Plot No. 29 · Money & Finance
Mortgage Affordability Calculator
Estimate how much you could borrow for a mortgage using the income multiple method UK lenders apply. Add your annual income and any partner income, choose a multiple (most lenders cap around 4.5 times income), and the tool multiplies the two to get a maximum loan. Adding your deposit gives the top property price you could reach.
This is an income-multiple estimate, not a lending decision. To see the monthly cost of a mortgage at a given rate and term, use the mortgage repayment calculator.
The link saves your inputs so you can bookmark or share this exact result.
How mortgage affordability is estimated
This calculator uses the income multiple method UK lenders apply to estimate the maximum you could borrow. It adds your annual income to any partner income, multiplies the total by your chosen multiple (most lenders cap around 4.5 times income, some reach 5 for strong applicants), and that gives a maximum loan. Adding your deposit gives the top property price you could reach, because price equals loan plus deposit.
It is deliberately an estimate of the lender's offer ceiling, not the monthly cost. A bigger deposit does not raise the income-multiple loan cap, but it lifts the total price you can reach and lowers your loan-to-value ratio, which usually unlocks better rates. To check what a given price actually costs each month, use the separate mortgage repayment calculator.
How to use the mortgage affordability calculator
- Enter your annual income, and a partner's income too if you are buying together (leave it at zero if not).
- Pick an income multiple: 4 is cautious, 4.5 is the typical cap, 5 is stretched.
- Add your deposit, then read the maximum loan and property price, and cross-check the monthly cost on the repayment calculator.
Worked examples
Single buyer, typical cap
Inputs: Income 35,000, no partner income, 4.5 times multiple, 25,000 deposit
Result: Maximum loan 157,500 plus the deposit gives a property price of 182,500, with the deposit at 13.7% of that price.
Buying as a couple
Inputs: Income 35,000, partner 30,000, 4.5 times, 25,000 deposit
Result: Combined income 65,000 at 4.5 times borrows 292,500, supporting a 317,500 property with the deposit at 7.9%.
Limitations and common mistakes
Edge cases and limitations
- Income multiples are a rule of thumb. Real affordability checks also weigh your outgoings, credit history and other commitments.
- It does not estimate the monthly payment or stress-test the rate, so a loan you could be offered is not always one you can comfortably afford.
- Lender caps vary and change, and some borrowers (such as first-time buyers on certain schemes) face different limits.
Common mistakes
- Treating the maximum as a target. Borrowing to the ceiling leaves no slack if rates rise at remortgage.
- Assuming a larger deposit raises the loan cap, when it only raises the total price you can reach.
Frequently asked questions
How much can I borrow for a mortgage?
Most UK lenders cap a mortgage at around 4 to 4.5 times your annual income, with some stretching to 5 times for strong applicants. On a £35,000 income at 4.5 times you could borrow about £157,500. Add a £25,000 deposit and that supports a property price of around £182,500.
Is this the same as a repayment calculator?
No. This tool estimates the maximum a lender might offer based on income multiples. It does not work out your monthly payment. Once you know a price, use the mortgage repayment calculator to see the actual monthly cost at a given rate and term, which is the figure that decides what is truly affordable.
Does a bigger deposit let me borrow more?
A bigger deposit does not raise the income-multiple loan cap, but it does lift the total property price you can reach because price equals loan plus deposit. It also lowers your loan-to-value ratio, which usually unlocks better interest rates and can improve your chances of approval.
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