What this calculator does
A shift is the finish time less the start time, less the unpaid break. From 9:00 to 17:30 with a 30 minute break is exactly 8 hours, which at $35 an hour is $280 for the day and $1,400 over a five-day week.
The overtime threshold is what turns a simple subtraction into something worth calculating. Hours past the threshold are paid at a multiplier, so the last hour of a long day is worth more than the first. At 1.5 times, a 9.5 hour day pays $358.75 rather than the $332.50 a flat rate would give.
The formula
Start and finish times are converted to minutes and subtracted, with an overnight finish handled by adding a day. The unpaid break is taken off, and the remaining hours are split at the overtime threshold: hours up to it are paid at the ordinary rate, hours beyond it at the rate multiplied by the overtime factor. The annual figure assumes 48 working weeks, which allows roughly four weeks off.
| Term | Meaning |
|---|---|
| Ordinary hours | Hours up to the daily overtime threshold, paid at the base rate. |
| Overtime hours | Hours beyond the threshold, paid at the base rate multiplied by the overtime factor. |
| Unpaid break | Time within the shift that is not worked and not paid, deducted before any pay calculation. |
| Overtime multiplier | The factor applied to the base rate for overtime, commonly 1.5 for time and a half and 2.0 for double time. |
The inputs explained
| Field | What to enter |
|---|---|
| Start time | Shift start time. |
| Finish time | Shift finish time. A finish earlier than the start is treated as an overnight shift. |
| Unpaid break (minutes) | Unpaid break in minutes. Paid breaks should not be entered here, since they count as worked time. |
| Days worked | How many days were worked at this pattern. |
| Hourly rate ($) | The ordinary hourly rate. |
| Hours before overtime starts (per day) | Hours worked per day before overtime begins. Set it above the shift length if overtime does not apply. |
| Overtime multiplier | The overtime multiplier, such as 1.5 for time and a half. |
When to use it
Checking a payslip
Working the shift out independently is the quickest way to find out whether a break was deducted twice or an overtime hour was paid flat, both of which are common and easy to miss.
Quoting for shift work
A long shift costs more per hour than a short one once overtime applies, so pricing from the ordinary rate alone will come in short on anything over the threshold.
Comparing two rosters
Four long days and five short ones can total the same hours but very different pay, because only one of them crosses the daily overtime threshold.
Worked examples
Every figure in the tables below is produced by this page’s own calculator at build time, so the numbers and the tool always agree. Select any row to load that scenario.
How does pay change as the shift gets longer?
The same start time and break with the finish time pushed progressively later.
| Finish time | Hours per day | Overtime hours per day | Daily pay | Total pay |
|---|---|---|---|---|
| 13:00 | 3.50 | 0.00 | $122.50 | $612.50 |
| 17:00 | 7.50 | 0.00 | $262.50 | $1,312.50 |
| 17:30 | 8.00 | 0.00 | $280.00 | $1,400.00 |
| 19:00 | 9.50 | 1.50 | $358.75 | $1,793.75 |
| 21:00 | 11.50 | 3.50 | $463.75 | $2,318.75 |
Questions
How do I handle an overnight shift?
Enter the times as they are. A finish time earlier than the start is read as running past midnight, so 22:00 to 06:00 gives eight hours rather than a negative figure. Shift loadings for night work are not applied automatically and would need adding to the rate.
Should a paid break be entered as a break?
No. Only unpaid time comes out of the shift. A paid rest break counts as time worked, so entering it here would cut both the hours and the pay incorrectly.
What if overtime is calculated weekly rather than daily?
This calculator applies a daily threshold. Where overtime is assessed on weekly hours instead, work out the total hours first, then split them yourself and check the result against the weekly threshold rather than the daily one.
Why does the annual figure use 48 weeks?
It allows roughly four weeks away from the pattern for leave and public holidays. It is a rough annualisation rather than a payroll figure, and it takes no account of tax, superannuation or any loading, so treat it as an indication of scale.
For adding and subtracting durations in hours and minutes, see the time duration calculator. For counting the working days in a period, see the working days calculator.