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Head-to-head · Tax Calculators

GOV.UK Self Assessment Tax Calculator vs HMRC PAYE Tax Calculator

  • Updated Oct 2026
  • Both researched from official sources
  • 1 check side by side
Higher score GOV.UK Self Assessment Tax Calculator #5 in Tax Calculators 8.5/10 Free plan Free plan Visit GOV.UK
HMRC PAYE Tax Calculator #7 in Tax Calculators 8.3/10 Free plan Free plan Visit HMRC

GOV.UK Self Assessment Tax Calculator leads on 0 checks, HMRC PAYE Tax Calculator on 0, and 1 is even. Who comes out ahead on the 1 yes/no, price and count check where we have data for both products. The editor score weighs everything else too.

Our verdict

  • Highest scoreGOV.UK Self Assessment Tax Calculator · 8.5/10
  • Free planboth

GOV.UK Self Assessment Tax Calculator scores higher on our rubric for tax calculators: 8.5 against 8.3 out of 10; our editors rank them #5 and #7.

GOV.UK Self Assessment Tax Calculator is the better fit for UK self-employed people with mixed income. HMRC PAYE Tax Calculator is the better fit for UK employers checking employee PAYE by pay period.

  • GOV.UK Self Assessment Tax Calculator fits best

    UK self-employed people with mixed income

  • HMRC PAYE Tax Calculator fits best

    UK employers checking employee PAYE by pay period

Advertiser disclosure: iTechGuides is reader-supported. Vendors can pay for top positions in our rankings and for a place on other products' pages, and we may earn a commission when you click some links. How we rank.

Side by side

Feature GOV.UK Self Assessment Tax Calculator 8.5/10 Visit ↗ HMRC PAYE Tax Calculator 8.3/10 Visit ↗
At a glance
Editor score 8.5 8.3
Ranking #5 in Tax Calculators #7 in Tax Calculators
Best for UK self-employed people with mixed income UK employers checking employee PAYE by pay period
Pricing model Free Free
Starting price Free plan Free plan
Free plan ✓ ✓
Free trial — —
Deployment Cloud Cloud
Platforms Web Web
Support Docs Docs
Built for Solo Small business, Mid-market, Enterprise
Specs
Calculator types Income Tax; Class 4 National Insurance PAYE employee Income Tax per pay period
Tax jurisdictions Federal Federal
Income sources self-employment profits; property rental income; State or occupational pension; paid employment Employee pay
Filing statuses Not checked yet Not checked yet
Tax years 2025 to 2026 2026 to 2027 (current tax year)
Platforms web web
Our review
Pros
  • Estimates Income Tax for the 2025 to 2026 tax year
  • Includes Class 4 National Insurance for self-employed users
  • Combines self-employment, rental, pension, and employment income
  • Calculates employee Income Tax for the current tax year
  • Supports weekly, fortnightly, four-weekly and monthly pay periods
  • Can account for previous-period gross pay and tax due
Cons
  • Assumes the standard Personal Allowance
  • Does not account for savings and investment income
  • Excludes the High Income Child Benefit Charge and amounts already paid
  • Focused on employee PAYE Income Tax, not annual tax estimates
  • Requires the employee’s tax code, payment date and gross pay
  • Previous-period gross pay and tax due may also be needed
Our verdict

GOV.UK’s Self Assessment Tax Calculator is a free web tool from HM Revenue & Customs for estimating Income Tax for the 2025 to 2026 tax year. For self-employed users, it also estimates Class 4 National Insurance. It is aimed at people who…

Read the review →

HMRC PAYE Tax Calculator is a free web tool for employers checking an employee’s Income Tax for a pay period in the current tax year. It is aimed at UK payroll checks, using the employee’s tax code, payment date, pay frequency and pay…

Read the review →
  1. GOV.UK Self Assessment Tax CalculatorTax Calculators 8.5Free plan
  2. HMRC PAYE Tax CalculatorTax Calculators 8.3Free plan

Strengths and trade-offs

  • GOV.UK Self Assessment Tax Calculator — where it wins

    • Estimates Income Tax for the 2025 to 2026 tax year
    • Includes Class 4 National Insurance for self-employed users
    • Combines self-employment, rental, pension, and employment income

    Where it doesn't

    • Assumes the standard Personal Allowance
    • Does not account for savings and investment income
    • Excludes the High Income Child Benefit Charge and amounts already paid

  • HMRC PAYE Tax Calculator — where it wins

    • Calculates employee Income Tax for the current tax year
    • Supports weekly, fortnightly, four-weekly and monthly pay periods
    • Can account for previous-period gross pay and tax due

    Where it doesn't

    • Focused on employee PAYE Income Tax, not annual tax estimates
    • Requires the employee’s tax code, payment date and gross pay
    • Previous-period gross pay and tax due may also be needed
  • GOV.UK Self Assessment Tax Calculator8.5/10 · Free plan

    A free web calculator for estimating 2025–26 tax across several income sources.

    Visit GOV.UKFull verdict →
  • HMRC PAYE Tax Calculator8.3/10 · Free plan

    A free web calculator for employers checking UK employee PAYE by pay period.

    Visit HMRCFull verdict →

More comparisons

All tax calculators comparisons → · Full ranking →

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Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026

Last updated · How we research and update