Your pro rata pay
£21,000
£35,000 ÷ 37.5 × 22.5 · 60% of full-time
Pro Rata Pay Calculator UK
Whether you work part-time hours or you are starting or leaving a job partway through a month, the pay that reaches your account is the pro rata amount, not the full-time figure. This pro rata pay calculator works out both. Use the part-time mode to convert a full-time salary into your actual pay, or the part-month mode to see what a starter or leaver is owed for the days worked. It is free, built for the UK, and uses 2026/27 figures. If you only need the annual figure, the pro rata salary calculator covers that, and every tool sits under the main pro rata calculator hub.
What pro rata pay means
Pro rata means "in proportion", so pro rata pay is the share of a full-time wage you earn for the time you actually work. It comes up in two everyday situations. The first is part-time work, where your weekly hours are below full time. The second is a partial pay period, such as starting a job mid-month or leaving before the month ends, where you are paid only for the days you were employed.
In both cases your rate of pay stays the same. You are simply paid for less time, so the total is smaller. That is the whole idea behind pro rata pay: a fair slice of the full amount, worked out in proportion to your hours or days.
How the pay calculator works
The calculator has two modes. In part-time mode, you enter the full-time salary, the standard full-time hours, and your own hours. It returns your pro rata pay for the year, then breaks it down into monthly, weekly and hourly figures so you know what to expect on each payslip.
In part-month mode, you enter your annual salary, the number of days in the month, and the days you actually worked or were paid for. It returns the pay for that month, along with your full monthly pay and daily rate for comparison. This is the mode to use for a first or final payslip, where the month is only part worked.
The pro rata pay formula
For part-time pay, the formula divides the salary by full-time hours to find an hourly value, then multiplies by your hours:
Pro rata pay = (full-time salary ÷ full-time hours) × your hours
A £35,000 role at 37.5 hours, worked at 22.5 hours, gives £21,000 a year. For a part-month, you take your monthly pay and scale it by the days worked. Monthly pay of £2,500 in a 30-day month with 12 days worked comes to £2,500 ÷ 30 × 12 = £1,000 for that month. Both are the same proportional idea, applied to different time periods.
Working out pay by hours or days
Part-time pay is most accurate when worked out by hours, since hours are the unit your contract is usually built on. You compare your weekly hours against full-time hours and apply that ratio to the salary. If your role is described in days instead, a four-day week is 80% of full-time pay and a three-day week is 60%, which gives you a quick shortcut without touching the hours.
Part-month pay, by contrast, is worked out by days. Most UK employers use calendar days for a starter or leaver, dividing the monthly pay by the days in the month and multiplying by the days employed. Some use working days instead, so it is worth checking which method your payroll applies, as the two can give slightly different results.
Pro rata pay for a part-month
Starting or leaving a job in the middle of a month is where pay catches people out. You will not receive a full month’s pay in your first or last month unless you happen to start on the first or leave on the last day. Instead, payroll works out the days you were employed and pays you for those.
Say you start on the 12th of a 30-day month on a salary that pays £2,500 a month. You were employed for 19 days, so your first pay is roughly £2,500 ÷ 30 × 19, around £1,583. The same applies when you leave. Your final payslip covers only the days up to your leaving date, plus any holiday you have built up but not taken. The part-month mode in the calculator gives you this figure straight away.
Your daily rate explained
A daily rate is useful when you need to value a single day of work, for unpaid leave, extra days, or checking a part-month figure. There are two common ways to work it out, and they answer slightly different questions.
Dividing the annual salary by 260, the number of working days in a year, gives the value of one working day. On £30,000 that is about £115. Dividing the monthly pay by the calendar days in the month gives the rate payroll usually uses for a part-month, which is a smaller figure because it spreads pay across every day, not just working days. Knowing which one applies helps you check that a deduction or part-month payment is right.
Pro rata pay examples
The table below shows full-time pay broken down across a year at a range of UK salaries. The daily rate uses 260 working days. Use the calculator for your own hours or for a part-month.
| Annual salary | Monthly pay | Weekly pay | Daily rate |
|---|---|---|---|
| £24,000 | £2,000 | £461 | £92 |
| £30,000 | £2,500 | £577 | £115 |
| £36,000 | £3,000 | £692 | £138 |
| £42,000 | £3,500 | £808 | £162 |
| £48,000 | £4,000 | £923 | £185 |
These are gross figures before deductions. They give you a clear baseline to compare against your payslip, whatever your working pattern.
Monthly, weekly and hourly pay
Once you have your pro rata pay for the year, it helps to see it the way it actually arrives. Divide the annual figure by 12 for monthly pay, by 52 for weekly, and use the hourly value for shift or overtime planning. A £21,000 pro rata salary works out at £1,750 a month, about £404 a week, and roughly £17.95 an hour at 22.5 hours.
Seeing all three matters because most people are paid monthly but budget weekly, and an hourly figure is the fairest way to compare two jobs with different hours. The calculator shows the breakdown automatically so you do not have to convert anything yourself.
Pay when you start or leave a job
Your first and last payslips are almost always pro rata. On joining, you are paid from your start date to the end of that pay period. On leaving, you are paid up to your final day, with any accrued but untaken holiday added on top. If you took more holiday than you had built up, your employer may deduct the difference from your final pay.
The holiday side of this follows the same logic as your pay, and you can work out exactly what leave you are owed with our pro rata holiday calculator. Keeping both figures to hand makes it easy to check that a final payslip is complete.
Pro rata pay and your take-home
The calculator gives gross pay, the amount before anything is taken off. Your take-home pay is lower, because Income Tax, National Insurance, pension contributions and any student loan come out first. These deductions apply to your pro rata pay, not the full-time figure.
Working fewer hours can push your pay below a tax or National Insurance threshold, which sometimes means you keep a slightly larger share than the headline rates suggest. The exact net amount depends on your tax code and circumstances, so once you have your gross pro rata pay, run it through a take-home pay or tax calculator for the figure that actually lands in your account.
Overtime, bonuses and pro rata pay
Pro rata pay covers your contracted hours, but extra earnings are handled separately. Overtime is usually paid at your normal hourly rate or higher, on top of your pro rata pay, for hours worked beyond your contract. A bonus, on the other hand, is often pro-rated for part-time staff, so a part-timer receives a share of a bonus in proportion to their hours.
The same goes for many other parts of your package. Pension contributions track your actual pay automatically, and benefits such as sick pay are commonly worked out on a pro rata basis. Under UK employment law, part-time workers cannot be paid a lower rate than full-time colleagues for the same work, which keeps the hourly value fair across the board.
Checking your pay is correct
It is worth checking your pay rather than assuming the figure is right, especially in a first or final month. For part-time pay, divide your hours by full-time hours and multiply the full-time salary by that percentage, then compare with your payslip. For a part-month, divide your monthly pay by the days in the month and multiply by the days you worked.
If the numbers do not match, it is worth raising with payroll, since errors in start dates, hours or working pattern are easy for a system to make. You can cross-check the related figures, from annual salary to holiday, using the salary calculator and holiday calculator in the same pro rata calculator hub.
Last updated June 2026 for the 2026/27 year. Employment points are based on GOV.UK guidance on part-time workers' rights. Pay figures are estimates; check your contract and payslip for exact amounts.