The 28/36 Rule Explained: How Lenders Size Your Mortgage (2026)

The two ratios

Both ratios compare a monthly obligation to your gross monthly income, meaning income before tax.

Front end (28 percent): the full housing payment only, principal, interest, property tax, homeowners insurance, PMI, and HOA dues.
Back end (36 percent): that housing payment plus every other recurring debt, car loans, student loans, credit card minimums, and other loans.

The lower of the two limits is your ceiling. A lot of other debt pushes the back end ratio down and shrinks the housing budget the front end would otherwise allow.

A worked example

Worked example: $7,500 gross monthly income

28 percent front end cap (housing)$2,100
36 percent back end cap (all debt)$2,700
Existing car + student loan payments$600
Housing room left under the back end cap$2,100
Binding limit$2,100

With 600 dollars of other debt, the back end cap also lands at 2,100 dollars, so both ratios agree. Add more debt and the back end becomes the limit that holds you back.

How to improve your ratios

You can move these numbers before you apply:

Pay down revolving debt. Clearing a car loan or credit card frees back end room dollar for dollar.
Raise documented income. A raise, a second job, or countable side income lifts both caps.
Increase the down payment. A smaller loan means a smaller payment for the same house, and 20 percent down removes PMI from the front end ratio.
Buy less house. The simplest lever, and the one that leaves the most breathing room in your real budget.

Remember the rule is a maximum, not a target. Borrowing right up to 28 and 36 leaves little margin for the rest of your life.

Frequently asked questions

What does 28/36 actually stand for?

The two percentages of gross monthly income the rule caps: 28 percent for housing costs (the front end ratio) and 36 percent for total debt including housing (the back end ratio). Staying under both is what lenders look for.

Is the 28/36 rule a hard requirement?

No, it is a guideline. Many loan programs approve borrowers above these ratios, sometimes into the mid 40s on the back end, with compensating factors like a high credit score, a big down payment, or cash reserves. But the rule reflects what is comfortable, not just what is allowed.

Does it use gross or net income?

Gross income, before taxes and deductions. Since your take home pay is lower, a payment that fits the 28 percent gross cap can still feel tight in your actual monthly budget, which is why aiming below it is wise.

What debts count in the back end ratio?

Recurring monthly debt payments: the new housing payment, car loans, student loans, minimum credit card payments, personal loans, and court ordered payments like child support. Everyday spending such as groceries and utilities is not counted.