Affordability Ratio Calculator
Compute your affordability ratio (front-end ratio): monthly housing costs as a percentage of gross monthly income. The tool interprets the result against the 28% homebuyer and 30% renter benchmarks, and shows the maximum housing cost you can afford at each threshold. To see what those monthly costs would look like as a loan, try the mortgage payment calculator.
Guideline only. Lenders weigh the back-end debt-to-income ratio, credit, and down payment alongside this ratio.
Quick Answer
With $1,650 of monthly housing costs on $6,666.67 of gross income ($80,000 a year), your affordability ratio is 24.75%: comfortably inside the 28% homebuyer guideline. At that income the tool shows a maximum of $1,866.67/month at 28% and $2,000.00/month at 30%.
Worked example, checked against this exact tool
Monthly housing costs of $1,650 on gross monthly income of $6,666.67 ($80,000/year): affordability ratio = $1,650 ÷ $6,666.67 × 100 = 24.75%, comfortably within the 28% buyer guideline. Maximum affordable housing: $1,866.67/month at 28% and $2,000.00/month at 30%.
What the ratio means
The affordability ratio (also called the front-end ratio or housing ratio) is the share of gross income consumed by housing. Include all housing costs: rent or mortgage principal and interest, property taxes, homeowners or renters insurance, PMI, and HOA fees. A $1,200 mortgage payment with $300 taxes, $100 insurance, and $50 PMI is $1,650 of housing cost, not $1,200.
The 28% and 30% benchmarks
Conventional mortgage lenders prefer a front-end ratio of 28% or less: the classic 28/36 rule pairs it with a 36% ceiling on all debts combined. HUD draws the affordability line for renters at 30%: above that you are “cost-burdened,” and above 50% “severely cost-burdened”. Between 28% and 30% is a gray zone: fine for a renter, stretching for a buyer. If you are deciding whether to keep renting or buy, run the numbers through a rent or buy comparison too.
How it pairs with the back-end ratio
Housing is only half the affordability picture: lenders also cap your total debts (housing plus car, cards, student loans) at roughly 36% of income, with many conventional programs stretching to 43-45%. Check that side with the back-end ratio calculator before house hunting, because a fine-looking 25% front-end ratio can still be unaffordable once other debts are counted.
What competing calculators miss
Most housing tools compute a maximum loan or skip interpretation entirely. The previous version of this page had the right two inputs but its calculator was truncated mid-formula and could never run. This rewrite computes the ratio, interprets it against both the buyer and renter benchmarks, and converts the result into the maximum housing cost at each threshold.
Frequently asked questions
What is the affordability ratio?+−
Monthly housing costs divided by gross monthly income, times 100. It is also called the front-end ratio.
What is a good affordability ratio?+−
28% or less for buyers; 30% or less for renters. These are the standard conventional and HUD benchmarks.
What does cost-burdened mean?+−
Spending over 30% of income on housing (HUD definition); over 50% is severely cost-burdened.
What counts as housing costs?+−
Rent or P&I, property taxes, insurance, PMI, and HOA fees: the full monthly burden, not just the mortgage.
How do I compute gross monthly income?+−
Annual salary ÷ 12; hourly wage × hours/week × 52 ÷ 12.
What is the front-end ratio?+−
Another name for the affordability ratio: housing costs vs income, before other debts.
What is the 28/36 rule?+−
Lenders’ guideline: housing at 28% of income or less (front-end), all debts at 36% or less (back-end).
Can I afford a ratio above 30%?+−
Sometimes, with strong credit, low other debts, or high income, but it leaves less buffer for everything else.
Does this work for renters?+−
Yes: use monthly rent plus renters insurance and any mandatory fees as the housing cost, judged against 30%.
Why gross income, not take-home?+−
Lenders and HUD standardize on gross income so the benchmarks are comparable; using net income would understate the ratio.
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References
- Bankrate: What Is the 28/36 Rule for Home Affordability? – Bankrate (accessed 2026-10-17)
- Hometap: Ideal Mortgage Income Percentage – Hometap (accessed 2026-10-17)
- Nasdaq: The 28/36 Rule: How It Affects Your Mortgage Approval – Nasdaq (accessed 2026-10-17)
- MasterClass: The 28/36 Rule Explained: How to Budget Using the 28/36 Rule – MasterClass (accessed 2026-10-17)
- Opendoor: How to Calculate Your Mortgage Affordability: Rules, Ratios, and 2026 Limits – Opendoor (accessed 2026-10-17)
- New American Funding: The 28/36 Mortgage Rule Explained – New American Funding (accessed 2026-10-17)
- Federal Reserve: Assessing the Severity of Rent Burden on Low-Income Families – Board of Governors of the Federal Reserve System (accessed 2026-10-17)
- Bipartisan Policy Center: What Is Affordable Housing? – Bipartisan Policy Center (accessed 2026-10-17)
- Philadelphia Fed: Rental Housing Affordability Data Explorer - Definitions – Federal Reserve Bank of Philadelphia (accessed 2026-10-17)
- PocketLaw: 24 CFR - Cost Burden Definition – PocketLaw (24 CFR 91.5) (accessed 2026-10-17)