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-rates-letters, 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.