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28/36 Rule Calculator

Calculate your front-end and back-end DTI ratios using the 28/36 rule to determine your home loan qualification limit.

Income and debt details

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$
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Max qualified housing payment

$26,000.00

Based on the 28/36 rule

Qualification status

Passes both front-end (28%) and back-end (36%) limits.

Front-end DTI

25.0%

Limit: 28%

Back-end DTI

35.0%

Limit: 36%

Income allocation

  • Housing$25,000.0025.0%
  • Other debt$10,000.0010.0%
  • Remaining$65,000.0065.0%

Rule limits

Max housing cost (28% rule)$28,000.00
Max total debt (36% rule)$36,000.00

How the 28/36 rule is applied

Front-end and back-end debt-to-income ratios from your gross income and monthly obligations.

  1. Monthly gross income

    Monthly income=Income\text{Monthly income} = \text{Income}

    Your monthly gross income is $100,000.00.

  2. Front-end DTI ratio

    Front-end DTI=(Housing costMonthly income)×100\text{Front-end DTI} = \left( \frac{\text{Housing cost}}{\text{Monthly income}} \right) \times 100

    $25,000.00 divided by $100,000.00 equals 25.0%. The 28% limit is $28,000.00.

  3. Back-end DTI ratio

    Back-end DTI=(Housing cost+Other debtsMonthly income)×100\text{Back-end DTI} = \left( \frac{\text{Housing cost} + \text{Other debts}}{\text{Monthly income}} \right) \times 100

    Total debt of $35,000.00 divided by $100,000.00 equals 35.0%. The 36% limit is $36,000.00.

  4. Max affordable housing payment

    Budget=min⁡(0.28×Monthly income,(0.36×Monthly income)−Other debts)\text{Budget} = \min(0.28 \times \text{Monthly income}, (0.36 \times \text{Monthly income}) - \text{Other debts})

    The tighter limit gives a qualified housing budget of $26,000.00.

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What is the 28/36 rule?

The 28/36 rule is a classic affordability guideline used by lenders and financial planners. It says housing costs should stay at or below 28% of gross monthly income, and total monthly debt (housing plus everything else) should stay at or below 36%. This calculator applies those ratios to your income and debt payments. All math runs in your browser.

Enter your gross income, monthly housing payment (principal, interest, taxes, insurance, and HOA if applicable), and other recurring debt payments such as car loans or credit card minimums. The tool shows front-end and back-end debt-to-income (DTI) ratios, the maximum housing payment allowed under each limit, and the tighter qualified budget. For a broader monthly take-home split across needs, wants, and savings, the 50-30-20 rule budget calculator applies a different framework. Renters can use the 3x rent calculator for a similar gross-income check on monthly rent. Once you know that payment ceiling, the EMI calculator can translate a loan amount and rate into a monthly installment.

Front-end DTI (28% rule)

Front-end DTI=(Housing costGross monthly income)×100\text{Front-end DTI} = \left( \frac{\text{Housing cost}}{\text{Gross monthly income}} \right) \times 100

Housing cost includes your full monthly housing payment: principal, interest, property taxes, homeowners insurance, and HOA fees when they apply. If gross monthly income is $100,000, the 28% cap allows up to $28,000 per month for housing alone.

Back-end DTI (36% rule)

Back-end DTI=(Housing cost+Other monthly debtsGross monthly income)×100\text{Back-end DTI} = \left( \frac{\text{Housing cost} + \text{Other monthly debts}}{\text{Gross monthly income}} \right) \times 100

Other monthly debts include car loans, student loans, personal loans, and minimum credit card payments. With $100,000 gross monthly income, total debt payments should stay at or below $36,000. If other debts already use $10,000, only $26,000 remains for housing even though the standalone 28% cap is $28,000.

Qualified housing budget

Budget=min⁡(0.28×Income,(0.36×Income)−Other debts)\text{Budget} = \min(0.28 \times \text{Income}, (0.36 \times \text{Income}) - \text{Other debts})

The qualified housing payment is whichever limit binds first. High non-housing debt shrinks the back-end room and can cap housing below the 28% line. Many loan programs allow higher DTI ratios than 28/36, but this rule remains a conservative planning benchmark. For an adjustable-rate home loan with a long initial fixed period, the 10/1 ARM mortgage calculator models how payments can change after the fixed years end.

Frequently asked questions

What counts as housing cost?
Include the full monthly housing payment: principal, interest, property taxes, homeowners insurance, and HOA fees when they apply. Rent counts if you are measuring renter affordability instead of an owned home.
What debts belong in the back-end ratio?
Add recurring monthly obligations such as car loans, student loans, personal loans, and minimum credit card payments. Do not include utilities, groceries, or other living expenses that are not debt payments.
Should I use gross or net income?
The 28/36 rule uses gross income (before tax and most payroll deductions). Lenders typically underwrite on gross income, so this calculator follows the same basis.
Do all lenders require exactly 28% and 36%?
No. The 28/36 rule is a conservative guideline. Many programs allow higher DTI ratios when other strengths compensate, but staying within 28/36 leaves more room in your budget.
How is the max qualified housing payment found?
Take 28% of gross monthly income for the housing-only cap. Take 36% of income minus other monthly debts for the total-debt cap. The qualified budget is the lower of the two, floored at zero.
Can I share my scenario?
Yes. Changing the fields updates the page URL so you can copy and share the same income and debt inputs.

Resources and references

The formulas and methods in this calculator were checked against these independent sources.