes of tracks to align audio with video scenes correctly.
Ideal for
Athletes & Runners
Combine your marathon splits or swimming laps to see total elapsed time easily.
Ideal for
Project Deadlines
Subtract an expected delay from a projected project timeframe cleanly.
Ideal for
Accounting
See exactly how many decimal hours (e.g., 2.50 hrs) a time equates to.
Quick Example Calculation
Adding 2 hrs 45 mins and 1 hr 25 mins
Standard Result
4 hrs 10 mins
Decimal Hours
4.17 hours
How Time Arithmetic Works
Unlike normal decimal arithmetic (which uses a base-10 system), time calculations use a sexagesimal system (base-60). Because there are 60 seconds in an hour and 60 minutes in an hour, adding time requires carrying over values differently.
The Carry-Over Rule (Base-60)
1. Add Seconds: If >= 60, add 1 to Minutes, keep remainder2. Add Minutes: If >= 60, add 1 to Hours, keep remainder3. Add Hours: If >= 24, add 1 to Days, keep remainderThis rule ensures that your final time is cleanly formatted. For example, 90 minutes correctly parses to 1 hour and 30 minutes.
Decimal Equivalents
A common task in business is converting hours and minutes into pure decimals (like converting 8 hours and 30 minutes into 8.5 hours). To do this manually, you divide the minutes by 60.
- 15 minutes: 15 / 60 = 0.25 hours
- 30 minutes: 30 / 60 = 0.50 hours
- 45 minutes: 45 / 60 = 0.75 hours
- Total conversion: Multiply total seconds by 1/3600 to find hours
Frequently Asked Questions
Found This Time Calculator Helpful?
Share it with your coworkers, friends, or anyone needing quick time math!