NHS Back Pay Calculator: Work Out Your Arrears 2026/27

Last updated: 13 October 2026 · Figures verified against the NHS Employers 2026/27 pay circular.

By the NHS Bands Pay editorial team

The calculator

How the calculation works

The calculator uses the same formula payroll applies to the basic-pay element of your arrears. Every Agenda for Change award takes effect on 1 April, but the money often does not reach payroll for weeks or months. The catch-up for those months is:

(New annual salary − old annual salary) ÷ 12 × months owed

Three numbers, each needing a short explanation. The new annual salary is your 2026/27 rate: the full-time equivalent figure for your band and pay step, taken from the NHS Employers pay circular. The old annual salary is what you were paid before the award: usually the 2025/26 rate for the same band and step. The difference between them is the annual uplift, and one twelfth of it is the monthly uplift — the extra pay you should have received in each month since April. Multiply by the number of months owed and you have the gross arrears.

The calculator defaults to the 2026/27 position: a 3.3% award, effective 1 April 2026. For a Band 5 nurse at the entry step, the figures work out like this:

The same method works for any award in any year. Change the award percentage and the calculator derives your old salary as new ÷ (1 + award), which is how payroll estimates it when the archive figure is not to hand. Change the months and the arrears scale linearly: every extra month of delay is worth one more monthly uplift. Read the full background in our NHS back pay and arrears guide.

Finding your old (pre-award) salary

The calculator offers three routes to your old salary, in order of reliability. Pick your band and pay step and it fills in the 2025/26 archive figure for you. These are the published pre-award scales: Band 2 £24,465; Band 3 £24,937 to £26,598; Band 4 £27,485 to £30,162; Band 5 £31,049 to £37,796; Band 6 £38,682 to £46,580; Band 7 £47,810 to £54,710; Band 8a £55,690 to £62,682; Band 8b £64,455 to £74,896; Band 8c £76,965 to £88,682; Band 8d £91,342 to £103,433; Band 9 £107,537 to £125,637. (Intermediate steps are not published in the archive, so the calculator derives those from the award percentage instead.)

If you have an old payslip, type the figure from it: your actual pre-award basic pay beats any archive. This matters if you were promoted or moved pay steps mid-year, because your old salary was only the pre-award rate for part of the arrears period. If neither is available, leave the old-salary box at 0 and the calculator derives it from the award percentage as new ÷ 1.033 for the 2026/27 award.

One caution: the archive route assumes you stayed on the same step all year. If you moved from the entry to the intermediate step of Band 5 in October, payroll reconstructs the arrears month by month at each rate. The calculator cannot do that reconstruction, so treat its figure as the check, not the answer. Our 2026/27 pay rise guide sets out the award that created these figures.

When back pay applies: the 2026/27 position

Back pay only arises when an award is implemented late. In England the 2026/27 Agenda for Change award of 3.3%, effective 1 April 2026, was implemented on time: April payrolls carried the new rates, and no catch-up exercise was needed. For most English staff the calculator is a what-if tool and a way to sense-check past awards.

Where implementation lags, arrears accrue month by month. In Northern Ireland, the 3.3% uplift was recommended but not yet implemented as of late August 2026, meaning affected staff were owed roughly five months of arrears and counting: for a Band 5 nurse at the entry step, about £85.33 a month, or around £427 at five months. When implementation lands there, the arrears arrive as a single lump sum, taxed in the month of payment. Scotland agreed a multi-year deal on its own timetable, and Wales implemented the 3.3% uplift with a living-wage floor, so the arrears story differs by nation. Our Northern Ireland pay guide tracks that position.

The timing also affects who gets the arrears. If you left the NHS during the arrears period, your former employer still owes you the arrears for your months in post, usually paid in a later mop-up run. If you joined mid-period, you are owed nothing for the months before you started. If you moved between trusts, each trust pays for the months you worked there. Keep your contact details current with former employers, because leavers' arrears are paid to the bank details the trust holds.

Part-time staff: pro-rating the arrears

Part-time staff receive the same percentage uplift applied to their part-time salary. The formula is identical, just starting from a smaller base. A Band 5 nurse at the entry step working 0.6 whole-time equivalent (22.5 hours a week) is owed 60% of the full-time arrears: six months works out at £512.00 × 0.6 = £307.20 gross.

Enter your whole-time equivalent fraction in the calculator: your contracted hours divided by 37.5. Common values are 0.5 (18.75 hours), 0.6 (22.5 hours), 0.8 (30 hours) and 0.9 (33.75 hours). The calculator scales the gross arrears by this fraction, and it also scales the backdated pension deduction, because the pension comes off the part-time arrears at your tier rate.

One detail part-timers often miss: your pension tier is assessed on your whole-time equivalent pay, not your actual part-time pay. A 0.5 WTE Band 6 nurse on £19,979.50 actual pay is still tiered on £39,959, the full-time figure. The calculator auto-sets the tier from the full-time salary you select, which is the correct treatment. See our part-time pay guide for the wider picture.

Backdated pension contributions

The gross arrears figure is not what lands in your bank account. Your pension contributions for the arrears months are recalculated at the higher pay, and the extra pension is deducted from the lump sum. The calculator applies your contribution tier percentage to the gross arrears automatically.

The 2026/27 tiers in England and Wales are: 5.2% on pay up to £13,259; 6.5% to £28,854; 8.3% to £35,155; 9.8% to £52,778; 10.7% to £67,668; and 12.5% above. (These 2026/27 tier thresholds are provisional estimates, not yet formally published; the 2025/26 official table is close but not identical.) For the Band 5 entry example, six months of arrears at £512.00 lose £42.50 to backdated pension at 8.3%, leaving £469.50 before tax and National Insurance.

This is one of the three usual reasons the arrears figure feels smaller than expected: the backdated pension, the tax taken in the payment month, and month-by-month reconstruction differences. There is a silver lining. Because the NHS scheme uses the net pay arrangement, the pensionable portion of the arrears reduces that month's taxable pay, and the extra pensionable pay counts toward your career-average pension — a late award does not short-change your retirement. Staff with the old 1995 or 2008 sections are unaffected in practice for these calculations, since virtually all current accrual is now in the 2015 scheme.

Tax and National Insurance on the lump sum

Arrears are taxed in the month they are paid, added to that month's taxable pay. For most staff the lump sum stays within the 20% band and the annual tax bill is unchanged. If a large lump sum pushes one month's pay into the 40% band, a normal cumulative tax code rebalances the over-deduction through later months automatically, so the annual bill still comes out right.

National Insurance is trickier. NI is calculated per pay period, not cumulatively, so arrears paid in one month can attract slightly more NI than if the same money had been spread across the months it relates to. The difference is small, a few pounds on a typical arrears payment, but it is real and it is not refunded. The calculator deliberately stops at the pre-tax figure: your tax position depends on your code, your other income and the month the arrears land, and no web tool can see those.

One more tax point worth knowing: because pension contributions are backdated off the arrears, the amount on which you pay tax that month is the arrears after the pension deduction, not the gross figure. On the Band 5 six-month example, tax is charged on £469.50, not £512.00. And if your arrears are large enough to push you toward the annual allowance territory for pension tax, that is a separate annual test with its own carry-forward rules, covered in our pensions section.

Worked examples by band

The table below shows what a 3.3% award delayed by three months is worth across the bands, for full-time staff on the entry step (Band 5 uses entry and top; all figures from the published 2026/27 and 2025/26 scales). All are gross, before the backdated pension and tax:

To verify one row: Band 5 entry, old £31,049, uplift £1,024 a year, £85.33 a month, £256.00 for three months, pension £256.00 × 8.3% = £21.25. To scale to a different delay, multiply the monthly uplift by your months: six months doubles the arrears figure, nine months triples it.

These are basic-pay arrears only. If you worked unsocial hours during the arrears period, the enhancements uplift too: the percentages apply to the higher basic rate, so a Band 5 nurse on the entry step earns an extra £0.88 an hour of night work on top of the basic uplift. Overtime and bank shifts worked in those months are normally recalculated as well, though some trusts handle bank pay through separate arrangements. Add those lines from your payslip to the calculator's result for the full picture.

Checking the arrears on your payslip

When the arrears month arrives, the payment appears as a clearly labelled arrears line on that month's payslip, separate from your basic pay, which should by then show the new uplifted rate going forward. Run through this check before assuming an error:

1. Basic pay line: confirms the new rate is live for future months.
2. Arrears line: should roughly match monthly uplift × months owed, after the backdated pension. Use the calculator to get the expected figure first.
3. Pension deduction: should be higher than usual for one month, reflecting the backdated element.
4. Tax code: should be unchanged. If it has shifted, that is a separate problem to raise.

If the figure looks materially wrong, raise it with payroll quoting the pay month and the arrears line, and check your ESR record first: a mid-period promotion, pay-step move or hours change is the most common innocent explanation. Keep the payslip. The arrears line is your proof of the catch-up if anything is queried later, and it matters for tax-year records too.

Finally, remember the calculator is an estimate and payroll is the record. If your situation involves any of the complications above — a promotion during the arrears period, a move between trusts, a period of maternity or sick leave — the reconstruction behind your payslip is month-by-month and no single formula reproduces it. Use the calculator as the sense-check it is designed to be, and let payroll be the final word.

Frequently asked questions

How is NHS back pay calculated?

Back pay is (new annual salary minus old annual salary) divided by 12, multiplied by the number of months the award was delayed. For a Band 5 nurse moving from £31,049 to £32,073, the annual uplift is £1,024, so six months of arrears are £512.00 gross. Backdated pension contributions are deducted from that figure, and tax is taken in the month the lump sum is paid.

Do I get back pay if the 2026/27 award was paid on time?

No arrears arise when the award is paid on time. The 2026/27 3.3% award reached England payrolls in April 2026, so no back pay was needed. Arrears do arise wherever implementation is delayed — in Northern Ireland the 3.3% uplift had not been implemented as of late August 2026, so staff there were accruing arrears month by month until it landed.

How does the calculator know my old salary?

Pick your band and pay step and the calculator fills in your 2025/26 salary from the published archive figures. If you prefer, enter your old salary manually from an old payslip, or let the calculator derive it as new salary divided by (1 + award percentage).

I work part time. How does that change the calculation?

The same percentage uplift applies to your part-time salary, so enter your whole-time equivalent fraction (for example 0.6 for 22.5 hours a week) and the calculator scales the arrears accordingly. Your pension tier is still assessed on your whole-time equivalent pay, not your part-time pay.

Does back pay include unsocial-hours enhancements and overtime?

Yes. Unsocial-hours enhancements and High Cost Area Supplement earned during the arrears period are uplifted, because the percentages apply to the higher basic rate. Overtime and bank shifts worked in those months are normally recalculated too. This calculator covers basic pay arrears and the backdated pension; check your payslip for the enhancement lines separately.

Is this estimate guaranteed?

No — it is an estimate. Payroll reconstructs the arrears month by month, so promotions, pay-step moves, hours changes or trust changes during the arrears period all change the real figure. Use this calculator to sense-check the number, then confirm with your payroll department or ESR record.

Sources and independence

Source: NHS Employers — 2026/27 Agenda for Change pay circular.

Source: NHS Employers — Pay award and pay review process.

Source: NHS Business Services Authority — NHS Pensions member contributions.

This is an independent guide and is not affiliated with the NHS. The 2026/27 position described (3.3% paid on time in England; recommended but not yet implemented in Northern Ireland as of late August 2026) reflects the position at the time of writing and may have moved on — check your trust's communications for the latest. Worked examples are estimates; your actual arrears depend on your band, step, hours, enhancements and tax position.