How to Use the Time Duration Calculator
Three modes share the same result panel. Switching tabs keeps the page layout stable.
- Choose Time between two times for hours between two clock times, with an optional unpaid break and optional dates for multi-day spans.
- Choose Add or subtract time to shift a start time by days, hours, and minutes. Cross-midnight results show next day, previous day, or a day offset.
- Choose Total hours worked for a timecard-style table. Add or remove rows, then read the total, decimal hours, and average per filled row.
- Use the 12-hour or 24-hour toggle for how results are written. Native time inputs still follow your browser’s format.
How Time Duration Is Calculated
Everything is converted to integer minutes first, then formatted for display.
A clock time such as 09:00 becomes 540 minutes from midnight. Duration is end minus start. When no dates are set and the end is earlier than the start, 24 × 60 minutes are added so overnight shifts (for example 22:00 to 06:00) resolve to eight hours. An unpaid break is subtracted after that span. If the break is longer than the span, the tool shows a message instead of a negative result.
Optional start and end dates use Date.UTC day ordinals so the browser’s time zone cannot change the minute count. 12-hour and 24-hour labels are display options only; the underlying math is the same. Same start and end with no next-day flag is zero minutes; ticking next day on equal times yields 24 hours.
Worked example: 17:30 − 09:00 = 8 h 30 min; minus a 30 min break = 8 h 00 min. That is 480 minutes, or 8.00 decimal hours.
Minutes to Decimal Hours
Decimal hours = total minutes ÷ 60. Useful for spreadsheets and some time-entry systems.
| Minutes | Decimal hours |
|---|---|
| 15 | 0.25 |
| 30 | 0.50 |
| 45 | 0.75 |
| 60 | 1.00 |
| 90 | 1.50 |
| 510 | 8.50 |
Common Uses
Practical clock-time questions this tool is built for.
- Shift length and simple time-card totals (hours worked across several days), without payroll rules.
- Study sessions, cooking times, and travel legs on a clock.
- Sports intervals and practice blocks measured in hours and minutes.
- Converting a finished span into decimal hours for a spreadsheet.
For pay-period conversion see the Salary to Hourly Calculator. For spreading a total across calendar days see the Average Per Day Calculator.
Limits of This Calculator
Clock arithmetic is not the same as payroll, travel, or legal timekeeping.
Results ignore time zones and daylight saving. A night that “springs forward” or “falls back” is still treated as a plain 24-hour wall clock. Workplaces often round punches, treat breaks differently, and apply overtime rules this page does not model.
This is not payroll, legal, or employment advice, and it does not say what breaks or hours anyone is entitled to. For counting calendar days between dates use the Days Between Two Dates calculator; for weekdays and holidays use the Business Days Calculator.
General information and estimates only. Not financial, tax, or employment advice.
Frequently Asked Questions
Hours between times, midnight crossings, decimal hours, and how this differs from date-span tools.
How do I calculate the hours between two times?
Choose Time between two times, enter a start time and an end time, and optionally subtract an unpaid break in minutes. The result shows hours and minutes, total minutes, and decimal hours. Example: 09:00 to 17:30 is 8 hours 30 minutes (8.5 decimal hours).
How do I calculate time across midnight?
If the end time is earlier than the start and you have not added dates, the calculator treats the end as the next day and labels it “End time is on the next day.” You can uncheck that box to turn the overnight rule off, or open Add dates for multi-day spans to set both calendar dates explicitly.
How do I convert minutes to decimal hours?
Divide total minutes by 60. Fifteen minutes is 0.25 hours, 30 minutes is 0.50, and 45 minutes is 0.75. This page shows decimal hours to two places and includes the exact minutes÷60 fraction in the working line.
How do I add hours and minutes to a time?
Open Add or subtract time, enter the start time, choose Add, and fill days, hours, and minutes. The result is the new clock time. If the sum crosses midnight, the panel shows next day or a day offset such as +2 days. Optional start date returns the resulting calendar date.
How do I subtract a break?
In Time between two times, enter Unpaid break (minutes). The break is subtracted from the span after the end−start difference is calculated. If the break is longer than the span, the tool shows a calm message and does not return a negative duration. Timecard rows have their own break column.
Does this calculator handle time zones or daylight saving?
No. All results are naive wall-clock arithmetic using integer minutes (and Date.UTC for optional dates). The browser time zone and daylight saving never change the numbers. For calendar day counts see Days Between Two Dates; for working-day spans see the Business Days Calculator.
How is this different from the Days Between Two Dates calculator?
This page measures hours and minutes between clock times, adds or subtracts a duration from a time, or totals a timecard. The Days Between Two Dates calculator counts calendar days (and related spans) between two dates, not shift length on a time card.
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