Time Calculator
Add or subtract hours, minutes, and seconds, or measure the span between two clock times.
Smart Tips
• Choose add, subtract, or hours between two times before you calculate.
• Blank duration fields count as zero. 90 minutes is carried into 1 hour 30 minutes.
• Subtracting a longer duration shows a minus sign.
• An earlier end clock crosses midnight once. It does not count extra days.
• Use 9:00 AM or 21:00. Both readings are accepted.
Hours Calculator
The hours calculator is the “Hours between two times” choice above. It is not a separate page. Enter two clock times and the result is the elapsed hours, minutes, and seconds.
9:00 AM to 5:30 PM is 8 hours 30 minutes, or 8.5 decimal hours. 10:00 PM to 6:00 AM is 8 hours because the end clock is on the next day. Matching clocks are 0. Time zone conversion stays on the time zone page.
The Formula
Hours between two clock times uses the same second count. The hours calculator is that mode on this page.
Key Insights
Carry the clock
Seventy-five minutes is 1 hour 15 minutes, not a raw minute pile.
Signed subtract
A minus result means the second duration is longer than the first.
One midnight
An overnight shift from 22:00 to 06:00 is 8 hours, not a negative span.
Not a zone
This page does not move a clock between cities. That is the time zone converter.
Frequently Asked Questions
Note:Durations carry at 60 seconds and 60 minutes. If the end clock is earlier than the start, the hours calculator adds 24 hours once. This is clock arithmetic, not a time zone.