Not sure where to start? These are the lessons and games we recommend most to students, parents and teachers on Basic-mathematics.com. Each lesson explains the topic in plain language, walks you through worked examples step by step, and ends with practice so you can check your understanding. Pick one below, or use the menu to find lessons on fractions, algebra, geometry, statistics and more.
Enter your monthly income and debt payments. You'll see both ratios lenders use, how they compare with the limits for conventional, FHA, VA and USDA mortgages, and how much house payment your income can support.
Pick a common limit, or type the one your lender gave you.
Your debt-to-income ratio (DTI) is the share of your gross monthly income that goes to debt payments. Mortgage lenders look at two versions:
Front-end ratio = housing payment ÷ gross monthly income × 100
Back-end ratio = (housing payment + other monthly debts) ÷ gross monthly income × 100
The housing payment is either your rent or, if you own or are buying a home, your full mortgage payment, often called PITI: principal, interest, taxes and insurance, plus mortgage insurance and HOA dues.
Example: you earn $6,000 a month before taxes. Your new mortgage payment would be $1,500 and you pay $350 on a car and $150 on credit cards.
The back-end ratio is the one most lenders care about. A long-standing rule of thumb is 28/36: no more than 28% of income for housing and 36% for all debts.
These are the usual starting points. Lenders can be stricter, and programs update their rules from time to time. Try them with the buttons in the calculator, or type your lender’s own limit.
| Loan type | Housing | Total | When it can go higher |
|---|---|---|---|
| Conventional | No set limit | 36% | Up to 45% with good credit and savings; up to 50% with Fannie Mae's automated approval |
| FHA | 31% | 43% | Higher with compensating factors such as savings or a strong credit history; automated approvals can go into the 50s |
| VA | No set limit | 41% | Above 41% if your residual income (money left after bills) is at least 20% above VA's guideline |
| USDA | 29% | 41% | Up to 32% / 44% with a 680+ credit score and a compensating factor |
Each lender can set stricter rules. Before 2021, many loans also had a 43% cap under the federal "qualified mortgage" rule; that cap has since been replaced by a test based on the loan's price.
Gross pay: your income before taxes and other deductions. Because take-home pay is smaller, the same debts take a bigger share of it, so keep some room below the limits.
36% or less is generally seen as healthy and qualifies for most loans. 37% to 43% is workable for many mortgages. Above 43%, fewer loans are available and they usually need compensating factors such as savings or a high credit score. Above 50%, most mortgages are out of reach.
No. When you buy a home, lenders replace your current rent with the payment on the new mortgage. To check whether you would qualify, enter the new payment as your housing payment.
No. Your income isn't on your credit report, so your DTI isn't part of your credit score. But the balances behind your debts can affect your score through how much of your credit you use.
Not always. Lenders verify income with pay stubs and tax returns, and take debts from your credit report. For example, they may count a student loan in deferment using a set percentage of the balance. Use this calculator for planning, then confirm with a lender.
Sources: CFPB: What is a debt-to-income ratio? · Fannie Mae Selling Guide B3-6-02 · Chase: DTI for FHA loans · Veterans United: VA DTI guidelines · USDA Handbook HB-1-3555, Chapter 11 · USDA notice of September 16, 2025 (PITI ratio) · CFPB: General QM rule. This calculator gives estimates for planning, not financial advice.