Debt-to-income ratio calculator

How to calculate your debt-to-income ratio

Add up what you pay every month towards debts, divide it by what you earn in a month before tax, and turn the answer into a percentage. That is the whole sum. The Consumer Financial Protection Bureau puts it in one line: your debt-to-income ratio is all your monthly debt payments divided by your gross monthly income.

Two details trip people up more than anything else in that sum.

The first is that the income figure is before tax, not what lands in your account. People often use their take-home pay, which makes the ratio look far worse than the lender’s version and sends them away thinking they cannot borrow when they can.

The second is that it is the monthly payment that counts, not the balance. A $40,000 student loan on a $210 plan contributes $210. The size of the debt behind the payment does not enter this calculation at all, which is why someone with a large mortgage and nothing else can have a healthier ratio than someone with four small loans.

What counts as debt, and what does not

This is where most people get a wrong answer, because the instinct is to list everything you pay. A lender is not measuring your cost of living. It is measuring the fixed obligations that would still arrive if your life got smaller.

For credit cards, use the minimum on the statement, not what you actually pay. If you clear the card in full every month, the lender still counts the minimum, because that is the obligation. It feels unfair to people who are careful with cards, and it is simply how the calculation is defined.

One trap worth naming: a student loan on a deferment or an income-driven plan of $0 is not always treated as $0. Lenders often substitute a percentage of the balance instead. If that is your situation, ask the loan officer which figure they will use before you build any plans on it.

What is a good debt-to-income ratio?

There is no single pass mark, because different loan products draw the line in different places. These are the figures that actually get used.

In the example above, 36.3% is a third of a percentage point over the comfortable line. That sounds like a technicality, and in human terms it is, but underwriting does not round in your favour. Clearing $20 a month of debt, or earning $667 more a year, moves that person from one side of the line to the other. It is worth knowing when you are that close, because the fix is usually small.

How do you calculate debt to income ratio for a mortgage?

The same way, with one change: you use the payment on the house you want to buy, not the rent you pay now. And the housing payment the lender uses is the full one, not just principal and interest.

That full payment is usually written PITI: principal, interest, taxes and insurance. Add mortgage insurance if your deposit is under 20%, and homeowners' association dues if the property has them. People tend to quote themselves the principal-and-interest figure from a rate advert, then wonder why the lender’s ratio is several points worse than their own.

Use the proposed payment box on this page before you fall in love with a listing. It takes ten seconds and it is the same arithmetic the underwriter will do.

Front-end and back-end: the two ratios lenders use

Lenders usually look at two numbers, and most free calculators only give you one.

• The front-end ratio is your housing payment divided by your gross income. It asks whether the house alone is affordable.
• The back-end ratio is every debt payment, housing included, divided by the same income. It asks whether your whole position is affordable.

You will often see them written together as 28/36: housing no more than 28% of gross income, all debts no more than 36%. It is worth being clear that this is a long-standing lending guideline rather than a published rule, and plenty of approved loans sit outside it. It remains a sound place to aim, which is a different claim from saying it is a limit.

The household in the example has a front-end ratio of 25% and a back-end of 36.3%. Housing is comfortable; it is everything else that pushes them over. That distinction matters, because it tells you to look at the car loan rather than the house.

Is 43% still the limit?

You will read everywhere that 43% is the legal maximum for a qualified mortgage. That stopped being true, and it is the single most out-of-date thing repeated about this subject.

The CFPB’s General QM Final Rule removed the 43% debt-to-income cap and replaced it with a price-based test. A first-lien loan now gets the qualified-mortgage safe harbour if its annual percentage rate is no more than 150 basis points above the average prime offer rate for a comparable loan, with a rebuttable presumption between 150 and 225 basis points. The change became mandatory for applications received on or after 1 October 2022.

So 43% is no longer a legal ceiling. It survives as a habit, as a number many lenders still use internally, and as the point where options start narrowing. Treat it as a useful landmark rather than a wall, and do not let an article written in 2015 convince you that 44% makes you ineligible.

How to bring your ratio down

Only two things move this number: the payments go down, or the income goes up. What matters is choosing the lever that moves it fastest.

1. Clear the debt with the biggest monthly payment, not the biggest balance. This is the opposite of how you would pay off debt to save interest, and it surprises people. In the example above, clearing the $380 car payment takes the ratio from 36.3% to 30.0%. Clearing the $210 student loan only reaches 32.8%, even though you might owe far more on the student loan. The ratio cares about the payment.
2. Do not open anything new. A car financed two months before a mortgage application has sunk more applications than almost anything else. The same goes for furniture on finance for the house you have not bought yet.
3. Get income documented. Bonus, overtime and side work often count, but usually only with a two-year history. If you have it, make sure it is on the paperwork; if you do not, do not count it.
4. Pay down a card to cut its minimum. Because the minimum is a percentage of the balance, paying a card down lowers the payment the lender counts, which helps twice over.
5. Be careful with consolidation. Stretching debts over a longer term lowers the monthly payment and therefore the ratio, which can genuinely help an application. It usually means paying more interest in total. That can be a reasonable trade for a few months, and a poor one as a permanent arrangement.

A word of caution about all of this. These moves make the ratio read better, and the ratio is a proxy for something real. Shuffling payments around so a number clears a threshold, while owing just as much, is how people end up approved for something they cannot carry. The calculator will tell you what a lender will think. Whether the payment fits your life is a question it cannot answer.