Mortgage Calculator
Use this mortgage calculator to find your monthly payment, loan-to-value and total interest from the price, deposit, rate and term.
Quick answer: The monthly payment on a repayment mortgage depends on the loan, the interest rate and the term. A £250,000 mortgage at 4.5% over 25 years costs £1,389.58 a month. Enter the property price, deposit, rate and term in the calculator to see your own payment, total interest and a year-by-year balance table.
How do you use the Mortgage Calculator?
- Enter price and deposit. Type the property price and the deposit you can put down; the loan amount and loan-to-value are worked out for you.
- Enter the rate and term. Add the annual interest rate and the length of the mortgage in years.
- Press Calculate. Read the monthly payment, total interest and the yearly balance table, and add running costs if you want the full monthly figure.
What is the formula, and what does a worked example look like?
Formula: Payment = L × r ÷ (1 − (1 + r)^−n), with r = annual rate ÷ 12 and n = years × 12. Loan-to-value = loan ÷ price.
Example: £350,000 price, 15% deposit, 4.5% over 30 years: loan £297,500, payment about £1,507.39, total interest about £245,160. (Figures in GBP for UK mode; switch to US mode for dollars and a down payment.)
Method & source: Standard fixed-rate repayment (amortisation) formula. See how we test our calculators.
Next step: try loan repayments with extra payments or UK take-home pay.
Worked examples for the Mortgage Calculator
Each figure below was produced by the same code as the calculator, so you can enter the inputs and get the same result. Rates and thresholds are the ones on the official pages linked under “How it is calculated”.
£300,000 home, £60,000 deposit, 4.5%, 25 years
Repayment mortgage at an example rate; check live rates with lenders.
- Loan: £240,000 (80.0% loan-to-value).
- Monthly repayment: £1,334.00 for 300 months.
- Total interest over the term: £160,199.
Result: £1,334.00 a month; £400,199 repaid in total.
Same loan over 30 years instead of 25
A longer term lowers the payment but costs more interest.
- Monthly repayment: £1,216.04 (£117.95 less).
- Total interest: £197,776 (£37,577 more).
Result: Five extra years add £37,577 of interest for a £117.95 lower payment.
$400,000 home, $80,000 down, 6.5%, 30 years, with taxes and insurance
Property tax $4,800 and insurance $1,500 a year are example figures; both vary widely.
- Loan: $320,000 (80.0% loan-to-value).
- Principal and interest: $2,022.62.
- Tax and insurance add $525.00 a month, so the all-in payment is $2,547.62.
Result: $2,547.62 a month; $408,142 of interest over 30 years.
How is the Mortgage Calculator calculated, and where do the rates come from?
The monthly repayment is the loan amount (price minus deposit) put through the same annuity formula as any amortising loan: payment = L × r ÷ (1 − (1 + r)^−n), with r the annual rate divided by 12 and n the number of months. Each year's table splits the payments into interest and capital, so you can see how slowly the balance falls in the early years.
The loan-to-value ratio is the loan divided by the price. It matters because lenders price their rates in bands of LTV; a bigger deposit often unlocks a lower rate. Property tax, insurance and other monthly costs are added after the repayment, which is how a US lender's 'PITI' figure is built.
The result does not include arrangement fees, valuation costs or legal fees. In England and Northern Ireland, Stamp Duty Land Tax is a separate one-off cost: GOV.UK lists 0% up to £125,000, 2% to £250,000, 5% to £925,000, 10% to £1.5 million and 12% above for a main home, with a higher threshold for first-time buyers. In the US, the CFPB's guidance on the Loan Estimate shows how to compare the real cost of offers.
- GOV.UK – Stamp Duty Land Tax residential rates – SDLT bands for main homes and first-time buyers in England and Northern Ireland; it is a separate cost from the mortgage payment.
- CFPB – Owning a home – US guidance on comparing Loan Estimates, understanding closing costs and shopping for a mortgage.
What are the common mistakes and edge cases?
- Quoting only the repayment. Fees, SDLT or closing costs, a valuation and moving costs come on top of the deposit.
- Comparing mortgages of different terms by payment alone. A 30-year payment is lower than a 25-year one, but the total interest is higher.
- Assuming the rate is fixed for the whole term. UK deals often fix for 2 to 5 years and then revert; US adjustable-rate loans reset. Recalculate when the rate changes.
- Leaving out property tax and insurance in a US estimate. They can add hundreds of dollars a month and may be collected through escrow.
- Using an interest-only assumption. This calculator models a repayment mortgage where the balance is paid down to zero.
More in this category: Savings & Loans calculators.
How are mortgage payments calculated?
A mortgage calculator estimates the regular payment on a home loan from the property price, your deposit, the interest rate and the length of the mortgage. It also shows how much interest you will pay in total and how quickly the balance falls.
This mortgage calculator for your monthly payment uses a standard repayment (capital and interest) mortgage, offers UK and US wording, and lets you add running costs such as insurance so you can see the full monthly picture.
How do you get from loan amount to monthly payment?
Enter the price, your deposit or down payment as an amount or a percentage, the rate and the term.
- Loan amount: property price minus deposit, with the loan-to-value percentage shown.
- Monthly payment: the fixed instalment that repays the loan exactly over the term.
- Total interest: the extra you pay on top of the amount borrowed over the whole term.
- Rate check: a small table shows the payment if the rate is 1% lower, 1% higher or 2% higher.
- Yearly table and chart: interest paid, capital repaid and remaining balance for every year.
The payment shown is for capital and interest. Fees, taxes and rate changes after an initial fixed period are not included, so treat the result as a planning estimate.
Why does calculating your mortgage matter?
A mortgage is usually the largest debt you will take on. A few minutes of maths before you commit can save thousands.
- Find out what monthly payment fits your budget before house-hunting.
- See how a bigger deposit lowers both the payment and the total interest.
- Compare a shorter term with a longer one and the interest each costs.
- Stress-test your budget against higher interest rates.
- Understand how slowly the balance falls in the early years.
Use a mortgage calculator early, then confirm figures with a lender or independent adviser before you make an offer.
Worked walkthrough: a £350,000 home
Suppose a property costs £350,000 and you put down 15% (£52,500). The loan is £297,500, an 85% loan-to-value. At 4.5% over 30 years the monthly payment is about £1,507.39, and total interest over the term is roughly £245,160, so you repay about £542,660 in all. The rate table shows how sensitive this is: at 5.5% the payment rises to about £1,689.17, and at 3.5% it falls to about £1,335.91. The yearly table shows that in year one most of each payment is interest, with the capital share growing each year.
Things to check before you rely on a payment figure
- Do not stretch your budget to the maximum payment: leave room for maintenance, insurance and a rise in the interest rate.
- Compare a longer term with a shorter one. The longer term lowers the payment but usually costs far more interest overall.
- A larger deposit often reduces the interest rate you are offered as well as the amount borrowed – try 5%, 10% and 20% to see the effect.
- Check whether your lender allows overpayments and whether there is an early-repayment charge before assuming you can pay the loan off early.
- Remember the rate may change after an initial fixed or introductory period. Use the rate table to test a higher rate.
Repayment and interest-only mortgages
This calculator assumes a repayment mortgage, where each payment covers the interest and repays part of the loan, so the debt is cleared by the end of the term. On an interest-only mortgage you pay only the interest, and the full amount is still owed at the end. On a £200,000 loan at 5%, interest-only costs £833.33 a month, while a 25-year repayment mortgage costs £1,169.18 a month but leaves nothing owing. (Figures in GBP for UK mode; switch to US mode for dollars.)
The trade-off between term and cost
A longer term makes the monthly payment smaller but adds a lot of interest.
| Term | Monthly payment | Total interest |
|---|---|---|
| 20 years | £1,319.91 | £116,779 |
| 25 years | £1,169.18 | £150,754 |
| 30 years | £1,073.64 | £186,512 |
How sensitive the payment is to the rate
On £200,000 over 25 years the monthly payment is £1,055.67 at 4%, £1,169.18 at 5% and £1,288.60 at 6%, roughly £114 more for the step from 4% to 5% and £119 more from 5% to 6%. The rate table in the calculator shows the payment at a rate 1% lower, 1% higher and 2% higher, which is useful for stress-testing your budget before an introductory rate ends.
Deposit and loan-to-value
The deposit reduces the amount you borrow, and loan-to-value (LTV) expresses the loan as a share of the property price. A larger deposit lowers the payment and often qualifies for a better rate, which the calculator cannot know, so try a few scenarios. On a £300,000 property at 5% over 25 years:
| Deposit | Loan (LTV) | Monthly payment |
|---|---|---|
| 5% | £285,000 (95%) | £1,666.08 |
| 10% | £270,000 (90%) | £1,578.39 |
| 20% | £240,000 (80%) | £1,403.02 |
| 25% | £225,000 (75%) | £1,315.33 |
Where the first year’s payments go
Early payments are mostly interest. On the £200,000, 5%, 25-year example, the first 12 payments total about £14,030, of which about £9,906 is interest and only about £4,124 repays the loan, leaving £195,876 owed. The yearly table and chart show this shift, which is why overpaying early has the biggest effect.
What the payment does not include
The figure is a planning estimate for capital and interest. You can add insurance and other monthly costs, plus property tax in US mode, to see the payment with running costs. Fees, purchase taxes such as stamp duty, and rate changes after a fixed period are not included, and lender rules vary, so speak to a mortgage adviser before you commit – GOV.UK's guide to buying a home covers the wider process. To compare against other borrowing use the loan repayment calculator, to build a deposit use the savings goal calculator, and to see how money you set aside could grow, try the compound interest calculator.
Monthly payment on common mortgage sizes
Searching for a 120k mortgage calculator, a 150k mortgage or a 65,000 mortgage? The table shows the monthly repayment on six common mortgage amounts at an example rate of 4.5% a year, over 25 and 30 years, with the total interest over 25 years. It covers capital and interest only, so add buildings insurance and any other running costs.
| Mortgage amount | 25 years | 30 years | Interest over 25 years |
|---|---|---|---|
| £65,000 | £361.29 | £329.35 | £43,387 |
| £110,000 | £611.42 | £557.35 | £73,425 |
| £120,000 | £667.00 | £608.02 | £80,100 |
| £150,000 | £833.75 | £760.03 | £100,125 |
| £190,000 | £1,056.08 | £962.70 | £126,825 |
| £250,000 | £1,389.58 | £1,266.71 | £166,874 |
To work backwards from a monthly budget, divide the payment by the factor for your rate and term. At 4.5% over 25 years, a monthly payment of £1,000 supports a loan of about £179,910, £1,200 supports about £215,892, and £1,500 supports about £269,865, before any deposit is added to find the property price. Try your own rate, deposit and term in the calculator above.
Frequently Asked Questions (FAQs)
With the amortisation formula: payment = loan × r ÷ (1 − (1 + r)^−n), where r is the monthly interest rate and n is the number of monthly payments. The calculator does this for you.
Requirements vary by lender and country, and a larger deposit usually unlocks better rates. Try different percentages to see how the payment and loan-to-value change.
LTV is the loan as a percentage of the property price. Borrowing £240,000 against a £300,000 property is an 80% LTV. Lower LTVs often qualify for lower interest rates.
No. It assumes a repayment mortgage, where every payment covers interest and reduces the loan. Interest-only payments would be just the balance × the monthly rate.
Each month the lender charges interest on the balance still owed: the balance × the annual rate ÷ 12. The rest of the fixed payment repays the loan. On £200,000 at 5% over 25 years the payment is £1,169.18; in the first month £833.33 of it is interest and only £335.85 repays the loan. The next month the balance is a little lower, so slightly less interest is charged. That is why early payments are mostly interest.
At 4.5% over 25 years, a monthly repayment of £1,200 supports a loan of about £215,892, on capital and interest only. A higher rate or a shorter term supports a smaller loan. Enter your own rate, term and deposit in the calculator to find the monthly payment for a particular property price.
At 4.5% over 25 years, a £250,000 repayment mortgage costs about £1,390 a month. Change the rate, term or deposit to see your own figure.
Total interest is the sum of all payments minus the amount borrowed. Because interest is charged on the outstanding balance every month, over 25 years it can come close to the loan itself: £200,000 at 5% costs £150,754.02 in interest, or £350,754.02 in total. A shorter term or an overpayment reduces it. The calculator shows the total, together with a yearly table of interest, principal and balance.
Yes. Switch between UK (deposit) and US (down payment) wording and the same repayment maths applies.
Yes. Add insurance and other monthly costs (and property tax in US mode) and the calculator shows the payment plus running costs.
It is the loan divided by the property price, shown as a percentage. Lenders offer better rates at lower LTVs, so a larger deposit can reduce your monthly cost.
The calculator shows total interest for the term you enter. On the 25-year example above, interest is a large share of the amount repaid.
No. Stamp Duty Land Tax in England and Northern Ireland and US closing costs are one-off charges paid on top of the deposit; see the official links on this page for the rules.
Estimates only – not financial advice. Results assume a fixed rate for the whole term and a repayment (capital and interest) mortgage, with no fees, taxes or rate changes. Lenders’ offers and affordability rules differ. Speak to a lender or independent mortgage adviser before you borrow. See our full disclaimer.
Guides that use this calculator
- Mortgage Payments After the Bank Rate Rise: What 0.25% and 1% Cost per Month – Bank Rate hit 4% on 5 Nov 2026. On a £200,000, 25-year mortgage, +0.25% adds £29.32 a month and +1% adds £119.42. Tables and a free calculator.