How to Calculate the Time Between Two Times
Write each clock time as a duration from midnight, then subtract the earlier from the later. 5:30 PM minus 9:15 AM becomes "17h 45m - 9h 15m", which equals 8h 30m. If the span crosses midnight, add 24h to the end time before subtracting.
You want to know how long something lasted: a parking session, an oven timer, a study block, or a long flight. The trick is to stop thinking in clock labels and start thinking in durations. Convert each clock time into hours and minutes counted from midnight, then subtract the start from the end. This calculator does duration math only. It has no concept of "now", today's date, or the calendar, so it answers "how long between these two times" but not "what time is it after this delay".
Step by step
Turn each clock time into a duration from midnight
Read each time off the clock and rewrite it as hours and minutes since 12:00 midnight. 9:15 AM becomes 9h 15m. 5:45 PM becomes 17h 45m, because afternoon hours keep counting up: 1 PM is 13, 2 PM is 14, and so on. Midnight itself is 0h. This is the step that lets a plain subtraction work.
Subtract the earlier time from the later time
Put the later duration first and subtract the earlier one: "17h 45m - 9h 15m". The calculator handles the minute borrowing for you, so you never have to convert to a decimal or borrow 60 minutes by hand. The result is the elapsed time, for example 8h 30m.
If the span crosses midnight, add 24h to the end
When the end time is on the next day, such as parking from 10:30 PM to 6:15 AM, add 24h to the end before subtracting: "6h 15m + 24h - 22h 30m". The 24h represents one full day, so the math lands on the real overnight length instead of a negative number.
Pick the result format you want to read
Choose Hour Minute for a clean "8 hours 30 minutes" readout, or switch to the single Hour format to get decimal hours like 8.5 for spreadsheets and billing. The Minute format gives the whole span as total minutes, handy for timers and cooking.
Worked examples
14h 20m - 9h 45m=4 Hours 35 MinutesParking session from 9:45 AM to 2:20 PM.
19h 50m - 19h 05m=45 MinutesOven timer set at 7:05 PM and pulled at 7:50 PM.
16h 30m - 13h 15m=3.25 HoursAn afternoon study block from 1:15 PM to 4:30 PM, in decimal hours.
6h 15m + 24h - 22h 30m=7 Hours 45 MinutesAn overnight stretch from 10:30 PM to 6:15 AM the next morning.
Try it yourself
Type hours, minutes, days, weeks, months, years, or seconds, as full words or shorthand (h m d w), with + - * /. Pick how the answer reads with Show result as up top. It all runs in your browser. Drag the card’s right edge to make it wider.
Common questions
How do I calculate the time between two times?
Write each clock time as a duration from midnight, then subtract the earlier from the later. For 9:15 AM to 5:45 PM, enter "17h 45m - 9h 15m" to get 8h 30m. The calculator does the minute borrowing, so you do not convert anything by hand.
What if the second time is on the next day?
Add 24h to the end time before subtracting. A span from 10:30 PM to 6:15 AM becomes "6h 15m + 24h - 22h 30m", which equals 7h 45m. The 24h stands in for the full day that passed overnight.
Can it tell me what time it will be in 3 hours?
No. This is a duration calculator. It measures how long a span lasts when you give it both ends, but it has no idea what time it is now and cannot add a delay to the current clock or to a calendar date.
How do I get the answer in decimal hours?
Use the single Hour format. A 3 hour 15 minute span shows as 3.25 Hours, and 45 minutes shows as 0.75 Hours. This is the format to use for timesheets, billing, or any spreadsheet that expects a decimal.
Measure how long a parking session, oven timer, study block, flight, or overnight span lasted by subtracting two clock times.