Why I built this site
CalculatorPro.co.uk started as a personal side project. I wanted to get better at building things for the web, and calculators felt like a good place to start: the logic is well-defined, the results are genuinely useful, and it's easy to tell when you've got the maths right. What began as a single mortgage calculator grew into a small collection of tools I kept coming back to myself — for working out repayments, checking percentages, and tracking BMI.
I'm not a financial adviser, a doctor, or a large publisher — just one person building tools that solve real, everyday problems, and trying to explain the numbers behind them clearly along the way.
What you'll find here
- Mortgage & Loan Calculator — repayment and interest-only estimates, overpayment savings, fees, deposit/LTV, and a UK stamp duty calculator.
- Percentage Calculator — four everyday percentage tools in one place, from VAT to percentage change.
- BMI Calculator — metric and imperial BMI with a healthy weight range and visual gauge.
Every calculator runs entirely in your browser. Nothing you type into the calculators is collected, stored, or sent anywhere — see the Privacy Policy for the full detail on cookies and analytics.
A word on accuracy
I've tried hard to get the underlying formulas right — standard amortisation maths for the mortgage calculator, current UK Stamp Duty Land Tax bands, and WHO BMI thresholds — and I keep them updated when rules change. That said, every result on this site is for general information only and isn't a substitute for advice from a qualified mortgage adviser, accountant, or doctor. Please double-check anything important before relying on it.
Get in touch
Spotted a bug, found an error in a calculation, or have an idea for a new calculator? I'd genuinely like to hear from you — head over to the Contact page.