Part-Month Salary Calculator: Pay for a Starter or Leaver Mid-Month

Work out what to pay someone who starts or leaves part-way through a month. Compare the four methods UK payrolls use, then use the one in your contract or payroll policy.

Written and reviewed by James Whitfield · Updated October 2026 · Methodology

Quick answer

Divide the monthly salary by the number of days in the month and multiply by the days employed. For a £30,000 salary (£2,500.00 a month) starting on Monday 16 November 2026, that is £2,500.00 × 15 ÷ 30 = £1,250.00. Using working days instead (11 of 21) gives £1,309.52. There is no single legal method: use the one in the employment contract or payroll policy, consistently for starters and leavers.

Enter details

Annual salary (£)

Pay month

First day paid (day of month) For a starter, their start date. For a leaver, use 1.

Last day paid (day of month) For a leaver, their leaving date. For a starter, the last day of the month.

Working days per week Bank holidays are treated as working days, as most salaried contracts do.

Calendar-days method

£1,250.00

15 of 30 calendar days of a £2,500.00 month

Calendar days in the month	£1,250.00
Working days in the month	£1,309.52
Annual salary ÷ 365 × calendar days	£1,232.88
Annual salary ÷ 260 × working days	£1,269.23

15 calendar days and 11 working days paid, out of 30 and 21 in the month. Gross pay before tax, NI and pension.

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Taking on your first employee? The payroll for one employee guide covers registering with HMRC and your first payday.

Worked example: £30,000 salary, starting Monday 16 November 2026

A new starter on £30,000 (£2,500.00 a month) starts on Monday 16 November 2026. November 2026 has 30 calendar days and 21 weekdays; from the 16th to the end of the month they are employed for 15 calendar days, 11 of them working days.

Method	Calculation	Pay for the part month
Calendar days in the month	£2,500.00 × 15 ÷ 30	£1,250.00
Working days in the month	£2,500.00 × 11 ÷ 21	£1,309.52
Annual ÷ 365	£30,000 ÷ 365 × 15	£1,232.88
Annual ÷ 260	£30,000 ÷ 260 × 11	£1,269.23

The methods differ by £76.64 on this one month. None is required by law; what matters is that you use the method in the contract or your written payroll policy, apply it consistently to starters and leavers, and that the result is at least the minimum wage for the hours worked.

Which method should an employer use?

Calendar days is the most common because it is simple and pays the same daily rate for every day in the month, including weekends. Its quirk is that the daily rate changes from month to month (a day in February is worth more than a day in March).
Working days in the month follows the days the person was actually due to work, so starting on a Monday pays more than starting on a Saturday. The daily rate also changes month to month.
Annual ÷ 365 gives one fixed daily rate all year. It is easy to explain and is often used for unpaid leave deductions.
Annual ÷ 260 (52 weeks × 5 days) gives a fixed working-day rate. Use 261 in years with 261 weekdays if your policy says so, and pro-rate the 260 for part-time patterns (208 for four days, 156 for three).

Leavers: what else goes in the final pay

Accrued but untaken holiday must be paid on leaving. Statutory leave is 5.6 weeks a year, 28 days for a five-day week, accruing pro rata through the leave year. See the holiday entitlement calculator.
Notice pay if you do not want them to work their notice. See the notice period calculator.
Give a P45 and show the leaving date on the final Full Payment Submission. Payments made after the P45 is issued are taxed on code 0T on a non-cumulative basis.

Frequently asked questions

How do you calculate salary for a partial month in the UK?

The most common method is monthly salary × calendar days employed ÷ calendar days in the month. On £30,000 starting Monday 16 November 2026 that is £1,250.00. Other payrolls use working days in the month (£1,309.52), annual salary ÷ 365 × calendar days (£1,232.88) or annual salary ÷ 260 × working days (£1,269.23).

How do I calculate pay if someone starts mid-month?

Count the days from their start date to the end of the month (inclusive), then apply your payroll method: usually monthly salary × days employed ÷ days in the month. Tax and NI are then worked out on that part-month pay using their tax code, cumulatively if they gave you a P45.

Is there a legal method for pro-rating a month's pay?

No. UK law does not set one method. The contract or your written payroll policy should say which you use, and you should apply it consistently. The result must still be at least the National Minimum Wage for the hours worked in the pay period (£12.71 an hour for those aged 21 and over in 2026/27).

Should I use 260 or 261 working days?

Either, if your policy says so. 260 is 52 weeks × 5 days; some years contain 261 weekdays and some employers use that. For part-time staff use the same idea for their pattern: 208 days for four days a week, 156 for three.

How do I work out a leaver's final pay?

Pay salary from the 1st up to and including their leaving date using your part-month method, add any accrued but untaken holiday and any notice pay, then deduct tax and NI as normal. Give them a P45 and report the leaving date on the final Full Payment Submission.

Do weekends count when calculating part-month salary?

With the calendar-days method, yes: every day in the month counts, so someone starting on a Saturday is paid for the weekend. With a working-days method only their contracted working days count.

Related tools

Pro-rata salary calculator for part-time hours and days.
Employer cost calculator for employer NI and pension on the salary.
£12.71 an hour as an annual salary, for minimum-wage checks.