Mortgage calculators

These free UK mortgage calculators cover the main questions: how much you can borrow (employed or self-employed), what a buy-to-let or let-to-buy allows, and the cost of interest-only, offset, repayment, remortgage, stamp duty and bridging. Every calculator shows its formula and a worked example, so the number is never a black box. They are indicative, not a quote, and for a real figure you need a regulated broker.

How much can I borrow

Affordability calculator Your indicative borrowing range from income, and how the stress test and debts change it. Self-employed calculator How lenders read one year, two years or the lower figure, and the spread it creates. Mortgage readiness check A quick self-check of where your case sits, plus the full readiness check.

Buy-to-let and moving

Buy-to-let calculator How much the rent supports, using the rental cover (ICR) stress test, not your income. Let-to-buy calculator Release a deposit from your current home to buy the next one, keeping the old one let. Rental yield calculator The gross and net yield on a rental, and what a good yield looks like. Bridging loan calculator What short-term bridging finance really costs once fees and monthly interest are counted.

Rate and product type

Repayment calculator Monthly payment and total interest on a repayment mortgage. Interest-only calculator The lower monthly cost, and the balance still owed at the end. Offset calculator What linking your savings to the mortgage saves you, tax-free. Overpayment calculator How overpaying cuts the term and the total interest. Loan-to-value calculator Your LTV, and the bands where better rates open up.

Remortgage and costs

Remortgage calculator What a new rate would do to your monthly payment. Switch or stay tool Remortgage elsewhere versus a product transfer with your current lender. Payment shock calculator What your payment becomes when a cheap fixed rate ends. Early repayment charge The ERC for leaving a deal early, and when it is worth paying. Stamp duty calculator Stamp duty on your purchase, including the first-time buyer and second-home rules. Porting calculator Taking your current rate to a new property, and the sums that decide it.

Common questions

Which mortgage calculator do I need?

Start with what you are trying to answer. To find your budget, use the affordability calculator, or the self-employed one if your income is from a business. For a rental, use the buy-to-let calculator, which works from the rent rather than your income. If you are moving but keeping your home, use let-to-buy. To compare deals, use the repayment, offset or remortgage calculators. Each page shows the formula and a worked example, so the number is never a black box.

Are these calculators a mortgage quote?

No. They are indicative tools that show how the sums work, using general figures. Your real numbers depend on the lender, the affordability stress test, your credit profile and the property. When you want a real figure, a regulated broker can confirm it. The calculators are information, not advice.

Do I have to give my email to use them?

No. The instant calculators run in your browser and store nothing. Some pages also embed a fuller third-party tool run by Propillo, but the basic working is always free and ungated.

Ready to talk to someone? See how to choose a mortgage broker.

Adam Parker

Founder, MortgageExplained

Adam spent over eight years as a mortgage adviser at Just Mortgages, with further experience in commercial finance. He is CeMAP and CF qualified. He built MortgageExplained to do one thing well: explain mortgages in plain English, so you know where you stand before you speak to a regulated broker. Every page on the site is written by Adam.

Last reviewed: 25 July 2026