Time Calculator
Add or subtract days, hours, minutes and seconds — or add a length of time to a date and time to find when it ends.
How to add and subtract time
Time does not use base 10: 60 seconds make a minute, 60 minutes an hour and 24 hours a day. To add times, add each unit separately and carry over whenever seconds or minutes reach 60 and hours reach 24.
total seconds = days × 86,400 + hours × 3,600 + minutes × 60 + seconds
The calculator does the carrying for you and also shows the result in decimal hours, minutes, seconds and days — 8 h 15 min is 8.25 hours or 495 minutes.
Add time to a date
Switch to Add time to a date to find the end of a period that starts at a given moment — for example, when a 36-hour rental that starts on Friday at 9:00 ends. The result includes the weekday.
Converting between units
| Unit | Seconds | Minutes | Hours |
|---|---|---|---|
| 1 minute | 60 | 1 | 0.0167 |
| 1 hour | 3,600 | 60 | 1 |
| 1 day | 86,400 | 1,440 | 24 |
| 1 week | 604,800 | 10,080 | 168 |
Frequently asked questions
How do I add hours and minutes?
Add the hours and the minutes separately, then turn every 60 minutes into one hour. 3 h 50 min + 1 h 25 min = 4 h 75 min = 5 h 15 min.
How do I convert minutes to decimal hours?
Divide the minutes by 60. 15 minutes = 0.25 hours, 45 minutes = 0.75 hours.
How many seconds are in a day?
86,400: 24 hours × 60 minutes × 60 seconds.