Tax Calculation Sources
Last reviewed: July 2026 · Updated for the 2026/27 tax year
Primary sources
PayToolkit calculators are built directly from official UK government and HMRC publications, including:
- HMRC Income Tax rates and Personal Allowances
- HMRC National Insurance thresholds and rates
- HMRC dividend tax rates and allowances
- HMRC Capital Gains Tax rates and allowances
- HMRC VAT rates and registration thresholds
- HMRC Corporation Tax rates
- UK Government Stamp Duty Land Tax bands
- DVLA vehicle tax (VED) bands
Official links
You can verify any calculator against the official source at gov.uk/income-tax-rates, gov.uk/national-insurance, and the wider gov.uk business tax section.
How often sources are checked
Rates are checked against official sources at the start of each tax year and after any Budget or in-year policy announcement. See Methodology for the full update process.