UK Mortgage Calculator

This calculator estimates the monthly payment on a UK repayment mortgage, along with the running costs of owning a home, and shows a full amortisation schedule. Enter the property price, your deposit, the term, and the interest rate to see the monthly figure, a cost breakdown, and how the balance falls over time. It is intended for buyers in the UK.

Getting ready to apply

UK lenders decide on affordability and risk, so a smooth application starts with the paperwork in order. It helps to have your last three years of addresses with no gaps, three months of income (payslips, or two to three years of accounts or SA302s if you are self-employed), and three months of bank statements. Bring details of any loans and credit cards too. Check your credit file first and query anything wrong before you apply, because a lender pulls the same record. With solid credit you can borrow with a small deposit: many products accept 5% of the property value, and some 95% mortgages are supported by the government's mortgage guarantee scheme, though the exact deals move with the market.

Deposit and loan-to-value

Your deposit sets your loan-to-value ratio (LTV), the size of the loan against the property price. A 10% deposit means a 90% LTV loan. LTV drives the rate you are offered: the lower it is, the cheaper the deal, with the best rates usually reserved for 60% LTV or below. A 5% deposit is the common minimum, but it lands you in the highest-rate bands and leaves little cushion if prices dip. The larger the deposit, the smaller the loan, the lower the monthly payment, and the less interest you pay across the term.

Repayment or interest-only

Most UK residential mortgages are repayment (capital and interest): each monthly payment covers the interest plus a slice of the balance, so the loan clears by the end of the term. This calculator models a repayment mortgage. The alternative, interest-only, pays just the interest each month and leaves the full balance due at the end, which then has to be repaid from a separate plan such as investments or a sale. Interest-only is now mostly limited to higher-earning borrowers and buy-to-let landlords, because of the risk of reaching the end of the term with the debt still outstanding.

Fixed, tracker, and variable rates

UK deals come in a few shapes. A fixed rate holds the same interest for a set period, commonly two, three, five, or ten years, giving a payment that never moves during the deal. Variable rates change, and they take several forms. A tracker follows an external rate, usually the Bank of England base rate, plus a fixed margin, so it falls and rises with the base rate; introductory tracker rates can be among the lowest on offer, but they can climb just as easily. A discount rate sits a set amount below the lender's standard variable rate. The standard variable rate (SVR) is the lender's default rate, which you roll onto when a fixed or tracker deal ends, and it is usually higher, which is why many borrowers remortgage at that point. Most deals carry an early repayment charge (ERC) if you overpay heavily or leave during the deal period.

Flexible features

A flexible mortgage adds room to move. Overpayments let you pay the loan down faster, as regular extra amounts or lump sums, cutting the interest and shortening the term. Underpayments let you pay less than the normal amount for a while, and a payment holiday lets you pause payments for a short stretch, sometimes up to six months. These options usually come with conditions and can carry charges, and many standard mortgages already allow overpayments of up to 10% of the balance a year without penalty, so it pays to compare before choosing a product for flexibility alone.

How long the term runs

The term is the total time to repay. The traditional length is 25 years, but 30, 35, and even 40-year terms are now common, especially for younger buyers stretching the payment to afford a home. A longer term lowers the monthly payment but raises the total interest, because the balance is paid down more slowly. A shorter term does the reverse. Try a few term lengths in the calculator and compare the total interest before you decide.

Affordability and the stress test

UK lenders do not lend on the headline payment alone. Since the mortgage rules were tightened in 2014, they assess affordability against your income and outgoings and stress-test the loan, checking that you could still pay if rates rose. Borrowing is typically capped around 4 to 4.5 times income, though some lenders stretch to 5.5 times for stronger applicants. The result is that the amount you can borrow is usually smaller than the raw payment suggests. To gauge a price range against your income first, our House Affordability Calculator can help.

Stamp Duty Land Tax (SDLT)

Buying a home in England or Northern Ireland means paying Stamp Duty Land Tax, charged as a percentage of the price in bands, so you pay each rate only on the part of the price that falls in that band. The current standard rates are:

First-time buyers pay no SDLT on the first £300,000 and 5% on the portion from £300,001 to £500,000, with no relief once the price passes £500,000. An extra surcharge (currently 5%) applies to additional properties such as second homes and buy-to-lets. Scotland and Wales run their own versions instead, Land and Buildings Transaction Tax and Land Transaction Tax, with different bands. Special rules cover shared ownership, company purchases, and bulk buys, so it is worth checking the exact figure or taking advice before you commit.

Remortgaging and moving

When a fixed or tracker deal ends you usually remortgage, taking a new deal with your lender or another one, to avoid slipping onto the higher standard variable rate. Remortgaging can also release equity or change the term. If you move mid-deal, many mortgages are portable, letting you carry the rate to the new property, though you re-qualify on affordability. To compare the cost of switching to a new rate, our Refinance Calculator lays out the monthly and lifetime numbers.

How this calculator works

Enter the property price and your deposit as a percentage or a cash amount, and the tool computes the loan, applies the interest rate monthly, and returns the monthly capital-and-interest payment. Turn on the optional costs to add property costs, buildings insurance, any service charge, and other running costs, and the total updates as you type. The cost-breakdown chart splits the lifetime total into capital, interest, and each recurring cost, while the balance chart shows the debt falling across the term. The summary lists the loan amount, the total of all payments, the total interest, and the payoff date. Use the amortisation schedule to see the balance year by year.

The stamp duty bands in force

Stamp Duty Land Tax applies in England and Northern Ireland and is charged in slices, so each rate applies only to the part of the price inside its band. The current bands took effect on 1 April 2025, when the temporary higher thresholds ended.

First-time buyers pay nothing up to £300,000 and 5% on the portion from £300,001 to £500,000. The relief disappears completely above £500,000, so a first-time buyer at £505,000 pays the standard rates on the whole price. That cliff edge is worth knowing before making an offer just over the line.

Scotland and Wales run separate taxes with their own bands, Land and Buildings Transaction Tax and Land Transaction Tax, so a purchase there is not covered by the figures above.