Finance calculators
UK-focused mortgage, loan, tax, investment, and salary calculators. Each one returns the number — and explains what it means in plain English using AI.
Browse the category
All 10 finance calculators
Each calculator runs in your browser instantly and works without sign-up. Tap any card to start.
Mortgage calculator UK
Monthly payment, total interest, stamp duty for England, Scotland, and Wales, plus the 4.5× affordability check.
Try itLoan calculator
Work out monthly repayments and total interest on personal loans, secured loans, and any fixed-rate borrowing.
Try itCompound interest
Project how a lump sum or regular savings grow over years with compounding interest, after inflation if you choose.
Try itInvestment return (CAGR)
Annualised growth rate of an investment between two dates. Compare funds, stocks, or property over different timeframes.
Try itRetirement calculator
Project your pension pot based on contributions, expected growth, State Pension, and your target retirement age.
Try itSavings goal
How much to put away each month to reach a target — house deposit, wedding, car, or any savings goal.
Try itCurrency converter
Convert between GBP, USD, EUR, and 30+ currencies using daily rates from the European Central Bank.
Try itIncome tax UK
Estimate your PAYE income tax and National Insurance for the 2025/26 tax year, including dividend and personal allowance.
Try itVAT calculator UK
Add or remove 20% standard VAT, 5% reduced rate, or zero-rated. Handy for invoices, receipts, and price quotes.
Try itSalary take-home UK
Convert gross salary to monthly take-home pay after Income Tax, NI, and optional pension contributions.
Try itAbout our UK finance calculators
Calclens’ finance calculators are built for UK-specific decisions — mortgages, loans, pensions, tax, and investments. Every formula traces back to an authoritative UK source: HMRC for tax rates and PAYE, the Financial Conduct Authority (FCA) for mortgage and lending guidance, the Bank of England for base-rate context, and the Office for National Statistics (ONS) for benchmark figures.
What sets Calclens apart from a standard mortgage calculator is the AI explanation layer. Once you’ve got the number, you can tap “Explain with AI” and get a plain-English summary of what it means — how your figure compares to UK norms, what would change it most, and one practical insight you can act on. The calculation itself is always free and runs instantly in your browser.
Who these calculators are for
The finance category covers the four most common UK money decisions:
- Buying a home — mortgage payments, stamp duty for England (SDLT), Scotland (LBTT), and Wales (LTT), and the 4.5× income affordability rule.
- Borrowing money — personal loans, secured loans, and the true cost of borrowing once interest is added.
- Saving and investing — compound interest projections, CAGR for comparing investments, and goal-based monthly savings targets.
- Pay and tax — gross-to-net salary conversion, PAYE income tax, National Insurance, VAT for businesses and freelancers, and pension projections.
Each calculator works on its own. You can also chain them — calculate your take-home pay first, then use that figure as input for what you can afford on a mortgage, then check whether the deposit you’re saving will hit your goal.
Common questions
Are these calculators specific to the UK?
Yes. Currency is GBP throughout, tax rates use HMRC bands for 2025/26, mortgage stamp duty covers all three UK systems (SDLT, LBTT, LTT), and pension figures use UK State Pension and tax relief rules. Some calculators (compound interest, CAGR, currency converter) are region-neutral and work for any country.
Do you store the numbers I enter?
No. The calculation runs in your browser and your figures don’t leave your device unless you tap “Explain with AI”, in which case the numbers (without your identity) are sent to our server to generate the explanation. See the privacy policy for the full picture.
How often are the tax and rate figures updated?
Tax-year-sensitive calculators (Income Tax UK, Salary Take-Home UK, VAT UK, Stamp Duty in the Mortgage calculator) are reviewed before the start of each UK tax year on 6 April, and again in November if an autumn budget changes the rates. Each calculator page shows its last-updated date.
Can I rely on these for actual financial decisions?
Calclens is an information tool, not financial advice. The numbers are accurate to the formulas and current UK rates, but real-world decisions involve more than the inputs we ask for — your full circumstances, credit history, lender criteria, and individual goals all matter. For decisions about borrowing, investing, or pensions, please consult an FCA-authorised adviser or get free guidance from MoneyHelper.