About calcd

calcd is a UK project building free money calculators that are quick to use and honest about what they show. We make the tools we wanted ourselves: put in your figures, get the number, and see exactly how it was worked out.

What we build

Every calculator covers a common UK money question, from mortgage repayments and take-home pay to stamp duty, dividends and capital gains tax. Each one is built for UK rules rather than adapted from a generic global tool, so the bands, thresholds and allowances match what actually applies here.

How the calculators are built

The rules live in code, not in a spreadsheet copied from somewhere else. Each tax calculator holds the current rates and thresholds as fixed figures, and we lock the logic with worked examples we check by hand, so a known input always returns the known answer. Every result is broken down on the page so you can follow the working rather than take it on trust.

Where the figures come from

Statutory figures come from primary sources only: gov.uk and HMRC for UK tax, the Scottish Government for Scottish income tax bands, and the Bank of England for the base rate. We use places like MoneyHelper and Citizens Advice to sanity-check how we explain things, never as the source of a number, and we do not take rates from other people's calculators or second-hand summaries.

Keeping it current

Tax rules change, usually at the Budget and at the start of each tax year. Each calculator records the tax year it is built for and the date we last checked its figures, and we run a check that flags any calculator that has fallen behind so it gets updated. When a rate changes, we update the figure, the page copy and the date together.

Estimates, not advice

Every result is an estimate to help you plan. It is not financial, tax, legal or mortgage advice, and it cannot account for your full circumstances. For anything that matters, confirm the number with the relevant authority, your lender or a qualified adviser before you act on it.

Found something wrong?

We would rather know. If a figure looks off or a calculator does not behave as you expect, tell us through the contact form and we will look into it. Accuracy is the whole point, so corrections are welcome.