How We Calculate — and How We Check
Pay calculators are only worth using if their working is open. Here is every source we use, every payroll rule our calculators follow — including the three rules much of this niche gets wrong — and how each figure is tested before it reaches a page.
Last updated November 2026 · Figures across the site checked November 2026; next scheduled check: the April 2027 pay award.
Our sources
Figures come from official publications, never from other calculator sites:
| Pay scales — England | NHS Employers, Agenda for Change 2026/27 |
| Pay scales — Scotland | Scottish Government, PCS(AFC) 2026/1 |
| Pension tiers — England & Wales | NHSBSA, "Cost of being in the Scheme" |
| Pension tiers — Scotland | SPPA circular 2026/03 |
| Tax, NI & student loan thresholds | HMRC / GOV.UK 2026/27 rates |
| Maternity & leave rules | NHS Terms and Conditions Handbook, Sections 13 & 15; GOV.UK statutory rates |
The rules we follow — including the ones others miss
Pension tiers are set by your actual pay. Not your full-time equivalent. A part-timer on £19,243.80 is tiered at 6.5%, not the 8.3% their full-time salary would suggest — a difference of £277 a year that WTE-based calculators quietly take from part-time staff. (NHSBSA and SPPA both state the actual-pay rule.)
Pension does not reduce National Insurance. NI is worked out on pay before pension contributions, because NHS pension is not salary sacrifice. Calculators that deduct pension first understate NI.
London weighting is added before the pension tier is set, because HCAS is pensionable — it can move you up a tier, and your pension builds on the higher amount.
Student loan is charged on pensionable pay above your plan threshold (9% for Plans 1, 2, 4 and 5; 6% for postgraduate) — not on pay after pension.
The £100,000 personal allowance taper is applied for higher bands, and Scotland uses its own six-band income tax system and SPPA pension tiers throughout.
How figures are tested
Every number printed on this site is generated by our calculation engine — none is typed by hand. Before any page is published, the engine must pass a set of hand-checked worked examples to the penny, including edge cases: part-time tier changes, the maternity pay cap for lower-paid staff, and the personal allowance taper. When a rule cannot be verified against an official source, the feature waits rather than shipping on a guess.
What we leave out — honestly
Our calculators cover basic pay, pension, tax, NI, student loans and London weighting. They do not yet model unsocial hours enhancements, overtime or salary sacrifice, so if those are a large part of your pay, treat our figure as your basic-pay floor and check your payslip for the rest. Estimates also assume a standard 1257L tax code; your own code can change your tax line.
Keeping it current
Pay scales, pension tiers and statutory rates are re-verified against official sources at every April pay award and uprating, and each page shows when its figures were last checked. Spotted something that looks wrong? Checking our working above is the fastest way to find out — and if we're wrong, we'll fix it and say so here.