Project Time Calculator

Work Hours Calculator: Calculate Hours Worked With Breaks and Overtime

Enter your start time, end time and unpaid break to calculate the hours you work each day, week, month and year, including night shifts and overtime.

Quick answer

To calculate work hours, subtract the start time from the end time, then subtract unpaid breaks. A 9:00 to 17:00 shift with a 30-minute unpaid break is 7 hours 30 minutes, or 7.5 decimal hours. Multiply by the days you work for the weekly total. If the end time is earlier than the start, the shift crossed midnight.

Earlier than the start means the shift ends the next day.
Total unpaid break per day.
Leave empty for no overtime.
Pay-equivalent hours only.
Log hours per task (optional)

One task per line, ending with the time as h:mm or decimal hours, for example Design review, 1:30.

How to read your result

Enter your start and end time, the unpaid break and how many days you work each week. Overtime is optional: set the weekly threshold and a multiplier, or clear the threshold to ignore it.

  • Paid time per day: the shift length minus the unpaid break, shown as hours:minutes and as decimal hours. This is the figure most payroll systems use.
  • Per week, per month, per year: the daily paid time multiplied by your days. A month is the weekly total times 52 divided by 12 (4.33 weeks) and a year is 52 weeks. Paid leave and public holidays are not removed.
  • Overtime per week: weekly paid hours above your threshold. Regular per week is the rest.
  • Pay-equivalent hours: regular hours plus overtime hours times the multiplier. Multiply by an hourly rate to get gross pay with overtime.

If you enter an end time earlier than the start, the calculator treats the shift as ending the next day, so a night shift needs no special setting. Looking for common patterns such as 9 to 5 or a 12-hour night shift? See the paid hours for common shifts.

Work hours formulas

paid time = (end − start) − unpaid break

weekly hours = paid time × days per week

monthly hours = weekly hours × 52 ÷ 12    yearly hours = weekly hours × 52

overtime = max(0, weekly hours − threshold)    pay-equivalent hours = regular + overtime × multiplier

When the end is earlier than the start, add 24 hours to the end before subtracting. Decimal hours are minutes divided by 60, so 45 minutes is 0.75 hours and 20 minutes is 0.33 hours. Everything is calculated in whole minutes and only rounded when displayed.

Worked examples

Each example uses numbers you can load into the calculator above; the results match the tool exactly.

Example 1 (simple): 9:00 to 17:00 with a 30-minute break

  • Shift length = 17:00 − 9:00 = 8 hours; minus 30 minutes = 7:30 paid (7.5 hours)
  • Week (5 days) = 7.5 × 5 = 37.5 hours, so no overtime at a 40-hour threshold
  • Month = 37.5 × 52 ÷ 12 = 162.5 hours; year = 37.5 × 52 = 1,950 hours

These are the calculator's default inputs.

Load this example

Example 2 (realistic): 8:00 to 18:30, 45-minute break, overtime after 40 at 1.5x

A site supervisor works five long days. Shift length is 10 hours 30 minutes; after a 45-minute break the paid day is 9 hours 45 minutes.

  • Week = 9.75 × 5 = 48.75 hours; regular = 40, overtime = 8.75 hours
  • Pay-equivalent hours = 40 + 8.75 × 1.5 = 53.125 hours
  • Month = 48.75 × 52 ÷ 12 = 211.25 hours; year = 2,535 hours

At an hourly rate of 20, the week is 53.125 × 20 = 1,062.50 before tax.

Load this example

Example 3: a night shift from 22:00 to 06:00

The end time is earlier than the start, so the shift crosses midnight: 2 hours before midnight plus 6 after is 8 hours.

  • Minus a 30-minute break = 7:30 paid (7.5 hours)
  • Week (5 nights) = 37.5 hours

The calculator labels the shift as crossing midnight and still gives the same totals as a day shift of the same length.

Load this example

Common shifts and what they add up to

Most people searching for work hours are checking a pattern they already know. The common work shifts hub lists the paid hours for popular day, long and night shifts, including 9 AM to 5 PM, 8 AM to 4:30 PM, 7 AM to 7 PM and 10 PM to 6 AM, each with a table of weekly, monthly and yearly totals and where every hour falls on the clock.

To track what you did within a shift, open "Log hours per task" under the calculator, list tasks with their times, and download a CSV. If you are estimating a whole project rather than one shift, the project time calculator turns effort and team size into a finish date.

How to calculate hours worked by hand

  1. Write both times in 24-hour form. 5:00 PM is 17:00.
  2. Subtract start from end. 17:00 − 9:00 = 8 hours. If the end is earlier, add 24 hours first: 06:00 becomes 30:00, and 30 − 22 = 8.
  3. Subtract the unpaid break. 8 hours − 30 minutes = 7 hours 30 minutes.
  4. Convert to decimal hours if payroll needs it: 30 ÷ 60 = 0.5, so 7.5.
  5. Multiply by days worked for the week: 7.5 × 5 = 37.5. Subtract your overtime threshold to find overtime.

Assumptions, limits and common mistakes

Assumptions and limits

  • Overtime is measured per week above one threshold. Rules based on daily limits, rest periods or night premiums are not applied.
  • A month is an average of 4.33 weeks, and a year is 52 weeks. Paid leave, public holidays and part-weeks are not removed.
  • Rounding rules used by some employers (to the nearest 5 or 15 minutes) are not applied; enter the times as you want them counted.
  • The calculator works in minutes. Seconds on a time clock are ignored.

Common mistakes

  • Forgetting the unpaid break. 9 to 5 is 8 hours on the clock but 7.5 paid hours with a 30-minute lunch.
  • Reading 7:30 as 7.30. Seven hours thirty minutes is 7.5 decimal hours, not 7.3.
  • Subtracting night shifts the wrong way. 06:00 minus 22:00 is negative; add 24 hours to the end time first.
  • Multiplying paid hours by calendar days. Use the days you actually work.

Frequently asked questions

How do I calculate work hours?

Subtract the start time from the end time and then subtract unpaid breaks. For 9:00 to 17:00 with a 30-minute break, 8 hours minus 30 minutes is 7 hours 30 minutes, or 7.5 hours.

How do I calculate hours worked in a week?

Multiply the paid time per day by the days you worked. A 7.5-hour day over five days is 37.5 hours. If days differ, add each day's paid time instead.

How do I calculate hours for a shift that passes midnight?

Add 24 hours to the end time before subtracting. From 22:00 to 06:00 that is 30:00 − 22:00 = 8 hours. This calculator does it automatically when the end time is earlier than the start.

How do I convert hours and minutes to decimal hours?

Divide the minutes by 60 and add them to the hours. 7 hours 45 minutes is 7 + 45 ÷ 60 = 7.75. The add and subtract time calculator converts both ways.

How do I include overtime?

Set "Overtime after" to your weekly threshold, such as 40, and the multiplier, such as 1.5. The calculator splits the week into regular and overtime hours and shows pay-equivalent hours.

Does the calculator count unpaid breaks?

It subtracts the unpaid break you enter from every shift. Paid breaks should be left out of the break field because they count as work time.

How many hours is 9 to 5?

Eight hours on the clock, or 7.5 paid hours with a 30-minute unpaid lunch. See 9 AM to 5 PM for the weekly, monthly and yearly totals.

Last updated 19 October 2026. Last reviewed 19 October 2026. Reviewed by . Formulas and tests: methodology.