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Head-to-head · Tax Calculators

SmartAsset Paycheck Calculator vs GOV.UK Self Assessment Tax Calculator

  • Updated Oct 2026
  • Both researched from official sources
  • 1 check side by side
Higher score SmartAsset Paycheck Calculator #2 in Tax Calculators 8.8/10 Free plan Free plan Visit SmartAsset
GOV.UK Self Assessment Tax Calculator #5 in Tax Calculators 8.5/10 Free plan Free plan Visit GOV.UK

SmartAsset Paycheck Calculator leads on 0 checks, GOV.UK Self Assessment 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 scoreSmartAsset Paycheck Calculator · 8.8/10
  • Free planboth

SmartAsset Paycheck Calculator scores higher on our rubric for tax calculators: 8.8 against 8.5 out of 10; our editors rank them #2 and #5.

On tax jurisdictions, SmartAsset Paycheck Calculator gives you Multiple where GOV.UK Self Assessment Tax Calculator offers Federal.

SmartAsset Paycheck Calculator is the better fit for U.S. employees estimating net pay. GOV.UK Self Assessment Tax Calculator is the better fit for UK self-employed people with mixed income.

  • SmartAsset Paycheck Calculator fits best

    U.S. employees estimating net pay

  • GOV.UK Self Assessment Tax Calculator fits best

    UK self-employed people with mixed income

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 SmartAsset Paycheck Calculator 8.8/10 Visit ↗ GOV.UK Self Assessment Tax Calculator 8.5/10 Visit ↗
At a glance
Editor score 8.8 8.5
Ranking #2 in Tax Calculators #5 in Tax Calculators
Best for U.S. employees estimating net pay UK self-employed people with mixed income
Pricing model Free Free
Starting price Not published Not published
Free plan ✓ ✓
Free trial — —
Deployment Cloud Cloud
Platforms Web Web
Built for Solo Solo
Specs
Calculator types Paycheck take-home pay estimates for hourly and salaried income Income Tax; Class 4 National Insurance
Tax jurisdictions Multiple Federal
Income sources Hourly wages, salary, overtime self-employment profits; property rental income; State or occupational pension; paid employment
Filing statuses Single, married Not published
Tax years Not published 2025 to 2026
Platforms Web web
Our review
Pros
  • Estimates withholding across federal, state and local taxes
  • Includes overtime and pre- and post-tax deductions
  • Breaks estimates down into taxes, deductions and take-home pay
  • 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
Cons
  • Limited to paycheck estimates for hourly or salaried income
  • Filing status inputs cover single and married
  • Does not offer broader tax-planning scenarios
  • Assumes the standard Personal Allowance
  • Does not account for savings and investment income
  • Excludes the High Income Child Benefit Charge and amounts already paid
Our verdict

SmartAsset Paycheck Calculator is a free web tool for employees estimating net pay from hourly wages or a salary. Users enter location and pay frequency, along with marital status and dependents, to see an estimated paycheck after…

Read the review →

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 →
  1. SmartAsset Paycheck CalculatorTax Calculators 8.8Free plan
  2. GOV.UK Self Assessment Tax CalculatorTax Calculators 8.5Free plan

Strengths and trade-offs

  • SmartAsset Paycheck Calculator — where it wins

    • Estimates withholding across federal, state and local taxes
    • Includes overtime and pre- and post-tax deductions
    • Breaks estimates down into taxes, deductions and take-home pay

    Where it doesn't

    • Limited to paycheck estimates for hourly or salaried income
    • Filing status inputs cover single and married
    • Does not offer broader tax-planning scenarios

  • 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
  • SmartAsset Paycheck Calculator8.8/10 · Free plan

    A free web calculator for estimating hourly or salaried take-home pay.

    Visit SmartAssetFull verdict →
  • 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 →

More comparisons

All tax calculators comparisons → · Full ranking →

Guides on tax calculators

Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026

Last updated · How we research and update