A free home affordability calculator with no sign up runs entirely in your browser: enter your gross income, your recurring monthly debts, your down payment, the loan term, and the expected interest rate, and it returns the maximum home price you can reasonably carry under the 28/36 debt-to-income rule. The 28/36 rule caps housing costs at 28% of your gross monthly income and total recurring debt at 36%, and the calculator takes the smaller of those two ceilings, converts that monthly payment into a maximum loan using inverse loan amortization, then adds your down payment to surface a single affordable home price. Because the math executes locally, nothing you type is uploaded, saved, or shared, and there is no account, email, or registration step to unlock the result. This makes the tool well suited for quick sanity checks before you tour a listing, side-by-side comparisons of 15- versus 30-year terms, and rough scenarios as your income or debts shift over the next few months. You can open the Home Affordability Calculator, type a few numbers, and read the answer without leaving the page.
What a No-Sign-Up Affordability Calculator Actually Does
An affordability calculator works in the opposite direction of the loan tools most buyers are used to. A standard mortgage estimator starts with a home price or loan amount and walks forward to a monthly payment. An affordability tool instead starts with the buyer's real-world constraints: how much they earn, what they already owe each month, what they have saved for a down payment, what rate they expect, and how long they want the loan to run. The tool then solves the reverse problem to find the largest loan that payment can support, and the largest home price that loan plus the down payment can cover. The result is a single, conservative benchmark that anchors your house hunt to the numbers you can actually carry, rather than the maximum a lender might theoretically approve.
Because no sign-up step is involved and no server round-trip is required, every input you change recalculates immediately. That makes it practical to run many scenarios in a single sitting: a 30-year term versus a 15-year term, an extra $20,000 down, a 1% lower rate, or the effect of paying off a car loan before you apply.
The 28/36 Rule in Plain English
The 28/36 rule is a debt-to-income guideline used by most lenders as a quick screen for mortgage approval. The "28" is the front-end ratio: housing costs (in this calculator, principal and interest only) should stay at or below 28% of gross monthly income. The "36" is the back-end ratio: the sum of the future mortgage payment plus every other recurring debt you already owe, including car loans, student loans, and minimum credit-card payments, should stay at or below 36% of gross monthly income. Your maximum housing budget is the smaller of the two ceilings — specifically, min(0.28 × income, 0.36 × income − monthly debts). When your other debts are small, the front-end ceiling usually binds; when they are heavy, the back-end ceiling pulls the number down, and in extreme cases the budget can drop to zero. The rule is widely cited by industry sources, including the Consumer Financial Protection Bureau's explainer on debt-to-income ratios.
Run the Calculator in Three Steps
- Enter your gross income and your existing monthly debts. Type your gross monthly or annual income, then add up your recurring monthly obligations outside of housing: the minimum payment on every credit card, the current payment on each car loan, the minimum due on every student loan. These debts are what make the back-end 36% ceiling bite harder than the front-end 28% ceiling.
- Enter your down payment, expected interest rate, and loan term. The down payment is cash you will put toward the purchase, not the loan itself. The interest rate is what you expect to be quoted; a small change in rate shifts the result more than most buyers expect. The loan term is usually 30 years for a balanced budget, with 15 years available if you want to compare a faster payoff.
- Read the affordable home price, loan amount, and maximum monthly housing payment. The three numbers refresh instantly. The maximum monthly housing payment is the smaller of the two DTI ceilings. The loan amount is the inverse-amortized principal that payment supports at the rate and term you entered. The affordable home price is that loan plus your down payment. Treat the home price as the ceiling of your realistic search range, then layer in taxes, insurance, HOA dues, and any PMI to see your true monthly cost.
How Each Input Moves Your Maximum Home Price
To make the relationship between inputs and output concrete, walk through a single example. Take a household with $80,000 of annual gross income, $500 of other monthly debt, $40,000 of cash for a down payment, an expected 6.5% interest rate, and a 30-year term. Gross monthly income is $80,000 ÷ 12 = $6,666.67. The 28% ceiling is 0.28 × $6,666.67 = $1,866.67, and the 36% back-end ceiling is 0.36 × $6,666.67 − $500 = $1,900.00. The smaller number is the front-end $1,866.67, so that becomes the maximum monthly housing payment.
That payment is then run through the inverse-amortization formula: with r = 6.5% ÷ 12 ≈ 0.005417 and n = 30 × 12 = 360 months, the multiplier is ((1 + r)n − 1) ÷ (r × (1 + r)n) ≈ 158.2. Multiplying the ceiling by the multiplier gives a maximum loan of roughly $1,866.67 × 158.2 ≈ $295,300. Adding the $40,000 down payment on top of that yields an affordable home price of about $335,300. Run the same inputs through the tool to see the exact decimals for your scenario. Higher income, lower existing debts, a lower rate, or a longer term all raise the ceiling; the opposite moves push it down.
Why This Is Different From a Mortgage Calculator
An affordability tool and a mortgage calculator are complementary, not interchangeable. A mortgage calculator answers "what will my monthly payment be on a $400,000 loan?" An affordability calculator answers "given what I earn and owe today, how much house can I actually carry?" That distinction matters at the very start of a home search, before you have a listing in mind, because chasing a payment on a specific listing without checking it against your DTI ceiling is how buyers end up approved for more than they can comfortably afford. Many buyers pair the two: a Mortgage Calculator for a specific listing and an affordability tool for the ceiling that defines their realistic search range.
| Tool | Direction | Starting Inputs | Typical Output |
|---|---|---|---|
| Home Affordability Calculator | Reverse | Income, debts, down payment | Maximum home price and loan |
| Mortgage Calculator | Forward | Loan amount, rate, term | Monthly principal and interest |
What the Estimate Leaves Out
The number you see is a clean, principal-and-interest estimate. Real ownership carries several costs that are deliberately excluded so the benchmark stays comparable across buyers and locations. Property taxes, homeowners insurance, HOA or condo fees, and private mortgage insurance (PMI, typically required when the down payment is below 20% of the home price) all add to the monthly outflow. Each one lowers the home price you can comfortably afford. The relationship is straightforward: more carrying cost per month means a smaller loan that the same income can support. Treat the principal-and-interest figure as the maximum ceiling before these extras, and use it together with a quick check of local tax rates and insurance quotes for the neighborhoods you are considering.
| Monthly Cost | Included in the Estimate |
|---|---|
| Principal and interest | Yes |
| Property taxes | No |
| Homeowners insurance | No |
| HOA or condo fees | No |
| Private mortgage insurance (PMI) | No |
Limits to Keep in Mind Before You Make an Offer
The 28/36 rule is a widely used lender guideline, not a guarantee of approval. Real underwriting also weighs your credit score, cash reserves after closing, length of employment, and the specific loan program (FHA, VA, and conventional loans each apply their own limits, and some lenders stretch ratios higher for strong files). The estimate is also a snapshot: a pay raise, a new car loan, or a paid-off student loan can move the ceiling materially. If you want a closer look at where the 28/36 rule can mislead, the Home Affordability Calculator: How Accurate Is It Really? walkthrough is a useful next read. Use this calculator as the starting benchmark for your search and for budgeting conversations, then confirm the actual loan limits, rates, and full monthly cost with a licensed mortgage professional before you make an offer. Estimates are for general information only and are not financial advice.