Home Affordability Calculator
Free Home affordability Calculator for loans & mortgages. Enter your numbers to see returns, costs, and optimized scenarios instantly.
Formula
Max Housing = Gross Monthly Income × 28%; Max Total Debt = Gross Monthly Income × 36%
The 28/36 rule states that housing costs (mortgage, taxes, insurance) should not exceed 28% of gross monthly income (front-end DTI), and total debt payments should not exceed 36% of gross monthly income (back-end DTI). The calculator uses the more restrictive of these two limits to determine the maximum affordable home price.
Worked Examples
Example 1: First-Time Homebuyer Affordability
Problem: A couple earns $95,000 combined annually, has $600/month in car and student loan payments, saved $40,000 for a down payment. Current rates are 6.5% for a 30-year mortgage. Property tax rate is 1.1% and insurance is $1,400/year. How much house can they afford?
Solution: Step 1: Calculate monthly income\n $95,000 / 12 = $7,916.67/month\n\nStep 2: Apply 28/36 rule\n Front-end (28%): $7,916.67 × 0.28 = $2,216.67 max housing\n Back-end (36%): $7,916.67 × 0.36 = $2,850 max total debt\n Max housing from back-end: $2,850 - $600 = $2,250\n Limiting factor: Front-end at $2,216.67\n\nStep 3: Subtract taxes and insurance (estimated)\n For a ~$330,000 home:\n Monthly tax: $330,000 × 0.011 / 12 = $302.50\n Monthly insurance: $1,400 / 12 = $116.67\n Max mortgage payment: $2,216.67 - $302.50 - $116.67 = $1,797.50\n\nStep 4: Calculate max loan from max payment\n Max loan ≈ $284,000\n Max home price = $284,000 + $40,000 = $324,000
Result: Max home price: ~$324,000 | Monthly payment: ~$2,217 | Front-end DTI: 28%
Example 2: High-Income Buyer with Significant Debt
Problem: A buyer earns $150,000/year, has $2,000/month in existing debts, has $100,000 saved. Rate is 6.0%, 30-year term, 1.3% tax rate, $2,000/year insurance. What can they afford?
Solution: Step 1: Monthly income = $150,000 / 12 = $12,500\n\nStep 2: DTI limits\n Front-end (28%): $12,500 × 0.28 = $3,500\n Back-end (36%): $12,500 × 0.36 = $4,500\n Max housing from back-end: $4,500 - $2,000 = $2,500\n Limiting factor: Back-end at $2,500\n\nStep 3: The high debt load is the constraint\n For ~$450,000 home:\n Monthly tax: $450,000 × 0.013 / 12 = $487.50\n Monthly insurance: $2,000 / 12 = $166.67\n Max mortgage payment: $2,500 - $487.50 - $166.67 = $1,845.83\n\nStep 4: Max loan ≈ $308,000\n Max home price = $308,000 + $100,000 = $408,000
Result: Max home price: ~$408,000 | Debt limits buying power despite high income
Frequently Asked Questions
What is the 28/36 rule for home buying?
The 28/36 rule is a widely used guideline in mortgage lending that helps determine affordable housing costs. The first number, 28, means your total housing expenses (mortgage payment, property taxes, homeowner's insurance, and HOA fees) should not exceed 28% of your gross monthly income. The second number, 36, means your total monthly debt obligations (housing costs plus all other recurring debts like car payments, student loans, and credit card minimums) should not exceed 36% of your gross monthly income. For example, if you earn $7,000 per month gross, your housing costs should stay below $1,960 (28%) and total debts below $2,520 (36%). While many lenders now allow higher ratios up to 43-50% for qualified borrowers, staying within the 28/36 guideline provides a comfortable financial cushion.
How does my down payment affect home affordability?
Your down payment directly impacts affordability in several ways. A larger down payment reduces the loan amount, lowering your monthly mortgage payment and total interest paid over the life of the loan. Putting down 20% or more eliminates the need for Private Mortgage Insurance (PMI), which typically costs 0.3%-1.5% of the loan amount annually, saving hundreds per month. For example, on a $300,000 home, a 20% down payment ($60,000) avoids approximately $100-$300 per month in PMI. A larger down payment also gives you a lower loan-to-value (LTV) ratio, which can qualify you for better interest rates. However, depleting all your savings for a down payment is risky — financial advisors recommend keeping 3-6 months of expenses in reserve after closing. Consider FHA loans requiring only 3.5% down if saving 20% would take years.
How does interest rate affect how much home I can afford?
Interest rates have a dramatic impact on home affordability. Even a 1% rate change can shift your buying power by tens of thousands of dollars. For example, at a 5% rate with a $2,000 monthly budget for mortgage payments on a 30-year loan, you could afford approximately a $373,000 mortgage. At 6%, that same payment only supports a $333,000 mortgage — a $40,000 reduction in buying power. At 7%, it drops further to $300,000. Over the life of a 30-year loan, a 1% higher rate on a $300,000 mortgage costs approximately $60,000 more in total interest. This is why rate shopping is crucial — getting quotes from at least 3-5 lenders can save you 0.25%-0.5% on your rate. Consider buying discount points (each point costs 1% of the loan and typically reduces the rate by 0.25%) if you plan to stay in the home long-term.
How accurate are the results from Home Affordability Calculator?
All calculations use established mathematical formulas and are performed with high-precision arithmetic. Results are accurate to the precision shown. For critical decisions in finance, medicine, or engineering, always verify results with a qualified professional.
How do I get the most accurate result?
Enter values as precisely as possible using the correct units for each field. Check that you have selected the right unit (e.g. kilograms vs pounds, meters vs feet) before calculating. Rounding inputs early can reduce output precision.
What formula does Home Affordability Calculator use?
The formula used is described in the Formula section on this page. It is based on widely accepted standards in the relevant field. If you need a specific reference or citation, the References section provides links to authoritative sources.