About

This is a free, open-source UK tax calculator covering the five most common situations a UK earner finds themselves in: PAYE employee, Limited Company director, Umbrella contractor, IR35 inside vs outside, and Sole Trader / Self-Employed.

What it does

The calculation engine implements HMRC's PAYE Tax Table Routines specification (v24.0, February 2026) — the same document HMRC publishes for payroll software vendors. Every prescribed rounding direction (Free Pay rounded up to 1p, Taxable Pay rounded down to £1, final tax rounded down to 1p) is followed exactly, and outputs are cross-checked against HMRC's own reference vectors for tax years 2024/25, 2025/26 and 2026/27.

Who built it

Built and maintained by Loglux Ltd, a UK-registered software company. It stays free for end users; future B2B widget licensing (separate from this free tier) is planned.

Why it exists

Most UK take-home calculators online are lead-gen funnels for accountancy services. The numbers are usually right for textbook scenarios but drift on edge cases — K-codes, marriage allowance, Scottish bands with non-Scottish dividends, contractor IR35 inside vs outside. This calculator aims to be the boring, accurate one: same engine HMRC's spec describes, no upselling.

Bug reports & feedback

Found something wrong? Use the contact form and describe the scenario — input values, tax year, and what the result should be. We aim to respond within a couple of business days.

Disclaimer

This calculator is not financial or tax advice. See the full Terms of Use and Privacy Policy.