About Numro

Numro is a UK tax calculator and financial planning tool for the self-employed. Freelancers, contractors, sole traders, anyone whose income doesn't fit on a single payslip.

It does what HMRC's own calculator should do, and what most paid tools don't: calculates your tax accurately under the 2026/27 rules, and then explains every number in plain English.

The product principle is simple. HMRC tax law is precise. The tools people use to understand it should be too. A tool that gets the £100k Personal Allowance taper wrong by a hundred pounds is not a mild error, it's the difference between a confident decision and a guess. So Numro's tax engine is deterministic Python, built from raw HMRC guidance and tested against published reference calculations across edge cases.

The AI helps with the part where AI helps. When you describe a business expense "lunch with potential client", "train to Manchester for client meeting", "monthly Adobe subscription" Numro categorises it against HMRC's allowable expense rules and tells you whether it's deductible, with the relevant guidance cited. The calculations stay deterministic. The classifications use a language model. Different tools for different jobs.

What Numro is, ultimately, is a tax tool that respects your time and your intelligence. It doesn't oversimplify (the way HMRC's own calculator does) and it doesn't assume you already understand self-assessment (the way most paid tools do). It calculates, it explains, it cites its sources, and it gets out of your way.

Numro is built and operated by Ojonugwa Egwuda, an AI engineer based in Oxford. It is registered with the UK Information Commissioner's Office under reference ZC134542.