Mortgage Payment Calculator
Work out your monthly mortgage payment, total interest, and loan-to-value ratio — and see how overpaying could shorten your term and save you thousands.
Your monthly payment (P+I)
£1,169.18
You'll pay £1,169.18 per month for 25 years. Your loan-to-value ratio is 80.0%. Over the life of the mortgage you'll pay £150,754.02 in interest on top of the £200,000.00 you borrowed.
Balance and interest over time
Year-by-year breakdown
| Year | Payments | Interest | Principal | Balance |
|---|---|---|---|---|
| 1 | £14,030.16 | £9,906.35 | £4,123.81 | £195,876.19 |
| 2 | £14,030.16 | £9,695.37 | £4,334.80 | £191,541.39 |
| 3 | £14,030.16 | £9,473.59 | £4,556.57 | £186,984.82 |
| 4 | £14,030.16 | £9,240.47 | £4,789.70 | £182,195.12 |
| 5 | £14,030.16 | £8,995.42 | £5,034.74 | £177,160.38 |
Formula
A standard amortising mortgage uses the same formula as any other fixed-rate loan:
M = P × r(1+r)n / ((1+r)n − 1),
where P is the loan amount (home price minus deposit), r is
the monthly rate (annual rate divided by 12), and n is the term in months.
With a 25- or 30-year term this means early payments are mostly interest and later payments
are mostly principal — the chart above shows the crossover. Optional taxes and insurance are
added directly to the monthly outflow without affecting the schedule.
When this calculator helps
Buying a home in the UK means turning an asking price into a monthly figure you can actually live with, and that is exactly what this calculator does. Give it the property price, your deposit, an interest rate and a term, and it returns the monthly principal and interest payment along with the total interest over the life of the loan and your loan-to-value ratio. It is built for the planning stage — sizing up what you can afford, comparing a 25-year term against a 30, or checking whether a bigger deposit brings the payment within reach.
It is most useful before you have an agreement in principle, when the questions are still open: how much would a £250,000 house actually cost each month, does saving another £10,000 of deposit make a meaningful difference, how much extra would a slightly higher rate add. Because you can also add an overpayment, you can see how chipping away at the balance shortens the term and cuts the interest bill.
How to read your result
The headline figure is your monthly principal and interest — the core mortgage payment. The total interest figure shows what the loan costs you on top of the amount borrowed across the whole term, and it is usually larger than first-time buyers expect, because interest compounds over decades. The loan-to-value ratio (your loan as a percentage of the property price) matters too: a lower LTV generally unlocks better rates from UK lenders.
Term and rate trade off against each other. A longer term lowers the monthly payment but raises the total interest, because you are borrowing for longer; a shorter term does the opposite. Even a fraction of a percent on the rate moves both numbers noticeably over 25 or 30 years. Remember this is principal and interest only — it does not include council tax, buildings insurance, ground rent or service charges, which UK borrowers pay separately.
A worked example
Suppose you are buying a £250,000 home with a £50,000 deposit, leaving a £200,000 mortgage at 5% over 25 years. The monthly principal and interest comes to roughly £1,169, and over the full term you would pay around £150,000 in interest on top of the £200,000 borrowed. Your loan-to-value starts at 80%. Add a £100 monthly overpayment and you would clear the mortgage several years early and save a meaningful chunk of that interest — the calculator shows exactly how much.
Common mistakes to avoid
Most nasty surprises come from treating the calculator's payment as the whole cost of owning, or from assuming today's deal lasts the whole term.
- Forgetting the one-off costs — Stamp Duty Land Tax, valuation and legal fees, and survey costs sit outside the monthly payment and can run to thousands.
- Assuming your fixed-rate deal lasts the full term; most UK fixes run 2 or 5 years, then revert to the lender's higher SVR unless you remortgage.
- Leaving out council tax and buildings insurance, which UK lenders do not bundle into the payment but which you still have to pay every month.
- Overpaying past your annual penalty-free allowance (often 10%) and triggering an early repayment charge.
How UK mortgages actually work
The UK market is built around short fixed periods rather than long ones. Most borrowers take a 2-year or 5-year fixed rate on a 25-to-35-year mortgage, and when that fix ends the loan reverts to the lender's standard variable rate (SVR), which is typically well above headline deals. That is why remortgaging every few years is a national habit — staying on the SVR usually means paying more than you need to. This calculator assumes one steady rate for the whole term, so for a realistic picture, re-run it with the SVR or a likely future rate to see what the payment could look like after your fix ends.
Affordability is also lender-led: UK banks generally cap lending at around 4 to 4.5 times income and stress-test you against higher rates before approving. And remember Stamp Duty — a one-off tax on the purchase price above set thresholds — which can add several thousand pounds to the cost of moving and is entirely separate from the monthly payment this calculator produces.
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Frequently asked questions
What's the difference between fixed-rate, tracker, and SVR mortgages?▾
A fixed-rate mortgage locks your interest rate for a set period (typically 2, 5, or 10 years), then reverts to the lender's standard variable rate (SVR) unless you remortgage. A tracker follows a benchmark rate (usually the Bank of England base rate) plus a margin, so your payment moves up and down with it. SVR is the lender's default rate after a fixed or tracker deal ends — usually higher than headline rates, which is why most borrowers remortgage. This calculator assumes a single fixed rate for the full term.
Does this calculator include stamp duty or other purchase costs?▾
No — those are one-time costs, not part of your monthly payment. We're planning a separate Stamp Duty Calculator (UK-specific because rates and thresholds change with the Budget). For now, treat your mortgage payment and your purchase costs as two separate budgets.
What about council tax and buildings insurance?▾
In the UK, council tax and buildings insurance are typically paid separately from the mortgage — your lender doesn't bundle them. Leave the 'Annual property tax' and 'Annual insurance' fields at 0 unless you specifically want to model them as part of your monthly outflow. The optional 'Tax & insurance' section is most useful for users in markets that bundle these costs.
How much can I borrow on my income?▾
Most UK lenders cap mortgages at 4–4.5× your annual income, sometimes stretching to 5× for strong applicants or specific schemes. Your actual offer depends on your credit history, deposit size, monthly outgoings, and the lender's stress-test of higher rates. This calculator works the other way — you tell it the loan amount and it tells you the payment. For an income-led estimate, use a separate affordability calculator or speak to a broker.
Should I overpay my mortgage?▾
Often yes — overpayments hit principal directly, so they save compound interest over the remaining term. Most fixed-rate UK mortgages allow overpayments of up to 10% of the outstanding balance per year without penalty; check your agreement before exceeding that. The 'Extra monthly payment' field above shows the impact in months saved and interest saved.