BYTETOOLS

Home Affordability Calculator

Find out how much house you can afford from your income, monthly debts and down payment, using the 28/36 debt-to-income rule with fully editable ratios.

$336,193
Home price you can afford
$296,193
Maximum loan
$2,333.33
Max monthly housing payment
Front-end ratio (housing only)
Limited by

How the monthly payment breaks down

Principal and interest
$1,872.14
Property tax
$336.19
Home insurance
$125.00
HOA / service charge
$0.00
Front-end ceiling (28%)
$2,333.33
Back-end ceiling (36% less debts)
$2,500.00

The 28/36 rule is a guideline, not a law — lenders, loan programmes and countries all use different limits, so both ratios are editable here. Mortgage insurance and utilities are not included. Estimates only, not financial advice.

What is the Home Affordability Calculator?

The ByteTools Home Affordability Calculator works backwards from what lenders actually test. It takes your gross income, existing monthly debt payments and target debt-to-income ratios, derives the largest housing payment you would qualify for, strips out taxes, insurance and HOA fees to leave the principal and interest, and then reverses the loan formula to find the maximum loan and home price.

  • Uses both front-end and back-end DTI limits, defaulting to the 28/36 rule
  • Shows which ratio is limiting you and by how much
  • Subtracts property tax, insurance and HOA before solving for the loan
  • Reverses the annuity formula to get the maximum loan and price
  • Fully editable thresholds for different loan programs and countries
  • Private, offline and free — income details never leave the page

How to use the Home Affordability Calculator

  1. 1

    Enter your gross annual household income and your existing monthly debt payments.

  2. 2

    Enter your down payment, the mortgage rate and the term.

  3. 3

    Add your property tax rate as a percent of value, annual home insurance and monthly HOA fees.

  4. 4

    Adjust the front-end and back-end DTI limits if your lender uses different ones.

  5. 5

    Read your maximum monthly payment, loan amount and home price.

About the Home Affordability Calculator

The ByteTools Home Affordability Calculator works backwards from what lenders actually test. It takes your gross income, existing monthly debt payments and target debt-to-income ratios, derives the largest housing payment you would qualify for, strips out taxes, insurance and HOA fees to leave the principal and interest, and then reverses the loan formula to find the maximum loan and home price.

The default limits are the classic 28/36 rule: no more than 28% of gross income on housing, and no more than 36% on all debt combined. Both are editable, because different loan programs and different countries use different thresholds — some allow 43% or more on the back-end ratio.

It shows which of the two ratios is the binding constraint, so you know whether paying down a car loan or raising your down payment would help more. Everything runs locally in your browser with nothing uploaded. Estimates only, not financial advice or a pre-approval.

Frequently asked questions

How much house can I afford on my salary?

Most lenders cap your housing payment at about 28% of gross monthly income and total debt at 36%. On $90,000 a year that is roughly $2,100 a month for housing, minus tax and insurance, which sets the loan you can support at current rates.

What is the 28/36 rule?

It is a lending guideline: spend no more than 28% of gross monthly income on housing costs (the front-end ratio) and no more than 36% on all debt payments combined (the back-end ratio). Many loan programs allow higher back-end ratios, which is why both figures are editable here.

Does my down payment change how much I can afford?

Yes, directly. Your income sets the maximum loan you can support; the down payment is added on top of that to give the maximum purchase price. A larger deposit also avoids mortgage insurance, freeing more of your payment for principal and interest.

Should I borrow the maximum I qualify for?

Usually not. Qualifying limits are based on gross income before tax and ignore childcare, savings, commuting and retirement contributions. Many buyers deliberately target 70% to 80% of their maximum to leave room for real life.

Is this the same as a mortgage pre-approval?

No. A pre-approval involves a credit check, income verification and a lender's own underwriting rules. This is a planning estimate that shows you the arithmetic lenders start from, so you can walk into that conversation prepared.

Related tools