Self Assessment Tax Estimator 2026/27

Secure checkout by Paddle · instant download · VAT handled for you · 14-day money-back guarantee

Enter your income, expenses, pension and any PAYE salary. The spreadsheet works out your Income Tax, Class 4 National Insurance, your total bill, your effective rate, what to set aside each month, and whether you'll be caught by Payments on Account.

• Built for the 2026/27 tax year (England, Wales & NI rates)
• Handles mixed income — self-employment plus a salary plus property
• Shows the Payments on Account trap before it bites
• A monthly set-aside figure, so the bill is never a shock
• Works in Excel, Google Sheets and Numbers
• Every formula visible and editable — nothing locked, nothing hidden

Made by Fableworks HQ. Designed and built by us using spreadsheet tools with AI assistance, and every calculation is human-checked and unit-tested.

Secure checkout by Paddle · instant download · VAT handled for you · 14-day money-back guarantee