Quick answer
Hours worked is the time between the start and end of a shift minus the unpaid break. Enter the start time, end time and break length in minutes and the calculator returns the hours worked in hours and minutes and as decimal hours for pay.
If the end is earlier than the start the shift is taken to cross midnight. Decimal hours are the figure to multiply by an hourly rate: 8 h 30 min is 8.5.
Related tools: Time Card Calculator: Total hours, overtime and gross pay from daily start and end times. Time Duration Calculator: Elapsed time between two clock times, including across midnight. Days Between Dates Calculator: Number of days, weeks and months between two dates.
How to use the Hours Calculator
- Type start time, for example HH:MM (24-hour).
- Type end time, for example HH:MM (24-hour).
- Optionally, enter unpaid break (min) (a whole number, between 0 and 1440).
- Press Calculate to see the result, and use Reset to start again.
| Input | What to enter | Allowed values |
|---|---|---|
| Start time | Text, such as HH:MM (24-hour) | — |
| End time | Text, such as HH:MM (24-hour) | — |
| Unpaid break (optional) | A whole number, in min | ≥ 0, ≤ 1440 |
Formula and method
Formula
hours worked = (end − start) mod 24 h − break
Exact integer day arithmetic in UTC; no daylight-saving or time-zone effects.
Crosses midnight when the end is earlier than the start.
Worked examples
These examples are verified: each one is an automated test case that the live calculator must reproduce exactly.
Example 1
Inputs: Start time = 09:00; End time = 17:30; Unpaid break = 30.
| Result | Value |
|---|---|
| Hours worked | 8 h 0 min |
| Decimal hours | 8 |
Example 2
Inputs: Start time = 22:00; End time = 06:00; Unpaid break = 45.
| Result | Value |
|---|---|
| Hours worked | 7 h 15 min |
| Decimal hours | 7.25 |
The first line is the headline result (hours worked). Below it the hours Calculator lists decimal hours, which describe the same case from other angles. Exact integer day arithmetic in UTC; no daylight-saving or time-zone effects.
Worked example
A shift from 09:00 to 17:30 is 8 h 30 min. With a 30 minute unpaid break, hours worked is 8 h 0 min, which is 8 decimal hours.
Hours worked with breaks
09:00 to 17:30 with a 30-minute unpaid break is 8 h 0 min, or 8.0 decimal hours. An overnight shift such as 22:00 to 06:00 is 8 hours before the break.
For a week, add each day's result or use a time card calculator.
A 09:00 to 17:30 shift with different breaks
Every figure in this table comes from running this calculator, so it matches what the form returns.
| Break (minutes) | Hours worked | Decimal hours |
|---|---|---|
| 0 | 8 h 30 min | 8.5 |
| 30 | 8 h 0 min | 8 |
| 45 | 7 h 45 min | 7.75 |
| 60 | 7 h 30 min | 7.5 |
What happens with invalid input
These messages are produced by the calculator itself, so you know what to fix.
- Unpaid break: entering "90" shows "The break cannot be longer than the shift." beside that field and no result.
Choosing between the Hours Calculator and similar calculators
Each row shows what a related calculator on this site asks for and what it returns, so you can pick the one that matches your question.
| Calculator | You enter | It returns |
|---|---|---|
| [Time Card Calculator](/time/time-card-calculator/) | start times, end times and unpaid break per day | Total time |
| [Time Duration Calculator](/time/time-duration-calculator/) | start time and end time | Duration |
| [Days Between Dates Calculator](/date-calendar/days-between-dates-calculator/) | start date, end date and count end date? | Days between |
| [Date Calculator](/date-calendar/date-calculator/) | start date and operation | Resulting date |
| [Time Until Calculator](/time/time-until-calculator/) | current time and target time | Time remaining |
Background: dates and times
Date and time results depend on the conventions a tool uses: whether the end date counts, whether weekends and holidays are skipped, how months of different lengths are handled and whether time zones are applied. This page states its convention, and the worked examples show it.
Dates use the Gregorian calendar and calendar days unless the page says otherwise; check deadlines against the rule in your contract or regulation.
Assumptions and limitations
- Break longer than the shift is rejected
If a required value is empty, not a number, or outside its allowed range, the form marks that field with a message and shows no result instead of a misleading number. The automated checks deliberately try invalid entries for unpaid break to confirm this.
Frequently asked questions
Does it handle shifts that cross midnight?
Yes. If the end is earlier than the start, the end is treated as the next day.
How do I total a whole week?
Add each day's hours, or use the time card calculator.
What does the Hours Calculator calculate?
Hours worked between a start and end time, minus breaks. It returns Hours worked and Decimal hours.
What formula does the Hours Calculator use?
hours worked = (end − start) mod 24 h − break. Crosses midnight when the end is earlier than the start.
What do I need to enter in the hours Calculator?
You enter Start time and End time. Optional: Unpaid break (min).
How is the result rounded or limited?
Exact integer day arithmetic in UTC; no daylight-saving or time-zone effects. Break longer than the shift is rejected.
What is an example of a hours result?
With start time 09:00, end time 17:30 and unpaid break 30, the hours worked is 8 h 0 min.
Related calculators
- Time Card Calculator — Total hours, overtime and gross pay from daily start and end times.
- Time Duration Calculator — Elapsed time between two clock times, including across midnight.
- Days Between Dates Calculator — Number of days, weeks and months between two dates.
- Date Calculator — Add or subtract days, weeks, months or years from a date.
- Time Until Calculator — Hours and minutes from the current time until a target clock time (generalizes “how long until 3:58 PM”).
- Military Time Converter — Convert between 24-hour (military) time and 12-hour AM/PM time.
- Time to Decimal Calculator — Convert hours and minutes to decimal hours.
- Work Hours Calculator — Hours worked between a start and end time minus breaks.
Sources
- ISO 8601-1: Date and time, representations for information interchange (calendar dates, ordinal dates and week dates)
- Gregorian calendar reform, papal bull Inter gravissimas (1582): the leap-year rule used for all dates
Content last reviewed 2026-11-04. Formulas and worked examples are checked by automated tests against independently computed values.