Mortgage Affordability Calculator

How to use

1. 1Enter your gross annual income (before tax) and any other monthly debt payments you carry, plus the cash you can put down.
2. 2Enter the mortgage rate you expect and the loan term in years (30 is the most common in the US, 25 in Canada and the UK).
3. 3Click Show to reveal the advanced controls if you want to adjust property tax rate, home insurance rate, PMI rate, HOA dues, or the front-end and back-end DTI caps.
4. 4Read the maximum home price, the maximum loan amount, the monthly PITI breakdown, and which cap (front-end or back-end DTI) is binding.
5. 5Scroll to the rate stress test to see how the max home price moves if rates change before you lock. Use Copy summary to paste the full breakdown into a planning doc or a message to your lender.

About this tool

Mortgage Affordability Calculator answers the question every home buyer searches first: 'how much house can I afford?' Unlike a standard mortgage calculator that goes home price to payment, this tool goes income to maximum home price using the classic lender debt-to-income (DTI) rule known as 28/36. Enter your gross annual income, the total of any other monthly debts you carry (car loan, student loan, minimum credit card payment, child support), the cash you can put down, the mortgage rate, and the loan term. The calculator solves for the highest home price whose total monthly housing cost (principal and interest plus property tax, home insurance, private mortgage insurance, and HOA dues) fits inside two simultaneous caps: a front-end cap (housing as a share of income, conservative default 28%) and a back-end cap (housing plus all other debts as a share of income, conservative default 36%). Both caps are user-editable, so you can dial in FHA-style 31/43, jumbo-conservative 25/33, or a custom underwriter limit. PMI is added automatically when the resulting down payment is under 20% of the affordable home price and dropped when it would be 20% or more, matching how conventional loans actually work. Property tax and home insurance are entered as annual percentages of the home value, so they scale with the price as you adjust other inputs. The result panel shows the maximum home price, the maximum financed loan, the full PITI plus HOA monthly breakdown, the binding cap (front-end or back-end DTI), the housing share of income, and the total debt share of income. A built-in rate stress test shows how the maximum home price moves at minus 1% through plus 1.5% from your entered rate, so you can see how much affordability changes between locking now and waiting for rates to move. Six preset scenarios cover the most common buyer profiles: first-time buyer with low down, median income household, dual-income with 20% down, condo with HOA, FHA-style relaxed DTI, and a conservative 15 year. Currency formatting supports USD, EUR, GBP, CAD, AUD, INR, and TRY for display only; no exchange rates are fetched. Every number is computed locally in your browser, so income, debts, and savings stay on your device. Useful for sizing a realistic home shopping budget, deciding whether to wait and save more or buy now, comparing how DTI caps differ across loan programs, sanity-checking what a loan officer prequalifies you for, and seeing whether stretching to a higher price still leaves headroom for life expenses. This is a planning estimate, not a lender approval; actual qualification depends on credit score, employment history, down payment source, cash reserves, property type, and program.

Free to use. Works in your browser. No signup, no login.