Shift Calculator

Use this shift calculator to calculate hours worked between clock-in and clock-out, subtract unpaid breaks, or find what time your shift should end. Use the 8-, 10- and 12-hour presets for quick clock-out calculations, including overnight shifts that cross midnight.

Common Shift End Times

These examples show the clock-out time after the stated amount of actual work. Add an unpaid break to the end time because the break does not count as worked time.

StartWork RequiredUnpaid BreakClock Out
8:00 AM8 hoursNone4:00 PM
8:00 AM8 hours30 min4:30 PM
7:30 AM8 hours30 min4:00 PM
7:00 AM10 hours30 min5:30 PM
6:00 AM12 hours30 min6:30 PM
10:00 PM8 hours30 min6:30 AM next day

How to Use the Shift Calculator

SumHours gives you two ways to calculate a work shift:

  • Shift length — enter a start time, end time and unpaid breaks to calculate how long you worked.
  • Find clock-out time — enter your start time, required work hours and unpaid break to find when your shift should end.

Both modes handle overnight shifts that continue past midnight.

Calculate Shift Length

Choose Shift length, then enter the time your shift started and ended.

Add any unpaid break time that should not count as worked time.

The basic calculation is:

Worked time = elapsed shift time − unpaid breaks

Example:

  • Start: 8:00 AM
  • End: 4:30 PM
  • Unpaid break: 30 minutes
  • Elapsed time: 8 hours 30 minutes
  • Worked time: 8 hours

Find Your Clock-Out Time

Choose Find clock-out time when you know when you started and how many hours you need to work.

The calculator adds your required work time and unpaid break to your start time.

Clock-out time = start time + required work time + unpaid break

Example:

  • Start: 8:00 AM
  • Required work: 8 hours
  • Unpaid lunch: 30 minutes
  • Clock out: 4:30 PM

The unpaid lunch makes the total span of the shift 8 hours 30 minutes, while actual worked time remains 8 hours.

8-Hour Shift Calculator

Use the 8h preset when you need to complete eight hours of actual work.

If you also take a 30-minute unpaid lunch, use the 8h + 30m lunch preset.

Example:

  • Start: 7:30 AM
  • Required work: 8 hours
  • Unpaid lunch: 30 minutes
  • Clock out: 4:00 PM

10-Hour Shift Calculator

Select the 10h preset for a 10-hour required work period.

Example without a break:

  • Start: 7:00 AM
  • Required work: 10 hours
  • Clock out: 5:00 PM

If you add a 30-minute unpaid break, your clock-out time becomes 5:30 PM.

12-Hour Shift Calculator

Select the 12h preset for a 12-hour work period.

Example:

  • Start: 6:00 AM
  • Required work: 12 hours
  • Unpaid break: 30 minutes
  • Clock out: 6:30 PM

Overnight Shift Calculator

The shift calculator also works when a shift continues past midnight.

Example:

  • Start: 10:00 PM
  • Required work: 8 hours
  • Unpaid break: 30 minutes
  • Clock out: 6:30 AM next day

When the calculated finish time falls on the following day, SumHours marks the result as a next-day clock-out.

Why Does an Unpaid Break Make My Clock-Out Time Later?

Worked hours and total time at work are not always the same.

If you need to complete eight hours of actual work and take a 30-minute unpaid lunch, you must remain at work for eight hours and 30 minutes in total.

Example:

  • Start: 8:00 AM
  • Eight hours of work ends at: 4:00 PM
  • Unpaid break: 30 minutes
  • Final clock-out time: 4:30 PM

Use Your Current Time as the Shift Start

In Find clock-out time mode, the Use current time button fills the start-time field with the local time reported by your browser.

You can then choose your required work hours and unpaid break to estimate when your shift should finish.

Shift Hours and Decimal Hours

When calculating shift length, worked time can be shown in hours and minutes and in decimal hours.

Hours and Minutes Decimal Hours
8 hours 15 minutes 8.25
8 hours 30 minutes 8.50
8 hours 45 minutes 8.75
10 hours 30 minutes 10.50
12 hours 15 minutes 12.25

For a full conversion table, use the Time to Decimal Calculator.

Shift Calculator vs Clock In Calculator

Use the Shift Calculator when you want to calculate one shift or find when a shift should end.

Use the Clock In Calculator when you have several clock-in and clock-out punches, want to total split shifts, calculate a lunch return time or check how much time remains in your workday.

Frequently Asked Questions

What time do I leave if I start at 8 AM and work 8 hours?

With no unpaid break, an eight-hour shift starting at 8:00 AM ends at 4:00 PM.

With a 30-minute unpaid lunch, it ends at 4:30 PM.

What time does an 8-hour shift end with a 30-minute lunch?

Add eight hours of required work plus the 30-minute unpaid break to your start time.

For example, an 8:00 AM start gives a clock-out time of 4:30 PM.

What time do I leave after a 10-hour shift?

Add 10 working hours plus any unpaid break to your start time.

A 7:00 AM start with no unpaid break ends at 5:00 PM.

What time does a 12-hour shift end?

Add 12 hours of required work plus any unpaid break.

For example, a 6:00 AM start with a 30-minute unpaid break ends at 6:30 PM.

Does the Shift Calculator work past midnight?

Yes. For example, starting at 10:00 PM and working eight hours with a 30-minute unpaid break gives a clock-out time of 6:30 AM the next day.

Does an unpaid lunch count toward my work hours?

No. Enter unpaid break time separately. It increases the total elapsed span of the shift without increasing your worked hours.

Can I use my current time as the shift start?

Yes. In Find clock-out time mode, select Use current time to populate the start field using your browser’s local time.

How do I calculate an overnight shift?

Enter the actual start and end times in Shift Length mode, or enter your start time and required work duration in Find Clock-Out Time mode. SumHours handles the transition past midnight automatically.

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