Methodology & Data Sources
This page sets out exactly where the figures come from and how the calculation is performed, so you can check our working rather than take it on trust.
Last reviewed: 18 August 2026
Where the pay data comes from
| Source | What we use it for |
|---|---|
| School Teachers’ Pay and Conditions Document (STPCD) | The statutory document setting all teacher pay ranges in England. |
| School Teachers’ Review Body reports | Annual pay recommendations to the Secretary of State. |
| Teachers’ Pension Scheme | Tiered member contribution rates and career-average scheme structure. |
| NASUWT and NEU published pay scales | Cross-check against the STPCD tables; DfE remains definitive. |
| HMRC rates and thresholds | Income tax, National Insurance and student loan thresholds for 2026/27. |
Pay figures are transcribed from the published circulars and cross-checked against a second source where one exists. Where sources disagree, the official document takes precedence.
How the calculation runs
The engine applies deductions in the order a real payroll does, because the order changes the result:
- Gross pay is assembled from basic pay plus any allowances, enhancements and overtime.
- Pension contributions are deducted first, at the tier that applies to your pensionable pay. Pension is relieved at source, so it reduces taxable income.
- Income tax is applied to the remainder, using your tax code’s personal allowance. Above £100,000 the allowance tapers by £1 for every £2 of adjusted net income, and the calculator applies that taper.
- National Insurance is calculated on gross pay (not post-pension pay) at 8% between the primary threshold and the upper earnings limit, then 2% above it.
- Student loan repayments are applied against the correct plan threshold.
- Post-tax deductions such as union subscriptions come last, out of net pay.
Scottish taxpayers are routed through the Scottish income tax bands, which differ from the rest of the UK at middle and upper incomes. National Insurance and student loan thresholds remain UK-wide.
Testing and verification
The engine is checked against a set of fixed reference scenarios each time the pay data changes. Each scenario is chosen to sit on a boundary where errors show up — the basic-rate ceiling, the National Insurance upper earnings limit, the £100,000 personal-allowance taper, and the top of each pension tier. A change that moves any reference figure by more than a few pounds is treated as a regression and investigated before release.
Figures are rounded for display but calculated at full precision. Small differences against your payslip are normal and usually come from mid-year pay changes, tax-code adjustments, or your employer’s specific payroll timing.
Known limitations
- Figures assume a full tax year on the same pay point. Mid-year promotions, acting-up periods and pay-award back pay are not automatically modelled.
- Emergency and non-cumulative tax codes are not modelled; the calculator assumes a cumulative code.
- Local variations agreed at employer level may not be reflected where they are not published nationally.
- The calculator does not model benefits in kind beyond the salary sacrifice options provided, nor does it give pension transfer or retirement advice.
The 2026 STRB award is expected in autumn 2026. Until the DfE publishes the new STPCD, the site shows the 2025/26 scales.
Spotted something we have got wrong? Email contact@teacherstakehome.co.uk.