TimeCalculator
Do sums with hours, minutes and seconds the easy way. This free Time Calculator adds, subtracts and multiplies time values — enter hours, minutes and seconds, pick an operation, and read the answer in HH:MM:SS and in decimal hours.
Calculate Time Values
Enter two time values, choose an operation and see the result.
How the Time Calculator Works
Any time sum in four quick steps.
Enter First Time
Fill in the hours, minutes and seconds of the first value.
Choose Operation
Pick Add, Subtract or Multiply; multiply adds a field for the factor.
Enter Second Time
Fill in the second time value for adding or subtracting — multiplying doesn't need one.
View Results
See the answer as HH:MM:SS, decimal hours, total minutes and total seconds.
What Is a Time Calculator?
How time arithmetic works, and why a dedicated tool helps.
Time arithmetic basics
A Time Calculator does maths with time values. Time is base 60 — 60 seconds to a minute, 60 minutes to an hour — so carrying and borrowing happen at 60 rather than at 10.
Add 30 minutes to 45 minutes and you get 75 minutes, which is really 1 hour 15 minutes. That base-60 conversion is done for you on every result.
The carryover method
The carryover method is ordinary column addition with one change: you carry at 60. When seconds pass 59, carry a minute; when minutes pass 59, carry an hour.
Subtraction works the other way. To take 45 minutes from 20 minutes, borrow an hour as 60 minutes: 80 − 45 = 35 minutes, and the hours drop by one.
Multiplication for scheduling
Multiplying time is handy for a repeating task: four cycles of 1h 15m make 5h 0m. Behind the scenes the duration becomes seconds, is multiplied, then converted back.
When to Use a Time Calculator
Jobs where time arithmetic by hand gets fiddly.
Payroll Processing
Total daily work hours across a week, take off break times, then multiply the decimal hours by the rate.
Fitness & Training
Add up lap times, total a workout duration, or multiply one set by the number of sets.
Video & Audio Production
Sum clip durations on a timeline, total a podcast length, and subtract intro and outro to find net content.
Project Estimation
Add up task durations for a project, or multiply a per-item time by the quantity for a batch estimate.
Cooking & Recipes
Combine prep time, cook time and rest time, or scale timings when you double a batch.
Travel Planning
Add flight durations and layover times for the whole trip, or subtract a leg to isolate one direction.
Quick Time Calculation Examples
Everyday sums people run through a time calculator.
Adding work shift durations
Morning shift: 4h 30m + Afternoon shift: 3h 45m = 8h 15m total; the 30 + 45 = 75 minutes become 1 hour 15 minutes.
Subtracting break time
Total shift: 8h 00m − Lunch break: 0h 45m = 7h 15m net work, borrowing done for you.
Multiplying task time
One assembly: 0h 22m × 12 units = 4h 24m total: 1,320 seconds × 12 = 15,840 seconds, which converts back to 4h 24m.
Decimal hour output
Each answer also comes in decimal hours for payroll: 7h 15m is 7.25 hours and 8h 15m is 8.25 hours.
Time Calculator Quick Examples
Common time arithmetic operations, worked step by step.
Add Hours, Minutes and Seconds
Subtract Hours, Minutes and Seconds
Multiply a Time Duration
Calculate Time Between Two Times
Find the exact time difference between two clock readings.
Calculate the Difference Between Start and End Time
Start: 9:00 AM → End: 5:30 PM → Result: 8 hours 30 minutes.
Write both in 24-hour time (9:00 and 17:30) and subtract: 17:30 − 9:00 = 8h 30m. The calculator converts for you.
Calculate Overnight Time
Start: 10:00 PM → End: 6:00 AM → Result: 8 hours.
An end time earlier than the start means midnight was crossed, so 24 hours are added to the end: (6:00 + 24:00) − 22:00 = 8 hours.
Calculate Time Between Two Dates and Times
Start: Monday 9:00 AM → End: Wednesday 2:30 PM
Result: 2 days, 5 hours, 30 minutes. Two full days are 48 hours; add the remaining 5h 30m for 53h 30m in total.
Calculate Work Hours
Work out work hours with breaks taken off and a decimal result.
Work Hours With Break
Start: 9:00 AM · End: 5:00 PM · Break: 1 hour
Hours Worked: 7 hours. The shift spans 8 hours; take off the 1-hour break for net working time.
Work Hours in Decimal Format
7 hours 30 minutes = 7.50 decimal hours.
Payroll and invoicing need decimal hours: divide the minutes by 60 and add them to the hours — 30 ÷ 60 = 0.50, so 7 + 0.50 = 7.50.
Overnight Work Shift
Start: 10:00 PM → End: 6:00 AM · Break: 30 minutes
Worked: 7 hours 30 minutes. The overnight span is 8 hours, less the 30-minute break.
Convert Time to Decimal Hours
Move between ordinary time format and decimal hours for payroll and invoices.
How to Convert Minutes to Decimal Hours
Use Minutes ÷ 60 = decimal part of an hour. 45 minutes ÷ 60 = 0.75, so 7 hours 45 minutes is 7.75 decimal hours.
Common Time to Decimal Hour Conversions
| Time (HH:MM) | Decimal Hours |
|---|---|
| 15 minutes | 0.25 |
| 30 minutes | 0.50 |
| 45 minutes | 0.75 |
| 1h 15m | 1.25 |
| 1h 30m | 1.50 |
| 2h 30m | 2.50 |
| 7h 30m | 7.50 |
| 8h 45m | 8.75 |
Calculate Time From a Starting Time
Move any clock time forward or back by a time duration.
Add Hours and Minutes to a Clock Time
9:30 AM + 2h 45m = 12:15 PM. Minutes first: 30 + 45 = 75, which is 1 hour 15 minutes. Then hours: 9 + 2 + 1 carried = 12, so the answer is 12:15 PM.
Subtract Hours and Minutes From a Clock Time
6:00 PM − 2h 30m = 3:30 PM. Take off 2 hours to reach 4:00 PM, then 30 minutes more for 3:30 PM.
Calculate Across Midnight
11:00 PM + 3h 30m = 2:30 AM (next day). In 24-hour time, 23:00 + 3:30 = 26:30; anything past 24:00 rolls into the next day, so subtract 24 to get 2:30 AM.
Time Calculation Formula and Visual Guide
The rules of time arithmetic, set out clearly.
Adding Time
Add the seconds first; if they reach 60, take away 60 and carry a minute. Do the same from minutes to hours and from hours to days — this cascading carry underpins every time addition.
Subtracting Time
Borrowing example: 1h 10m − 25m. Because 10 − 25 is negative, turn one hour into 60 minutes: 0h 70m − 25m = 45 minutes.
Converting Time Units
- 1 hour = 60 minutes
- 1 minute = 60 seconds
- 1 hour = 3,600 seconds
- 1 day = 24 hours
Real-World Time Calculator Examples
Practical time calculations from everyday life.
Work Shift Example
8:30 AM → 5:30 PM − 1h break
= 8 hours
A 9-hour shift less a 1-hour lunch break.
Meeting Duration Example
2:15 PM → 3:45 PM
= 1h 30m
End minus start: 3:45 − 2:15 = 1 hour 30 minutes.
Travel Time Example
2h 45m + 1h 20m + 45m
= 4h 50m
Three flight legs added into one travel total.
Project Task Example
45m + 1h 20m + 2h 15m
= 4h 20m
Three tasks added to estimate the total effort.
Study Time Example
50m × 5 sessions
= 4h 10m
One 50-minute study session multiplied by five.
Overnight Shift Example
11:00 PM → 7:00 AM
= 8h
The shift crosses midnight: (7 + 24) − 23 = 8 hours.
Time Calculator Output Explained
What each time calculator result format means.
Hours, Minutes and Seconds
HH:MM:SS reads like a clock and is the default answer for every operation — the quickest to understand at a glance.
Decimal Hours
Decimal hours express the minutes and seconds as a fraction of an hour, the base-10 form that payroll, invoicing and project software expect.
Total Minutes
The whole duration as one number of minutes — useful for comparisons and for spreadsheet formulas that need a single unit.
Total Seconds
The duration in seconds, the smallest unit shown; audio and video editing and scientific work often prefer it.
Time Calculator FAQ
Answers to common questions about the Time Calculator.
Enter the first time in hours, minutes and seconds, choose "Add", enter the second time and press Calculate. For example, 2h 30m + 1h 45m gives 4h 15m, with the extra minutes carried into hours for you.
Yes. Choose "Subtract", enter the larger time first and the amount to take away second. Borrowing is handled automatically — if the minutes would go negative, an hour is converted into 60 minutes.
Enter a duration such as 1h 30m, choose "Multiply" and type a factor, say 3. The answer, 4h 30m, is the total for a task repeated that many times.
Hours, minutes and seconds (HH:MM:SS), with up to 999 hours per value. Each result is shown both as HH:MM:SS and as decimal hours.
Yes — total a week of daily hours, take off breaks, or multiply a per-unit time by a quantity. The decimal hours figure is ready to paste into a payroll sheet.
Yes. It is free and needs no account, and all arithmetic happens in your browser.
Put both times in the same form — minutes after midnight or 24-hour time — subtract, then convert back. 9:00 AM to 5:30 PM is 17.5 − 9 = 8.5 hours, or 8 hours 30 minutes.
Add 24 hours to the end time before you subtract. For 10:00 PM to 6:00 AM, use 22:00 and 30:00 (6 + 24): 30 − 22 = 8 hours.
Find the span from clock-in to clock-out, then subtract the break. 9:00 AM to 5:00 PM is 8 hours; with a 1-hour lunch that leaves 7 hours worked.
Divide by 60: 45 minutes ÷ 60 = 0.75 hours, so 7 hours 45 minutes is 7.75 decimal hours.
Add minutes and hours separately and carry an hour whenever the minutes reach 60. 9:30 AM + 2h 45m: 30 + 45 = 75 minutes = 1h 15m, and 9 + 2 + 1 = 12, giving 12:15 PM.
Subtract hours and minutes separately, borrowing an hour as 60 minutes if needed. 6:00 PM − 2h 30m: treat 6:00 as 5:60, then 5:60 − 2:30 = 3:30 PM.
Let the hours run past 24, then subtract 24 and move to the next day. 11:00 PM + 3h 30m = 23:00 + 3:30 = 26:30, which is 2:30 AM the following day.
Totals beyond 24 hours are kept as hours rather than turned into days — for example 36h 15m — so you always see the exact duration.