Mortgage calculator
Every bank's calculator asks for your gross salary, applies a multiple, and hands back a borrowing limit. Nobody pays a mortgage out of gross pay. This one works out the payment and then shows it against the money that actually reaches your account, along with the LTV band you are being priced in and the purchase tax where you are buying.
Calculator
Mortgage calculator
20.0% of the price
£240,000 over 30 years at 4.65%
£1,237.53 a month
That is 41% of your £2,993.30 monthly take-home, leaving £1,755.77 for everything else.
What is your loan-to-value?
Your loan-to-value is 80.0% — the loan as a share of the purchase price.
Lenders price in bands, not on a sliding scale, so you are being quoted the 80% LTV rate. Another £15,000 of deposit would reach the 75% band and a better rate. Anything less than that changes nothing at all — which is why part of a deposit can be worth keeping back rather than rounding up.
£60,000 more would reach 60%, past which extra deposit stops improving the rate.
This loan is 5.3× your salary. Most lenders cap around 4.5×, though it is affordability rather than the multiple alone that decides an application.
What it costs to buy
| Property price | £300,000 |
| Deposit | £60,000 |
| Mortgage | £240,000 |
| Stamp duty (first-time buyer) | £0.00 |
| Cash needed on completion | £60,000.00 |
| Total interest over 30 years | £205,510.20 |
No stamp duty up to £300,000 and 5% from £300,001 to £500,000. Over £500,000 the relief is lost entirely, not tapered. Legal fees, a survey and moving costs typically add £2,000–£4,000 on top and are not included here. Stamp Duty Land Tax rates checked 2026-09-01 against HMRC. Your take-home is calculated with the standard 1257L code and no pension or student loan — adjust those on the main calculator if they apply, since both change what you can actually service.
Stretch the term, or overpay? Both, is usually the answer
A longer term buys a lower payment and costs more interest. What the headline comparison misses is that the extra interest only arrives if you actually take the longer term. Extend it, then overpay back to the £1,237.53 you would have paid over 30 years, and you clear the loan in much the same time for much the same total, with the lower payment left standing as a floor you can drop to in a bad month.
| Term | Monthly | vs 30 years | Total interest | If you overpay back |
|---|---|---|---|---|
| 30 years (now) | £1,237.53 | — | £205,510 | — |
| 32 years | £1,202.29 | -£35.24 | £221,678 | £205,510 over 30 yrs |
| 35 years | £1,158.21 | -£79.32 | £246,449 | £205,510 over 30 yrs |
| 37 years | £1,133.56 | -£103.97 | £263,299 | £205,510 over 30 yrs |
| 40 years | £1,102.20 | -£135.33 | £289,056 | £205,510 over 30 yrs |
The last column is the same longer term with £1,237.53 paid every month instead of the contractual minimum. Lenders typically allow overpayments of 10% of the balance a year without a charge, which on £240,000 is £24,000 and far above anything here. Check your own deal before relying on it, and remember the lower payment only helps if you do not spend the difference.
Why a bigger deposit sometimes buys you nothing
Lenders do not price on a sliding scale. They price in bands — typically 95%, 90%, 85%, 80%, 75% and 60% loan-to-value — and your rate is set by whichever band you land in. Going from 78% to 76% changes nothing. Going from 76% to 75% can change the rate on the whole loan. So the only deposit increases that pay for themselves are the ones that cross a boundary, and the sensible move is to work out where the next boundary is before deciding how much to put down.
The band that surprises people is the last one. 60% is normally the floor: below it lenders generally stop offering better pricing, so a 65% deposit and a 50% deposit are quoted much the same rate. Every pound past that point is capital locked into a house instead of sitting in reserve, and it buys no discount at all. That is worth knowing before emptying an ISA into a deposit.
Three different purchase taxes, not one
There is no single UK stamp duty. England and Northern Ireland charge Stamp Duty Land Tax, Scotland charges Land and Buildings Transaction Tax and Wales charges Land Transaction Tax. The thresholds differ, the rates differ, and so does first-time buyer treatment: England gives relief up to £500,000, Scotland lifts the nil-rate band by £30,000 instead, and Wales offers no relief at all because its £225,000 nil-rate band already applies to everyone. The calculator switches tax with the country you pick, so the figure is the one you would actually pay.
One trap worth naming: in England the first-time buyer relief is a cliff, not a taper. At £500,000 you pay £10,000. At £500,001 the relief vanishes entirely and the standard scale applies to the whole price, so a single extra pound of purchase price costs about £5,000 in tax. If you are negotiating near that line, it is worth knowing which side of it you want to be on.
What share of take-home is too much?
There is no official limit, and lenders test affordability rather than applying a ratio. As a rough shape, under 30% of take-home is comfortable, 30–40% is manageable but leaves less room for a rate rise at renewal, and above 40% means the rest of your spending is being organised around the mortgage. What matters more than the percentage is what happens when you refix: run the payment again at two or three points higher and see whether the number still works. That, rather than the current rate, is the risk you are actually taking on.
Bear in mind this calculator assumes the standard 1257L tax code with no pension contribution or student loan. Both reduce take-home, and a student loan in particular takes 9% of everything above its threshold, so if either applies to you the honest share is higher than the figure above. Work out your real net pay on the main calculator first, or check the student loan calculator if you are on one of the five plans.
2026/27 income tax rates, checked 28 August 2026 by Hadi. Purchase tax rates checked 2026-09-01 against HMRC, Revenue Scotland and the Welsh Revenue Authority. This is an estimate, not mortgage advice: rates you are offered depend on the lender, your credit file and their affordability assessment. Method on the about page.
How to use the mortgage calculator
- 1
Enter the property price and your deposit, which sets your loan to value.
- 2
Enter the rate and the term, and the monthly payment is calculated on a repayment basis.
- 3
Enter your salary so the payment can be shown against your actual take-home, not your gross.
- 4
Check the purchase tax line for your nation, whether Stamp Duty, LBTT or LTT.
When should you use the mortgage calculator?
Use it when working out affordability, because a lender quotes against your gross salary but you pay from your take-home.
You are working out what you can afford
Lenders quote against gross salary, but you pay the mortgage out of take-home.
Two different deposits
Crossing into a lower loan-to-value band cuts the rate, and 60% is where pricing stops improving.
Buying in Scotland or Wales
LBTT and LTT are not Stamp Duty, and the thresholds differ.
First-time buyer
First-time buyer relief changes the purchase tax, sometimes to nothing.
Where to go next
- Cost of living calculatorTo compare renting in another city instead.Open
- Household income calculatorTo add a second income to the affordability picture.Open
- Reverse tax calculatorTo the gross salary a target take-home needs.Open
- Salary percentile calculatorTo see where your income sits nationally.Open
All 51 calculators share one tested engine, so a figure from the mortgage calculator agrees with every other page here. See the full calculator index or the pay and tax guides.