Time Duration Calculator
Last updated: September 23, 2026
How long between start and end? Type two times, get the duration in hours, minutes, and totals.
Calculate the time between a start and end time. Outputs hours, minutes, and a clean readable duration. Check the "next day" toggle for overnight shifts. Useful for shift tracking, project time logs, and figuring out how long something actually took.
Examples: 09:15 → 12:00 = 2h 45m · 22:30 → 06:15 (next day) = 7h 45m
How a single duration is calculated
Enter a start time and an end time. With the next-day box unchecked, the duration is end minus start. If that result would be negative, the page stops and asks you to check the box instead of guessing. With the box checked, the duration is the time from the start until midnight, plus the end time after midnight: (24 hours − start) + end. That path is how a 22:30 to 06:15 shift becomes a real length instead of an error.
Three figures describe the same span. The readable duration is hours and minutes, such as 7h 45m. Total minutes is that span as a single minute count, which is convenient for billing rules that talk in minutes. Total hours is the decimal, rounded to three places, which is the figure most timesheets multiply by an hourly rate. A range line repeats the two times and notes when the next-day box was on, so a screenshot still shows the assumption.
Breaks are not subtracted. There is no weekly sum and no pay rate. One interval is the whole job of this page. Several shifts belong on the Time Card Calculator with Lunch Breaks, which also wraps an overnight automatically and can split hours at a weekly threshold.
Worked examples
Example 1: A morning block
Start 09:15, end 12:00, next day unchecked. The gap is 2 hours 45 minutes, 165 minutes, and 2.750 hours. A billing rate applied to 2.750 hours matches a rate applied to 165 minutes. Applying it to "2.45" would be wrong, because 45 minutes is 0.75 hours, not 0.45 hours.
Example 2: An overnight shift
Start 22:30, end 06:15, next day checked. From 22:30 to midnight is 1 hour 30 minutes (90 minutes). From midnight to 06:15 is 6 hours 15 minutes (375 minutes). Total 465 minutes, which is 7h 45m, or 7.750 hours. Leave the box unchecked and the page will warn you, because 06:15 is earlier than 22:30 on the same clock face.
Example 3: Decimal hours on an invoice
Fifteen minutes is 0.250 hours. Thirty minutes is 0.500. Forty-five minutes is 0.750. Ninety minutes is 1.500. The total-hours field already uses this conversion, to three decimals. If a client wants quarter-hour rounding, round the clock times to the quarter hour first, then calculate, so the rounding rule stays visible.
Example 4: A class period
Start 13:00, end 14:20. Duration 1h 20m, 80 minutes, 1.333 hours. Two of those periods are 2.666 hours. Add the decimal hours yourself when you have a handful of intervals, or move to the work-hours page if the handful is really a week of shifts with breaks.
Example 5: The next-day box left on by mistake
Start 09:00, end 17:00, with next day checked, is not an 8-hour day. The formula adds a full trip past midnight: 15 hours until midnight, plus 17 hours, which is 32 hours. Uncheck the box for any end time that is later on the same calendar day. The box means "this end is tomorrow," not "this might be a long shift."
When to use this
Use it for one shift, one meeting, one nap or feeding interval, one travel leg, or one lab timer you wrote down as a start and a stop. Parents and caregivers use the minute count to compare intervals. Freelancers use the decimal hours on an invoice. Hourly workers use it to check a single punch pair before those punches go into a weekly total.
It is the wrong tool for "how many days until a date." That is the Date Difference Calculator or the Countdown Calculator. It is also the wrong tool for age. Birthdays live on the Age Calculator.
Common mistakes
- Next day checked on a daytime shift. The result grows by 24 hours. Glance at the range line; it will say "next day" when the box is on.
- Next day left off on an overnight. You get a warning rather than a duration. Check the box and calculate again.
- Reading 7.75 as 7 hours and 75 minutes. The digits after the decimal are a fraction of an hour. 0.75 × 60 = 45 minutes.
- Subtracting lunch twice. This page does not remove a break. If you already shortened the end time to skip lunch, do not subtract lunch again in the weekly tool.
- Ignoring a daylight-saving night. The clock loses an hour in spring and repeats an hour in autumn. This tool always uses a 24-hour day. On those two nights, adjust by the hour the clock added or removed.
Limitations
One pair of times, no dates, and no second overnight. A span longer than a single pass through midnight needs the date difference tool for the days, plus this tool for the leftover clock time, added carefully so the shared midnight is not counted twice. No time zones, no seconds, and no payroll rounding. Checking next day on a shift that already ends later the same day overstates the length, as the 32-hour example shows. The page cannot tell a typo from a real overnight without the checkbox.
FAQ
Why does work hours wrap overnight by itself, while this page asks?
A weekly timesheet is full of shifts, and an end earlier than a start is usually a night shift. A single duration might be a typo. The checkbox is the confirmation. Use it only when the end really is the next calendar day.
How do I turn minutes into decimal hours?
Divide minutes by 60, or read the total-hours field. 90 minutes ÷ 60 = 1.5 hours. 20 minutes ÷ 60 = 0.333 hours, which matches the three-decimal display.
Can I add several durations?
Yes, by adding the decimal hours or the minute totals. For a week that also has unpaid breaks and an overtime line, the work-hours calculator is built for that sum.
Does the result include seconds?
No. The time fields are hours and minutes. A timer that shows seconds should be rounded to the nearest minute before you type it, using whatever rounding rule the timesheet uses.
What is the duration from a time to the same time?
Unchecked, the same time in both fields is 0 minutes. Checked, the same time next day is 24 hours. A full day on duty is the checked case, and a forgotten punch is more often the unchecked zero.
Practical tips
Write the pretty duration and the decimal on the same note: "7h 45m (7.750)." Invoices and payroll systems disagree when one person uses 7.75 and another types 7.45. Uncheck next day as a habit before a daytime entry, and look at the range line after every overnight.
If you are logging billable time, start the clock when the work starts and stop it when the work stops, then calculate once. Editing the end time to "make it a round number" and also rounding the decimal is two rounds. Pick one rounding rule.
For a commute or a flight with a layover, calculate each leg and add the decimals. A layover is its own interval if you need it included, and it is omitted if you only want wheels-up to wheels-down. The tool will not infer which one you meant.