Irish Calculators
Work & pay

Work Hours Calculator with Breaks

Add shift records to calculate total worked hours after unpaid breaks. Each record must span less than 24 hours, and overlapping shifts are not detected automatically.

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Your numbers

One shift per line: start HH:mm or HH:mm:ss, finish in the same format, unpaid break minutes (decimals allowed). A finish before start means the following day. Equal times mean zero hours.
hours
Use +1 for an extra hour worked across a clock change or −1 for an hour skipped; otherwise 0.
Your figures stay on this device.

How the calculation works

Work-hour totals are built from individual clock-in and clock-out records after unpaid breaks. Overnight records are supported, while a separate known clock-change adjustment accounts for an elapsed hour that a simple wall-clock subtraction cannot identify.

For each shift, subtract clock-in from clock-out, add 24 hours if overnight, then subtract unpaid breaks. Sum the hours and any known daylight-saving adjustment.

  1. Find each clock-time duration

    Subtract start from finish. A finish earlier than start is treated as the following day; equal times mean zero duration, not a 24-hour shift.

  2. Deduct unpaid breaks

    Subtract the stated break from that shift. A break longer than the shift is invalid. Paid breaks that remain part of credited work should not be deducted here.

  3. Add shifts and the known adjustment

    Sum the worked durations and apply the separate adjustment once. The result includes decimal hours and an hours-and-minutes duration, with seconds where needed.

Worked example: Day and night

Sample inputs demonstrate the method. They are not a forecast or product offer.

The first example has a 09:00–17:30 shift with thirty unpaid minutes, giving eight working hours. A 22:00–06:00 overnight shift with no break adds eight more. With no clock adjustment, the total is sixteen hours.

Shift records
09:00, 17:30, 30 22:00, 06:00, 0
Known clock-change adjustment (hours)
0

Expected result

Total worked hours
16
Worked example: Half-hour break

Sample inputs demonstrate the method. They are not a forecast or product offer.

Shift records
08:00, 12:00, 30
Known clock-change adjustment (hours)
0

Expected result

Total worked hours
3.5

Understanding your result

Decimal hours are useful for multiplying by a pay rate. The duration display is a different representation of the same time, rounded to the nearest second rather than treating decimal fractions as minutes.

Every record must span less than 24 hours. Separate days and split shifts need separate lines, and the calculator does not detect overlapping records or determine overtime entitlement.

Questions you might have

What does this work hours calculator include?

Add worked hours across shifts, deduct unpaid breaks and handle overnight shifts with a clear second-level convention.

Which assumptions should I check?

Each shift is shorter than 24 hours. Equal start and finish means zero, not a full day. Separate days or split shifts should be entered on separate lines; overlapping records are not automatically detected.

Is 8.25 hours the same as 8 hours 25 minutes?

No. Decimal hours use fractions of an hour: 8.25 hours is 8 hours 15 minutes. Both formats are shown in the result.

Choosing the right inputs

Shift records
Enter one line per shift: start time, finish time and unpaid break minutes. Times accept HH:mm or HH:mm:ss, and break minutes may contain decimals.
Known clock-change adjustment
Use a known adjustment to the total, such as an extra or skipped hour across a clock change. Leave zero when no adjustment is required; the tool does not infer one from dates.

Common mistakes to avoid

  • A finish before start always means an overnight record; check that it was not simply entered backwards.
  • Do not subtract the same unpaid break in the record and again through a negative clock-change adjustment.

Assumptions to check

  • Each shift is shorter than 24 hours. Equal start and finish means zero, not a full day. Separate days or split shifts should be entered on separate lines; overlapping records are not automatically detected.

Sources and method

Read our calculation and testing approach.