Free tool for home buyers
Home affordability and monthly payment calculator
Monthly payment = loan principal and interest + property tax + insurance + HOA dues. A common guideline caps housing at 28% of gross monthly income and housing plus other debts at 36%. The example is an estimate, not advice: a $400,000 home with 20% down at 6.5% over 30 years has $2,022.62 of principal and interest and about $2,539.28 a month in all; on $120,000 of income and $500 of other debts the guideline allows $2,800 a month, a price of about $443,647.
Last updated 2026-11-04.
- Estimated monthly payment (all-in)
- Principal and interest
- Property tax, insurance and HOA a month
- Down payment in dollars
- Loan amount
- Housing share of gross income
- Housing plus other debts, share of income
- Price a 28/36 guideline allows
- Most a month on housing under the guideline
- Which limit applies
Check the inputs: price above 0, down payment 0 to 100%, term above 0, no negative amounts.
Example scenarios
Three sets of example inputs worked through the same formulas as the calculator above. They are illustrations, not averages or statistics.
| Scenario | Inputs ($400,000 home basis: 20% down, 6.5%, 30 years, $500 debts) | Most a month on housing | Price the guideline allows | Limit that applies |
|---|---|---|---|---|
| Low | $90,000 income a year | $2,100.00 | $326,458 | 28% of income |
| Typical | $120,000 income a year | $2,800.00 | $443,647 | 28% of income |
| High | $150,000 income a year | $3,500.00 | $560,837 | 28% of income |
Method: Principal and interest = standard fixed-rate formula on (price − down payment); monthly payment = principal and interest + property tax ÷ 12 + insurance ÷ 12 + HOA; the 28/36 guideline allows the smaller of 28% of gross monthly income and 36% of it minus other debts, and the price is the one whose payment equals that amount. A common rule of thumb, an estimate, not advice. Figures checked against the same formulas on 2026-11-04.
Important: an estimate, not advice
This calculator does arithmetic on the numbers you type. A lender looks at your credit, savings, the exact loan type, local taxes and more, so a real offer can differ a lot. The 28% and 36% limits are a common rule of thumb, not a rule that every lender or buyer follows, and the result is not financial, mortgage or legal advice. Check your figures with a lender or a housing counselor before you make an offer.
How the monthly payment is worked out
The loan is the price minus the down payment. Principal and interest use the standard fixed-rate mortgage formula for your rate and term. Property tax is entered as a share of the price per year and divided by 12, homeowners insurance is entered per year and divided by 12, and HOA dues are entered per month. The all-in payment is the sum of the four. It leaves out private mortgage insurance, which many lenders require when the down payment is under 20%, utilities, repairs and closing costs, so treat it as a floor, not a ceiling.
How the 28/36 guideline gives a price
Take gross monthly income, which is the yearly figure divided by 12. The front limit is 28% of it for housing. The back limit is 36% of it minus your other monthly debt payments, such as a car loan, student loans and card minimums. The guideline allows the smaller of the two. The calculator then finds the price at which principal and interest, tax, insurance and HOA together fit that monthly amount, using your down payment share, rate and term.
Worked example
Price $400,000, 20% down ($80,000), 6.5% interest, 30 years: the loan is $320,000 and principal and interest are $2,022.62 a month. Property tax at 1.1% of the price is $4,400 a year ($366.67 a month), insurance is $1,800 a year ($150), and there are no HOA dues. The all-in payment is 2,022.62 + 366.67 + 150 = $2,539.28, which is 25.4% of a $10,000 monthly income and 30.4% once $500 of other debts are added.
With $120,000 of income and $500 of debts, the front limit is 28% of $10,000 = $2,800 and the back limit is 36% of $10,000 minus $500 = $3,100. The smaller one is $2,800, and that monthly amount supports a price of about $443,647 with the same down payment share, rate, term, tax and insurance.
When debts set the limit
Keep everything the same but raise other monthly debts to $2,000. The front limit is still $2,800, but the back limit falls to 36% of $10,000 minus $2,000 = $1,600, so the 36% limit applies and the guideline supports a price of only about $242,751. Paying down a car loan or student loan can raise what the guideline allows by more than a bigger down payment would.
What this tool does not do
It does not know your credit score, your loan type, mortgage insurance, closing costs, moving costs, or what the home needs after you buy it. It also does not tell you what you should spend: many buyers keep a smaller payment than a guideline allows so that they have room for savings and repairs. The planned product linked below is a different thing, an assistant that helps you contact listing agents and keep track of viewings, and it is not available yet.
Questions
What is the 28/36 rule?
A common guideline: spend at most 28% of gross monthly income on housing and at most 36% on housing plus other debts. It is a rule of thumb, not a requirement.
Does the payment include mortgage insurance?
No. If your down payment is under 20% a lender may add private mortgage insurance, which this estimate leaves out.
Is this financial advice?
No. It is an estimate based on the numbers you type and is not mortgage, financial or legal advice.
Does this page store my numbers?
No. The math runs in your browser; nothing is sent or saved.
Made by Bardach Technologies. We are planning Viewingshub, an assistant for home buyers that drafts a note to each listing agent for you to approve and tracks your viewings and replies. It is not available yet: the planned page has a free waitlist, and nothing is charged on this page or there. See the planned product