Debt to Income Ratio Calculator United Kingdom

What the debt to income ratio calculator does

The calculator shows what share of your income is already committed to debt before you spend anything else. Enter your gross salary, your take-home pay and the monthly cost of your mortgage or rent, loans and cards. It returns two ratios, the income left once the debts are paid, and the monthly headroom you have before a lender would see you as stretched.

Underwriters look at this early. Two people on the same salary can get very different answers on a mortgage application because one is paying off car finance and a couple of card balances. The ratio shows that difference in one figure, before you apply and leave a search on your credit file.

How the ratio is worked out

Add every fixed monthly debt payment, divide by monthly income and multiply by a hundred. The calculator divides your annual salary by twelve for the gross ratio and also measures the same commitments against your take-home pay for the net ratio.

The gross ratio is the one lenders quote, because almost every affordability model in the market starts from gross income. The net ratio is usually five to fifteen percentage points higher, and it describes how the month actually feels. The gap between them is the tax and National Insurance you pay before the debts are settled.

For example, someone earning £45,000 (£3,750 a month gross, £2,900 take-home) who pays £900 in rent, £250 on loans and £80 on cards has £1,230 of commitments: a gross ratio of 32.8% and a net ratio of 42.4%. Against a 45% screen, that leaves about £457 a month of headroom.

Which commitments belong in the total

Fixed, contractual repayments count: the mortgage or rent, personal loans, car finance or a personal contract purchase, credit and store cards, buy now pay later plans with a set schedule, an agreed overdraft reduction, and any maintenance or family loan you are formally repaying.

Running costs do not count. Energy, water, council tax, broadband, insurance, childcare, food and fuel are living expenses that a lender assesses separately, and including them would make the ratio meaningless for comparison. For cards, if you regularly pay more than the minimum, use the amount you actually pay, because that is the commitment you live with.

Reading the result against our comfort screen

The calculator compares your gross ratio with a comfort screen of 45 per cent and shows the difference as monthly headroom. That screen is our own editorial benchmark, set where most lenders start asking harder questions. No lender publishes it, and no UK regulator sets a debt to income limit. The FCA’s rule in MCOB 11.6 requires a lender to assess affordability and to stress the interest rate by at least one percentage point; it names no ratio. Healthy headroom means you can take on a further commitment without the ratio becoming a problem. Zero headroom means your existing debts have already used the room a lender would allow for new borrowing.

Headroom is often more useful than the ratio because it is in pounds a month. A few hundred pounds of headroom tells you straight away whether a car finance quote is realistic, and in reverse, how much of a monthly payment you would need to clear before an application looks comfortable.

The one limit a UK authority does set

The Bank of England’s Financial Policy Committee limits loan to income, which is different from debt to income. Debt to income compares what your borrowing costs each month with your income; loan to income compares the size of the mortgage with your income. The FPC caps mortgages at or above 4.5 times income at 15 per cent of new mortgage lending. Since its July 2025 Recommendation, that cap applies across the market as a whole rather than to each lender, and individual lenders can currently exceed 15 per cent under a PRA modification by consent. Lenders extending less than £150 million of regulated mortgages a year, or fewer than 300 of them, are outside the limit.

Borrowing at more than 4.5 times income is therefore allowed, but it competes for a capped share of the market, which is why lenders ration it.

The indicative borrowing figure

The calculator also multiplies your gross annual income by 4.5 to show the loan size at which you reach that high loan to income level. Treat it as a rough guide rather than a decision in principle. It ignores your existing debts, your deposit and the stressed rate the lender will apply, all of which usually bring the real figure down.

Compare it with your headroom. A large indicative figure with almost no headroom is the typical profile of someone whose salary would support a good mortgage but whose current commitments stand in the way. That can be fixed, and the ratio tells you roughly how much debt has to go.

Bringing the number down

You can lower the payments or raise the income. Cutting payments is usually faster and fully in your control.

Clearing the smallest balances first removes whole payments, which moves the ratio more than spreading the same money across several accounts. Consolidating expensive card debt into one lower-rate payment reduces the monthly figure even though you owe the same amount. Extending a loan term has the same effect on the ratio but costs more interest overall. Avoid opening new credit in the six months before a mortgage application, since a new agreement adds a payment at exactly the wrong time.

On the income side, a pay rise, a second income on a joint application, or overtime and bonuses you can evidence all raise the denominator. Lenders differ in how much variable pay they count, so be cautious with anything irregular.

Using the calculator well

Run it twice: once with your position today, and once with the commitment you are considering added. The second run shows the ratio a lender would see after the new borrowing. If it crosses the comfort screen, you know before anyone runs a credit search.

Revisit it every few months while you are paying debt down. The ratio falls in visible steps as agreements end, and it tracks the pressure on your monthly budget better than the total balance does.

All figures are an estimate based on what you enter and on the affordability conventions lenders commonly use. Individual lenders use their own models, and this is not financial advice.

About This Tool: Debt to Income Ratio

Debt to income ratio: use this tool to get an instant, accurate estimate. The figures follow official guidance and every rate and threshold is kept up to date for 2026. Adjust the inputs above to match your situation, or browse all our calculators to plan your next step.