Official UK Tax Calculator: HMRC's Free Tool

The authoritative UK tax calculator is provided free by HM Revenue & Customs (HMRC).

How to Access

1. Go to: https://www.gov.uk/estimate-income-tax (direct link to "Check your Income Tax for the current year").
2. Or: https://www.gov.uk/hmrc → Search "tax calculator" → Click "Income Tax Calculator".

What It Calculates

• Income Tax (PAYE / Self Assessment)
• National Insurance (Class 1, 2, 4)
• Student Loan repayments (Plan 1, 2, 4, Postgrad)
• Net take-home pay (weekly/monthly/annual)

Inputs Required

• Tax year (current or previous)
• Gross salary / self-employment profit
• Pension contributions (employee & employer)
• Student loan plan
• Blind Person's Allowance, Marriage Allowance, age-related allowances
• Tax code (if known)

Other Reputable Calculators

• MoneySavingExpert (MSE) Tax Calculator — excellent UI, explains bands.
• Which? Tax Calculator
• The Salary Calculator (thesalarycalculator.co.uk)
• Listentotaxman.com — long-running, detailed.

Caveat: Calculators estimate. Your actual liability depends on HMRC processing, tax code adjustments, benefits-in-kind, multiple incomes, Gift Aid, etc. For complex affairs (rental, foreign income, capital gains), use an accountant or HMRC's Self Assessment portal.