How we source tax-band figures
Each provider's data on this site is taken from that provider's own published source. This page describes the source per provider, the refresh discipline, and what we do not publish.
Sources, by provider
- UK: HMRC published rates and thresholds. Income Tax bands, National Insurance Class 1 rates and thresholds, Personal Allowance, Scottish-rate-of-income-tax bands, and Student Loan plan thresholds taken from gov.uk/income-tax-rates and gov.uk/national-insurance-rates-letters.
- US (federal): IRS published brackets. Federal income tax brackets by filing status, FICA (Social Security + Medicare) rates and wage base, Additional Medicare Tax thresholds taken from the IRS Tax Tables and Publication 15 / 15-T.
- US (state-by-state). State income-tax rates from each state Department of Revenue or equivalent authority, with no-tax states (FL, NV, SD, TX, WA, WY, TN, NH on dividends/interest only) explicitly listed.
- Statutory deduction reference. UK Auto-Enrolment pension thresholds (DWP / TPR published), US 401(k) contribution limits (IRS annual notice), HSA / FSA limits where applicable.
What we deliberately do not publish
- Personalised tax advice. This site applies published bands. It does not advise on individual tax positions; for personal tax advice, consult a qualified accountant or tax adviser.
- Aggressive tax-mitigation guidance. We describe statutory allowances (ISA, AE pension, 401(k), HSA) factually but do not publish guidance on aggressive avoidance schemes.
- Personal salary data. Calculators run entirely in your browser. Your salary inputs are not transmitted, logged, or stored.
Update cadence
Site values update only when the underlying reality changes. Triggers:
- UK Spring or Autumn Budget changes that affect Income Tax / NI bands
- Annual IRS Tax Table refresh (typically October-November for next tax year)
- State income-tax rate change in any covered state
- Major statutory deduction change (Student Loan plans, AE pension thresholds, 401(k) limits)
Cosmetic date bumps are not made.
Editorial position
This site is operated by Digital Signet, an independent AI-development studio. Digital Signet does not provide tax advice, does not act as an accountancy practice, does not sell financial-services products, and takes no paid placement or sponsored coverage from any tax-prep, payroll or financial-services vendor. The site does not carry affiliate links or sponsored product placements. See /about for the operator and the wider network.
Editorial direction is set by the Digital Signet editorial team. Drafts are produced via Digital Signet's autonomous AI development methodology and reviewed against the editorial framework before publication.
Contact
For methodology questions, corrections, or scenarios that don't fit cleanly: oliver@digitalsignet.com.