Mortgage Calculator (UK)
Estimate the monthly cost of a UK repayment mortgage from your property price, deposit, interest rate and term.
Example
On a £300,000 property with a £30,000 deposit (10%), you borrow £270,000. At 4.5% over 25 years (300 months) the monthly payment is about £1,500.75. Over the full term you repay roughly £450,224, of which around £180,224 is interest.
How it works
Enter the property price, deposit, annual interest rate and term in years. The tool computes the loan amount and uses the standard amortisation formula to show your monthly payment, total interest and total amount repaid.
Good to know
This UK mortgage calculator turns four numbers — property price, deposit, annual interest rate and term in years — into the figures that actually matter when you are budgeting for a home: your monthly repayment, the loan amount after your deposit, the total interest you will pay, and the total amount repaid over the life of the mortgage. It also shows your loan-to-value (LTV) percentage and a visual split between capital and interest, all calculated instantly in your browser as you type.
It is built for UK buyers and remortgagers in GBP who want a quick, private sanity-check before talking to a broker or lender, or who are comparing scenarios such as a bigger deposit, a different rate, or stretching the term from 25 to 30 years. It models a capital-and-interest (repayment) mortgage at a single fixed rate for the whole term, so it suits standard residential repayment deals rather than interest-only or buy-to-let arrangements.
When reading the result, treat the monthly payment as the headline budgeting number and the total interest as the long-term cost of borrowing. A useful habit is to compare two figures side by side: notice how a small change in rate or a few extra years on the term barely moves the monthly payment but can add tens of thousands to total interest. The LTV figure matters too — it is the share of the price you are borrowing, and lower bands (for example dropping below 90%, 85% or 80%) often unlock cheaper rates.
One caveat: this is an estimate that assumes the same rate for the entire term, which rarely happens in the UK because most deals are fixed for an initial period (often 2 or 5 years) and then revert to a higher standard variable rate. It also excludes arrangement fees, valuation costs, Stamp Duty and insurance. Use the output to compare options and frame questions, then rely on an official lender illustration for the binding numbers.
Frequently asked questions
Is this a repayment or interest-only mortgage?
It models a capital-and-interest (repayment) mortgage, where each monthly payment clears both interest and part of the loan so the balance reaches zero by the end of the term. Interest-only mortgages, where you pay only interest each month, are not covered here.
What deposit and LTV should I aim for in the UK?
Most UK lenders want at least a 5–10% deposit. A larger deposit lowers your loan-to-value (LTV) ratio, which usually unlocks better interest rates. This tool shows your LTV so you can see how increasing the deposit reduces the amount borrowed and your monthly cost.
Is my data uploaded anywhere?
No — this calculator runs entirely in your browser; nothing is uploaded.
Is this financial advice?
No. These are educational estimates — consult a qualified financial professional before making decisions.
People also ask
How much can I borrow for a mortgage in the UK?
UK lenders typically lend around 4 to 4.5 times your annual income, though some go higher for certain borrowers, and the exact figure depends on your deposit, outgoings, credit history and affordability checks. This calculator does not assess borrowing limits; it works out repayments once you already know the loan amount.
What is a good interest rate on a UK mortgage right now?
Mortgage rates change frequently and vary by lender, deal length, and your loan-to-value band, so the most competitive rate is whatever is currently on offer for your LTV and fixed period. Lower LTV bands generally attract lower rates.
How does the deposit affect my monthly mortgage payment?
A larger deposit reduces the loan amount, which lowers both the monthly payment and the total interest, and it cuts your loan-to-value ratio so you may also qualify for a cheaper rate. You can test this directly by raising the deposit figure and watching the loan, payment and LTV update.
Should I choose a 25-year or 30-year mortgage term?
A longer term lowers the monthly payment but increases the total interest paid because you are borrowing for longer, while a shorter term costs more each month but less overall. Entering both terms in the calculator shows the trade-off in pounds for your specific figures.
What is loan-to-value (LTV) and why does it matter?
LTV is the percentage of the property price you are borrowing after your deposit, so a £270,000 loan on a £300,000 home is 90% LTV. Lenders price risk using LTV bands, and crossing into a lower band such as 85% or 80% can give access to better interest rates.
Does this calculator include Stamp Duty, fees, or insurance?
No. It calculates only the repayment mortgage itself based on the loan, rate and term, and excludes Stamp Duty, arrangement and valuation fees, buildings insurance and any product fees. Those costs should be budgeted for separately.
Why does a fixed-rate mortgage estimate differ from what I actually pay?
This tool assumes one rate for the whole term, but most UK deals fix the rate only for an initial period and then move to a higher standard variable rate, and real payments also reflect fees and rounding. Treat the figures as a planning estimate, not a guaranteed quote.
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