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- Time Calculator: Add or Subtract Time
Time Calculator: Add or Subtract Time
Find out what time it will be after a number of hours and minutes — or what time it was that long ago. Starts from the current time by default, and tells you when the answer crosses into another day.
- Which day
- Same day
- 24-hour time
- 2137
- Time moved
- 8 h 30 min
Saved setups
Save a set of inputs you reuse — your usual rate, your loan, your room sizes — and load it back in one tap.
Your recent calculations
Results you calculate here are kept on this device so you can come back to them.
Formula
How to use it
- Leave the starting time as now, or set your own.
- Choose later or earlier.
- Enter hours and minutes — 90 minutes works as well as 1 hour 30.
Worked examples
8 hours and 30 minutes after 10:15 pm
- The time will be
- 6:45 AM
- Which day
- Next day
- 24-hour time
- 0645
3 hours before 1:20 am
- The time will be
- 10:20 PM
- Which day
- Previous day
Useful for
Timing a roast or a load of laundry, working out when a parking ticket or a medication dose runs out, counting back from a flight to when you need to leave, and finding when an 8-hour shift or a 20-minute nap ends.
Questions people ask
What time will it be in 8 hours?
Add 8 to the current hour and subtract 12 or 24 if you pass noon or midnight. From 10:15 pm it will be 6:15 am the next day.
What time was it 3 hours ago?
Choose “earlier” and enter 3 hours. From 1:20 am the answer is 10:20 pm on the previous day.