What is Afterax?
Afterax is a free UK and US tax calculator and plain English tax guide website. It helps people understand take home pay, income tax, investments, deductions, retirement, and common tax thresholds using published government rules.
Afterax is an educational resource and does not provide regulated tax, accounting, legal, or financial advice.
Who builds this
Afterax is built and maintained by Qomza, LLC as an independent educational tax calculator project.
The site was created to make tax easier to understand by bringing calculators, plain English guides, and source backed rules into one place. There is no sign-up, no paywall, and no advertising.
Editorial and calculation review
Calculator rules are implemented from primary government sources, covered by automated tests, and reviewed when a new tax year or material rule change is published. Guide pages show their review date and link to their primary sources. Qomza, LLC is accountable for maintaining the software and editorial process.
If you find a calculation or explanation that may be wrong, use the contact form below. Include the calculator, tax year, inputs, and the source you believe applies. Confirmed corrections are recorded in the changelog.
You can follow Afterax on LinkedIn: Afterax on LinkedIn
What we cover
- Income tax: PAYE take home pay, National Insurance, allowances, regions, and high earner tax traps
- Bonus tax: why bonus pay can feel overtaxed and how salary sacrifice can change the result
- Salary sacrifice: pension contributions, employer match, minimum wage checks, and take home trade-offs
- Self-assessment: sole trader profit, Class 4 National Insurance, payments on account, and tax to set aside
- Salary vs dividends: limited-company owner pay, corporation tax, personal tax, NIC, and dividend tax
- Dividend tax: the £500 allowance, dividend rates, and how dividends stack on top of salary
- Capital gains tax: shares, crypto, property, and the post-October 2024 rates
- Stamp duty: SDLT, LBTT (Scotland), and LTT (Wales) with first-time buyer, additional, and non-resident rates
- VAT: net/gross conversion, Flat Rate Scheme liability, and the £90,000 registration threshold tracker
- Inheritance tax: Nil-Rate Band, Residence NRB, transferable allowances, taper, and the 36% charity rate
- Small business tax: corporation tax, marginal relief, associated companies, sole trader, and VAT calculators
- US federal tax calculators: income, payroll, capital gains, deductions, retirement, and planning estimates
How we calculate
Afterax implements UK rules from HMRC and other official UK authorities, plus US federal rules from the IRS and other official US sources. The engine runs entirely in your browser during ordinary calculator use. Values are sent only when you explicitly request an emailed summary. There's no signup, no tracking on your inputs, and no ads.
We update the engine every tax year (and out-of-band when statutory changes mid-year, like the October 2024 capital-gains reforms). Each calculator page shows when its data was last reviewed.
Where the data comes from
- HMRC income tax rates and personal allowances
- HMRC National Insurance rates
- HMRC Capital Gains Tax rates
- HMRC Stamp Duty Land Tax rates
- Revenue Scotland LBTT
- Welsh Revenue Authority: LTT
- HMRC Inheritance Tax
- IRS 2025 federal tax inflation adjustments
- Social Security Administration 2025 contribution and benefit base
- US calculation methodology and source notes
What we're not
Afterax is an educational resource. It does not provide regulated tax, accounting, legal, or financial advice. The numbers you see are estimates based on the inputs you provide and published rules from the relevant tax authority. They should help you understand your position, but they're not a substitute for advice from an accountant, a financial planner, a solicitor, or the relevant tax authority before making real decisions.
Get in touch
Spot something wrong, want a feature, or want to flag a tax-rule update we missed? Send a message, we read everything and reply by email.