Sources and Last Updated
Every rate on this site, where it came from, and when it was last checked. All figures were verified on 29 August 2026.
United Kingdom
| What | Source |
|---|---|
| Income tax rates, bands and allowances | HMRC, Rates and thresholds for employers 2024/25, 2025/26, 2026/27 |
| Scottish rates and bands | gov.scot, Scottish income tax rates and bands, cross-checked against HMRC's operative employer guidance |
| National Insurance thresholds and categories | HMRC, Rates and thresholds for employers; National Insurance category letters |
| Student loan thresholds | HMRC employer guidance and GOV.UK, Repaying your student loan |
| Auto-enrolment thresholds | The Pensions Regulator; DWP written statement HCWS1206, 18 December 2025 |
| Statutory payments and sick pay reform | HMRC employer guidance; Employment Rights Act 2025 |
| National Living Wage | GOV.UK, National Minimum Wage rates from 1 April 2026 |
| NHS Agenda for Change scales and HCAS | NHS Employers, Pay scales 2026/27, published 12 February 2026 |
| NHS Section 2 unsocial hours | NHS Terms and Conditions of Service Handbook, Section 2 |
| NHS Pension Scheme tiers | NHS Employers and NHS Business Services Authority |
| Teacher pay scales | NEU and NASUWT published scales, derived from the accepted 3.5% award |
| Teachers' Pension contributions | Teachers' Pensions, changes to member contributions from 1 April 2026 |
| Threshold freeze extension | Autumn Budget, 26 November 2025 |
United States
| What | Source |
|---|---|
| Federal withholding tables | IRS Publication 15-T (2026), revised 3 December 2025, and the 2024 and 2025 editions |
| Statutory brackets and standard deduction | Revenue Procedure 2025-32 and prior years |
| Social Security wage base | Social Security Administration, contribution and benefit base |
| Contribution limits | IRS Notice 2025-67 and Revenue Procedure 2025-19 |
| OBBBA deductions | IRS, One Big Beautiful Bill provisions for individuals and workers |
| State withholding | Each state's Department of Revenue withholding guide, listed on that state's page |
Figures we could not confirm
Listed in full on the methodology page. In summary: the statutory STPCD 2026, the Scottish, Welsh and Northern Irish Agenda for Change scales, the SPPA and HSC pension tiers, and the 2026 withholding rules for seventeen US states. Each affected page carries a note explaining what is uncertain and why.
How often this is updated
Rates live in a small number of data files that the whole site is generated from. Changing a figure in one place and rebuilding updates every page, table and calculator at once. That is the reason nothing on this site can be out of date in one place and current in another.