NHS Back Pay Calculator
NHS pay awards take effect from 1 April but are often agreed months later. Everything you worked in between is owed to you as arrears. This works out how much.
Why NHS Back Pay Happens
Awards take effect from 1 April, but the review body reports later and each nation confirms on its own timetable. Until the new scale reaches payroll you keep being paid the old rate, so when it lands you are owed the difference for every month already worked.
Northern Ireland is the clearest recent example: the 2025/26 award was announced in November 2025 and paid in February 2026, ten months after it was due.
A Worked Example
A Band 5 in England on the first pay step, whose 2026/27 award reached payroll 6 months late:
| Paid all year on the 2025/26 scale | £31,049 |
|---|---|
| Owed on the 2026/27 scale | £32,073 |
| Uplift for the year | £1,024.00 |
| 6 months of it, owed as arrears | £512.00 |
That is the figure before deductions. Income tax, National Insurance and pension contributions all come off it, and because they land in a single month what reaches your account is a good deal less than £512.00. The calculator above shows both figures for your own band, nation and hours.
Why the Lump Sum Looks so Heavily Taxed
PAYE treats each month as though it were typical. A payslip carrying several months of arrears looks like a month where you suddenly earned far more, so more is taxed at a higher rate and National Insurance is higher too.
Income tax evens out; National Insurance often does not. Income tax is cumulative across the year, so an over-deduction usually corrects itself in later months. National Insurance is assessed separately in each pay period and is not reconciled annually, so a large one-off payment can genuinely cost more NI than the same money spread evenly. That is how the system works, not a payroll error.
Student Loan Repayments Follow the Same Rule
Like National Insurance, student loan repayments are worked out on what you are paid in each individual pay period rather than across the year as a whole. A payslip carrying several months of arrears therefore pulls in a larger repayment than the same money would have done spread across the months it was actually earned.
That extra repayment is not refunded automatically. It comes off the balance you owe rather than disappearing, but if your total pay for the year ends up below the annual threshold for your plan you can ask the Student Loans Company for it back.
What Arrears Do to Your Pension
Arrears of basic pay are pensionable. Contributions come out of them, and the pay counts towards the pension you build up for the year the arrears relate to.
The NHS Pension Scheme 2015 is a career average scheme, adding 1/54th of each year's pensionable pay to your pension. The £512.00 in the example above is worth roughly £9.48 a year of extra pension, payable for life from your normal pension age and revalued every year between now and then.
Being paid late does not cost you pension. Arrears are credited to the scheme year they were earned in, not the year they happen to be paid, so a delayed award builds exactly the same pension as one paid on time. The pension calculator shows what your own service is building.
What to Check When Arrears Land
- Did an increment fall during the period? Part of your arrears should then be at the higher step.
- Were enhancements uplifted? Unsocial hours are a percentage of basic pay, so backdated basic pay means backdated enhancements.
- Did your hours change? Arrears should reflect the hours actually worked in each month.
- Have you left? If you worked during the period you are generally still owed it, but former employers do not always pay automatically.