House of Calculator is a free website of calculators and plain-English guides for money, tax, health, dates, travel and home. It has 98 tools and 50 guides, and it is built UK-first: British English, pounds and dates in the order you expect, with the 2026/27 tax year’s rules built in.
The idea is simple. You have a number to work out, whether that is take-home pay, a mortgage payment, a due date, a paint quantity or a percentage. You should be able to get a clear answer quickly, see how it was worked out, and move on.
Our principles
Show the working and the assumptions. A result is only useful if you know what it is based on. Each calculator states the assumptions it makes, and our guides explain the method in ordinary language so you can check the sums yourself.
No sign-up. There are no accounts, no forms and no email addresses to hand over. Open a tool and use it.
No clutter. Calculators should look like calculators. We keep pages light and focused on the task.
Works on phones. Most people reach for a calculator on their phone, so every tool is designed to work comfortably on a small screen.
UK-first. The tax, National Insurance, student loan and property tax tools follow UK rules, including the separate Scottish income tax bands, LBTT in Scotland and Land Transaction Tax in Wales. Many other tools, such as percentages, units, BMI and time zones, work anywhere.
Private by design. Calculations run in your browser. Nothing you type into a calculator is sent to our servers. Our Privacy Policy explains what little data is handled.
How we keep it accurate
Rates and thresholds are taken from official UK sources, including GOV.UK, GOV.SCOT and Revenue Scotland, and GOV.WALES. We test the tools against worked examples and check the results against the standard formulas. Where a figure depends on your own circumstances, such as your energy tariff or your lender’s fees, we ask you to enter it rather than guessing.
Our guides are date-stamped, so you can see when they were last updated. If you spot a mistake, please tell us, and include the numbers you entered if you can.
What we are not
House of Calculator gives general information. It is not financial, tax, legal, mortgage or medical advice, and it does not replace a qualified adviser, HMRC, the NHS or your lender. Results are estimates, and tax rates and rules change. Check GOV.UK or the relevant official source before making a decision that matters. Our Terms of Use set out the details.
Where to start
Popular starting points include UK take-home pay for pay after tax, Stamp duty for home purchases and Mortgage calculator for monthly repayments. If you would rather read first, try UK income tax explained: bands, allowance and how it's worked out or How mortgage repayments are calculated. There is also a list of common questions on the FAQ page.
Contact
To suggest a calculator, report a mistake or ask a question, email hello@houseofcalculator.com.
What’s next
We plan to add more calculators and guides, and to cover more countries over time. If there is a tool you would like to see, let us know.