Prorated pay for joiners and leavers
Anyone employed for only part of a payroll period is paid a proportion of it. Proration is a small number of employees every cycle and a disproportionate share of payroll errors, because it is the one case where the standard calculation does not apply.
Where: Payroll › the payroll run › Payslips You need: payroll rights for that batch cycle
What proration actually does
For a monthly-paid employee, base pay is the monthly wage divided across the period's cycles and then multiplied by a proration percentage reflecting how much of the period they were employed.
For daily- and hourly-paid employees the question barely arises: they are paid for days or hours actually rendered, so a part-period is naturally a smaller number.
The consequence is that proration errors are almost entirely a monthly-paid problem, and almost entirely a dates problem.
Everything depends on two dates
| Date | Drives |
|---|---|
| Hire date | Where a joiner's entitlement starts |
| Termination date | Where a leaver's entitlement stops |
A wrong date does not produce an obviously wrong payslip — it produces a plausible one that is wrong by a few days' pay. That is far harder to spot than an obvious error and far more likely to reach the employee.
⚠️ Check the hire and termination dates before calculating, not after. Once a prorated payslip is paid, the correction is a conversation rather than an edit.
What else prorates
Proration is not only base pay:
- Other payments prorate or not, depending on the type's configuration — see Other payment types and groups.
- 13th month accrues proportionally to service, and may be subject to a minimum-service rule depending on country — see 13th month pay.
- Contributions and tax work from a monthly figure, so a part-month affects them too — a joiner's annual tax estimate is built from partial-year income unless previous-employer income is recorded.
A common mistake is assuming that because base pay prorated correctly, everything else did.
How to check a prorated payslip
- Confirm the date on the employee's record first.
- Check the base pay against the proportion of the period they were employed.
- Check allowances — some should prorate, some should not, and the type decides.
- Check contributions, which do not necessarily halve when pay halves.
- For a joiner, confirm previous-employer income is recorded if they worked elsewhere this year.
- For a leaver, work through Final pay on termination.
💡 Turn on the ready-made Hire Date and Termination Date validation rules. They flag exactly these payslips for review, automatically, every run — see Payroll validation rules.
What Happens Next
- Proration is applied at calculation from the dates on the employee's record. Correcting a date requires a recalculation to take effect.
- A mid-period joiner's tax is estimated from an incomplete year unless previous-employer income is present.
- Leavers' final payslips carry entitlements beyond prorated pay.
Tips
- Read every prorated payslip individually. There are rarely more than a handful, and they are where the errors are.
- Verify the dates against the contract, not against what is already in KAMI. The system faithfully prorates whatever date it was given.
- Watch employees who join and leave in the same period. Both ends prorate, and it is the case least likely to have been tested.
- Do not fix proration with a manual adjustment. Fix the date and recalculate, or the same error recurs next period and in the year-end figures.
Troubleshooting / FAQ
Q: A joiner's pay looks slightly wrong. Check the hire date. A few days out produces a plausible but incorrect figure.
Q: An allowance was paid in full to someone who joined mid-month. That type is not configured to prorate. Whether it should is a policy question.
Q: A joiner's tax seems too low. Their annual estimate is built from a partial year. Record previous-employer income.
Q: Contributions did not halve for a half-month employee. Contributions work from a monthly figure with their own floors and caps — they do not scale linearly with days.
Q: How do I catch these without checking everyone? Enable the hire-date and termination-date validation rules, which flag them for you.