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Shift Hours Calculator

Calculate shift hours including overnight shifts and rotation coverage.

About Shift Hours Calculator

Overnight shifts must wrap past midnight, otherwise the span comes out negative. Multiplying by shifts and staff gives the total hours a rota consumes, which is the rostering figure. Naive subtraction producing negative hours for night shifts is the single most common rostering software bug.

Formula

Shift Hours

Shift hours = clock span − unpaid break, wrapping past midnight when needed

clock span
Elapsed time from start to end, adding 24 hours if it crosses midnight

Worked example

With the default values below, Shift Hours Calculator returns Paid Hours per Shift of 7.750. Change any input above and every figure here is recalculated in your browser.

Inputs used

Shift startaccepts 0–23.75 h
22 h
Shift endaccepts 0–23.75 h
6.5 h
Unpaid breakaccepts 0–240 min
45 min
Shifts per weekaccepts 0–21
4
Staff per shiftminimum 0
3

Results

Paid Hours per Shift
7.750 h
Weekly Hours per Person
31.000 h
Clock Span of the Shift
8.500 h
Total Weekly Staff Hours
93.00 h
Crosses Midnight
Yes

Step by step

  1. 1Values used
  2. 2Shift Hours
  3. 3Paid Hours per Shift= 7.750 h
  4. 4Weekly Hours per Person= 31.000 h
  5. 5Clock Span of the Shift= 8.500 h
  6. 6Total Weekly Staff Hours= 93.00 h
  7. 7Crosses Midnight= Yes

Assumptions and limits

  • The result is derived only from the 5 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
  • Figures are rounded for display to 3 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

How is Shift Hours calculated?

Shift hours = clock span − unpaid break, wrapping past midnight when needed Overnight shifts must wrap past midnight, otherwise the span comes out negative. Multiplying by shifts and staff gives the total hours a rota consumes, which is the rostering figure.

Why does Shift Hours matter?

Naive subtraction producing negative hours for night shifts is the single most common rostering software bug.

What values do I need to enter?

This calculator takes 5 inputs: Shift start, Shift end, Unpaid break, Shifts per week, Staff per shift. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.

Related Calculators

Shift Hours Calculator – Calculate Paid Hours per Shift