How our calculators work

Where rates and rules come from

Rate-dependent calculators share a central engine in our codebase. Income tax and National Insurance use the 2026/27 bands published by HMRC — including the £12,570 personal allowance, 20%/40%/45% bands and 8%/2% employee NI. Other statutory figures (SSP, SMP, Child Benefit, State Pension, CGT allowances and more) live in a single rates file updated each April when official figures are released.

Last updated: April 2026 (2026/27 tax year). Reviewed by LifeAdminUK Editorial: June 2026.

Official sources we cite

• GOV.UK

  Official UK government information on tax, benefits and pensions.

• HMRC

  Income tax, National Insurance and Self Assessment rates.

• MoneyHelper

  Free, impartial guidance on money and pensions (formerly Money Advice Service).

• FCA

  Borrowing, credit and financial services guidance for consumers.

Each calculator page lists the specific sources relevant to that tool. Where a tool covers benefits, we also link to the official GOV.UK benefits calculator where appropriate.

What our calculators do

• Apply published UK rates and common rules to give you a quick, good-faith estimate.
• Run entirely in your browser — we do not store the figures you enter.
• Show a breakdown where possible (tax bands, NI slices, repayment schedules) so you can see how the result was reached.
• Link to related guides and official resources for further reading.

What they do not do

• Replace payslips, P60s, benefit award letters, lender quotes or tax returns.
• Cover every edge case — tax codes, company benefits, regional variations and provider-specific terms can all change your actual figure.
• Constitute financial, legal or tax advice. See our disclaimer.

Editorial standards

• ✓Figures are sourced from official UK publications — primarily GOV.UK, HMRC, DWP and the FCA — and checked against our shared rate engine before each tax year.
• ✓Calculators provide estimates using simplified rules. They are not a substitute for payslips, benefit letters, lender quotes or professional advice.
• ✓Content is reviewed when UK rates change (typically each April) and when major policy updates affect our tools.
• ✓We link to independent help such as MoneyHelper, Citizens Advice and StepChange where readers may need further support.