Mortgage affordability calculator
Roughly what a lender will offer, what that buys with your deposit, and what it costs a month.
- Household income
- £0
- At your chosen multiple
- £0
- Less monthly debts
- £0
- Plus your deposit
- £0
- Price you could reach
- £0
There is no official answer to this
Unlike stamp duty or income tax, affordability has no published rule. Every lender runs its own model over your income, your commitments, your credit file, and how the payment would survive a rate several points higher than the one you are quoted. Two lenders looking at identical paperwork routinely differ by tens of thousands of pounds.
What is standard is the shape: a multiple of household income, reduced by what you already owe each month. That is why the multiple here is a control rather than a fact. Move it and you can see the entire range you might be offered.
What you could borrow at each income
The calculator takes your own figures. This table is the same sum with no other debts, for a single applicant, so you can find your income and read across. A joint application adds the two incomes first.
| Income | 4× | 4.5× | 5× | A month at 4.5× |
|---|---|---|---|---|
| £20,000 | £80,000 | £90,000 | £100,000 | £500 |
| £30,000 | £120,000 | £135,000 | £150,000 | £750 |
| £40,000 | £160,000 | £180,000 | £200,000 | £1,000 |
| £50,000 | £200,000 | £225,000 | £250,000 | £1,251 |
| £60,000 | £240,000 | £270,000 | £300,000 | £1,501 |
| £80,000 | £320,000 | £360,000 | £400,000 | £2,001 |
| £100,000 | £400,000 | £450,000 | £500,000 | £2,501 |
Repayment mortgage at 4.5% over 25 years. The rate is an assumption you can change in the calculator; there is no official one.
What a monthly payment will repay
Many people start from what they can pay each month rather than what they earn. The loan a payment clears depends heavily on the rate, so the table shows two. The last column is the income a lender would want to see at four and a half times.
| A month | Loan at 4.5% | Loan at 6% | Income at 4.5× |
|---|---|---|---|
| £500 | £90,000 | £77,600 | £20,000 |
| £800 | £143,900 | £124,200 | £32,000 |
| £1,000 | £179,900 | £155,200 | £40,000 |
| £1,200 | £215,900 | £186,200 | £48,000 |
| £1,500 | £269,900 | £232,800 | £60,000 |
| £2,000 | £359,800 | £310,400 | £80,000 |
Over 25 years, rounded to the nearest £100. Lenders also test that the payment holds up at a higher rate, so the amount you are offered can be lower.
The deposit does two jobs
The obvious one is reach: every pound of deposit is a pound more property, on top of whatever you borrow. The one people miss is the rate. Lenders price on loan to value, the share of the price you are borrowing, and the steps at 90%, 85% and 75% are worth real money. Crossing one of those lines can be worth more than the extra deposit itself.
What your deposit reaches
Loan to value is the loan as a share of the price. A larger deposit lowers it, which is what moves you into a cheaper rate band. These figures use four and a half times income and no other debts.
| Deposit | On £30,000 | On £45,000 | On £60,000 |
|---|---|---|---|
| £5,000 | £140,000 at 96% | £207,500 at 98% | £275,000 at 98% |
| £10,000 | £145,000 at 93% | £212,500 at 95% | £280,000 at 96% |
| £15,000 | £150,000 at 90% | £217,500 at 93% | £285,000 at 95% |
| £25,000 | £160,000 at 84% | £227,500 at 89% | £295,000 at 92% |
| £50,000 | £185,000 at 73% | £252,500 at 80% | £320,000 at 84% |
Price reached, then loan to value.
Clear the small debts first
A monthly commitment comes off your borrowing at the full multiple, because a lender treats it as income that cannot service a mortgage. At four and a half times, £200 a month of car finance costs you £10,800 of borrowing. Paying off a small balance before you apply is frequently worth more than saving the same sum again, and it is the single most effective thing most applicants can do in the months beforehand.
Buying with a partner
For a joint application a lender adds the two incomes together and applies the multiple to the total, so two people on £30,000 are assessed much like one person on £60,000. The second income box does exactly that. Each person's debts still count in full, and a lender may treat a part-time, self-employed or very new second income more cautiously.
What this leaves out
Stamp duty, legal fees, survey and moving costs all come out of your deposit, not on top of it, so the price you can reach is lower than the figure here unless you have set that money aside separately. Lenders also apply a stress test, checking the payment still works at a materially higher rate, which can bind before the multiple does.
Common questions
- Will a lender definitely lend me this?
- No. There is no official rule for affordability, and no two lenders run the same model. Each one scores your income, your debts, your credit file and how the payment survives a stress rate several points above the one you are offered. This shows the shape of the calculation, with the income multiple as something you can move, so you can see how far a change in deposit or debts pushes the answer.
- What multiple should I use?
- Four and a half times household income is the common ceiling and a reasonable default. Some lenders stretch further for higher earners or particular professions, and some hold at four. Nudge it and watch what happens: the multiple moves the answer far more than anything else on this page.
- Why do my debts cost me so much borrowing?
- Because a lender treats a monthly commitment as income that cannot service a mortgage, so it comes off at the same multiple. A £200 a month car finance at four and a half times is £10,800 less to borrow. Clearing a small loan before applying is often worth more than saving the same amount again.
- Does the deposit count towards what I can borrow?
- It does not increase the loan, it increases the price you can reach, pound for pound. It also moves you into a better rate band: the share of the price you are putting down is what lenders price on, and the steps at 10%, 15% and 25% are worth real money on the rate.
- How much mortgage can I get on my salary?
- At four and a half times income, which is the usual ceiling, £16,000 a year supports about £72,000, £30,000 supports £135,000 and £60,000 supports £270,000. At four times those figures fall by a ninth, and at five times they rise by a ninth. Monthly debts then come off at the same multiple, so these are ceilings rather than offers.
- What mortgage can I get for £800 a month?
- Over 25 years, £800 a month repays about £143,900 at 4.5% and about £124,200 at 6%. A lender usually tests the payment at a higher rate than the one you are quoted, so the loan it offers can be lower than the payment alone suggests. The second table on this page works the same sum for other payments.
- How much mortgage can I get with a £15,000 deposit?
- The deposit does not set the loan, your income does. On £45,000 at four and a half times the loan is £202,500 whether the deposit is £5,000 or £50,000. What £15,000 changes is the price you can reach, £217,500, and your loan to value, 93%, which is what lenders price the rate on.
- Does a second income count?
- Yes. For a joint application a lender adds the two incomes and applies the multiple to the total, which is what the second income box does here. Some lenders treat a part-time, self-employed or very recent second income more cautiously, and each applicant's own debts reduce the joint figure in full.