Orbit
HomeDealsBlog
Resources
ToolsCancel HubSubscription DealsCompareNews
Get Started →
UK mortgage calculator

Mortgage Repayment Calculator UK

Work out your monthly mortgage payments, the total interest and the total cost over the full term. Repayment or interest-only, any rate and term. Free, no signup.

Free, no signupRepayment or interest-onlyTotal interest shown
Your mortgage
How much you're borrowing
£
Your annual rate (% APR)
%
Most UK mortgages run 25 to 30 years
yrs
Your repayment
£1,389.58/month
Repayment mortgage over 25 years£166,874 total interest
10y20y
Repayment (capital & interest): the balance falls to zero over the term.
Amount borrowed£250,000
Repayment per month£1,389.58
Number of repayments300
Total interest£166,874
Total repaidCapital plus interest over the full term£416,874
Repayment by frequency
FrequencyRepaymentTotal interest
monthly£1,389.58£166,874
fortnightly£641.00£166,647
weekly£320.42£166,550
Each frequency is worked out on its own true period, so fortnightly is not the monthly figure halved. Most UK lenders collect monthly, though some allow weekly or fortnightly.
Want to clear it sooner?
Overpaying, even a small amount each month, comes straight off the capital and cuts the interest on every payment after it. See the effect with the mortgage overpayment calculator.
Estimate only. Assumes a fixed rate for the full term and excludes fees, product changes and rate changes. A guide, not financial advice.
Simon Chadwick
Simon Chadwick
Founder, Orbit Money
Method: standard amortisation formulaUpdated: 16 July 2026Sources: MoneyHelper, Bank of England

How your mortgage repayment is worked out

A repayment mortgage, also called capital and interest, uses the standard amortisation formula. Each monthly payment covers the interest charged on the balance for that month, and whatever is left over reduces the capital. Because the balance shrinks over time, the interest portion of each payment falls and the capital portion rises. The formula that ties it together is payment = P × r ÷ (1 − (1 + r)−n), where P is the amount borrowed, r is the monthly interest rate, and n is the total number of payments. This mortgage payment calculator applies it for monthly, fortnightly and weekly payments.

Loan amount or property price and deposit

You can enter the amount you are borrowing straight into the calculator, or switch to property price and deposit and let it work out the loan for you. Entering a price and deposit also shows your loan to value, or LTV, which is the loan as a percentage of the property price. LTV matters because lenders price their deals in bands: a bigger deposit drops you into a lower LTV band, which usually means a lower interest rate and a smaller monthly payment.

Repayment vs interest-only

A repayment mortgage clears both the interest and the capital, so the balance reaches zero and you own the home at the end of the term. An interest-only mortgage covers just the interest, so the monthly payment is lower but the full amount borrowed is still owed when the term ends and has to be repaid another way. Interest-only lending is now mostly limited to buy-to-let and some later-life products. Toggle between the two above to see the gap for your own mortgage.

A worked example

Take a £250,000 mortgage at 4.5% over 25 years, paid monthly. The monthly rate is 4.5% ÷ 12 = 0.375%, over 300 payments, which gives a payment of about £1,390 a month. Across the full term that adds up to roughly £416,700 repaid, of which around £166,700 is interest. Shorten the term or lower the rate and the total interest drops sharply, which is why the term and rate matter as much as the amount you borrow.

What the calculator leaves out

This is a clean estimate of the payment on the amount borrowed. It assumes a single rate for the whole term, so it does not model the jump from a fixed deal onto a standard variable rate, or a later remortgage. It also excludes arrangement fees, valuation and legal costs, buildings insurance and any product fee added to the loan. Treat the figure as the core monthly payment and add those separately.

Frequently asked questions

How are mortgage repayments calculated?
A repayment (capital and interest) mortgage uses the standard amortisation formula: repayment = P × r ÷ (1 − (1 + r)^−n), where P is the amount borrowed, r is the interest rate for one period, and n is the total number of payments. Interest is charged on the balance still owing, so early payments are mostly interest and later ones are mostly capital. This calculator applies that formula for you and shows the total interest over the full term.
What is the difference between a repayment and interest-only mortgage?
A repayment mortgage pays off both the interest and the capital, so the balance reaches zero by the end of the term and you own the home outright. An interest-only mortgage covers just the interest each month, so the payments are lower but the full amount borrowed is still owed at the end and has to be repaid another way. Interest-only is now mostly limited to buy-to-let and some later-life lending. Switch between the two above to compare.
How much can I overpay on my mortgage?
Most UK lenders let you overpay up to 10% of the outstanding balance each year without an early repayment charge, though the exact limit is set in your mortgage terms. Overpayments come straight off the capital, so every future interest charge is worked out on a smaller balance. Even modest regular overpayments can take years off the term and save a large amount of interest. Check your annual allowance before making a lump-sum overpayment.
What happens to my repayments when my fixed rate ends?
When a fixed deal ends you usually move onto the lender's standard variable rate (SVR), which is often higher, so your monthly payment can jump. Many borrowers remortgage to a new deal before that happens to keep the payment down. To see the impact, put your current rate into the calculator, then the SVR or a new deal's rate, and compare the two monthly figures.
How much interest will I pay over the life of the mortgage?
On a £250,000 repayment mortgage at 4.5% over 25 years, the monthly payment is about £1,390 and the total interest comes to roughly £166,700. The total interest depends heavily on the rate and the term: a shorter term means higher monthly payments but far less interest overall. The calculator shows your total interest and total repaid as soon as you enter your figures.
Does the mortgage term change my monthly payment?
Yes, and by a lot. A longer term spreads the capital over more payments, so each monthly payment is lower, but you pay interest for longer and the total interest is higher. A shorter term does the opposite: higher monthly payments, far less interest in total. Try 25, 30 and 35 years in the calculator to see the trade-off for your own figures.

Related tools

Mortgage Overpayment Calculator
See how overpayments cut your interest and clear the mortgage sooner.
Stamp Duty Calculator (UK)
Work out the stamp duty on your property purchase across the UK.
Loan Repayment Calculator (UK)
Work out monthly payments and total interest on any personal loan.
Budget Calculator
Check how the repayment fits your monthly budget.

More budgeting & savings calculators

Interest-Only Mortgage Calculator
Work out your monthly interest-only payment, the total interest over the term, and the capital still owed at the end. Compare it with a repayment mortgage.
Mortgage Repayment Calculator (AU)
Work out your home loan repayments monthly, fortnightly or weekly, plus the total interest over the life of the loan. Principal & interest or interest-only.
Car Finance Calculator (UK)
Work out your monthly car finance payment on HP or PCP, with total interest, total payable and the PCP balloon payment. UK APR, no signup.
Rental Yield Calculator (UK)
Enter a property value and the rent to get the gross and net rental yield, annual rent and net income. Running costs included.
Loan to Value Calculator (UK)
Work out your LTV from your property value and deposit or loan. See your equity in pounds and per cent, and which lender rate band you fall in.
ISA Calculator
Project your tax-free ISA growth. Enter contributions, expected return and years to see what your Stocks & Shares or Cash ISA could be worth.

Your mortgage is the big one. The small drains add up too.

Orbit finds every subscription and recurring charge leaving your account and puts them in one place, so more of your money goes on the mortgage.

Try Orbit free
Simon Chadwick
About the author
Simon Chadwick
Founder of Orbit Money

Simon is the founder of Orbit Money, a tool that helps people track subscriptions and recurring spend. He builds Orbit's free money calculators and writes about personal finance for UK and Australian readers.

More from Simon →
This tool is a guide, not financial advice.