Start a job on the 15th and your first payslip won't be a full month's salary. How much it is depends on the method your employer uses, and the three common ones can differ by £40 or more on a £36,000 salary. This page works out all three so you can see the range before payday.
Leaving mid-month? Set the first day to the 1st and the last day to your final day.
Enter a salary and the first day you work to see the part-month pay.
Methods vary between employers, so your contract or payroll policy decides. Ask payroll which one they use if the figure matters to you. These are the usual three.
The working days method takes one month's salary and multiplies it by the working days you cover, divided by the working days in the month. Weekends drop out, so the result changes from month to month. It's the closest to "paid for the days I actually worked".
The calendar days method does the same with every day of the month, weekends included. A 31-day month with 17 calendar days left is 17/31 of the monthly salary, whatever days of the week they fall on.
The 365-day method skips the month altogether. It divides the annual salary by 365 and multiplies by the days covered. It rarely matches the other two, because months aren't equal lengths.
One month of this salary is £3,000.00. October 2026 has 22 working days (Monday to Friday) and 31 calendar days. From the 15th to the 31st you cover 12 working days and 17 calendar days.
Working days: £3,000.00 × 12 ÷ 22 = £1,636.36
Calendar days: £3,000.00 × 17 ÷ 31 = £1,645.16
365 days: £36,000 ÷ 365 × 17 = £1,676.71
The spread between the lowest and highest is £40.35 for the same job and the same days.
| Salary | Full month | Working days method | Calendar days method | 365-day method |
|---|---|---|---|---|
| £24,000 | £2,000.00 | £1,090.91 | £1,096.77 | £1,117.81 |
| £30,000 | £2,500.00 | £1,363.64 | £1,370.97 | £1,397.26 |
| £36,000 | £3,000.00 | £1,636.36 | £1,645.16 | £1,676.71 |
| £48,000 | £4,000.00 | £2,181.82 | £2,193.55 | £2,235.62 |
| £60,000 | £5,000.00 | £2,727.27 | £2,741.94 | £2,794.52 |
First day worked 15 October 2026, paid to the end of the month. Gross pay before tax. Monday to Friday counted as working days; bank holidays not removed.
December 2026 has 23 working days and 31 calendar days. Working from the 1st to the 23rd covers 17 working days and 23 calendar days.
Working days: £2,291.67 × 17 ÷ 23 = £1,693.84
Calendar days: £2,291.67 × 23 ÷ 31 = £1,700.27
Leavers may also be owed pay for holiday they haven't taken. That's separate from this calculation, so check your final payslip.
The gross figure above is before Income Tax and National Insurance. Tax is worked out from your tax code, and if you start without a P45 you may be put on an emergency code for a while. That can mean you pay too much at first and get it back later. Our page on the 1257L tax code explains how emergency codes work, with a worked example of a new starter.
For the full-year picture, the salary calculator shows take-home on any annual salary, and the pro-rata calculator covers reduced hours rather than a partial month.
The questions people ask when their first or last payslip is for part of a month.
Take one month's salary (annual divided by 12) and multiply it by the share of the month you worked. That share can be working days over working days, calendar days over calendar days, or you can use annual salary over 365 times the days covered. On £36,000 starting 15 October 2026 the three give £1,636.36, £1,645.16 and £1,676.71.
It depends on the employer, so check your contract or offer letter, or ask payroll. We can't tell you which one yours uses. The working days and calendar days methods are the ones we see most.
Under the calendar days method they do, because every day of the month is counted. Under the working days method they don't. This calculator counts Monday to Friday as working days.
This calculator counts them as working days to keep the sum simple. GOV.UK says bank holidays don't have to be given as paid leave, so how they're treated depends on your contract. If your payroll removes them from the count, your result will move slightly.
Yes, Income Tax and National Insurance apply as normal. If you start a job without a P45 you may be on an emergency tax code, which can mean overpaying until HMRC updates your code. GOV.UK says it's usually temporary and overpaid tax can be refunded.
The same methods apply, counting from the 1st to your last day. You may also be owed pay for untaken holiday, which sits on top of your final salary payment.
The three methods are arithmetic on your annual salary, not an official formula. Tax treatment comes from GOV.UK and HMRC.
Gross pay before tax and National Insurance. Your employer's own method decides your actual payslip. Compiled by Salary Checker UK, last updated 28 October 2026. This is general information, not financial advice.