Mortgage payment & affordability calculator
Enter a home price, down payment, interest rate and term to see the monthly principal-and-interest payment, computed with the standard amortization formula. The rate is pre-filled with the current Freddie Mac PMMS 30-year average of 6.47% (June 18, 2026); change it to your quoted rate. The second tool works backward from a monthly budget to the loan amount it supports. Everything runs in your browser. It covers principal and interest only — it excludes property tax, insurance, HOA and PMI, so it is an estimate, not lending advice.
Source: Freddie Mac Primary Mortgage Market Survey (PMMS). Data as of June 18, 2026.
How it works
The monthly payment on a fixed-rate loan is the amount that fully repays the principal plus interest over the term. The formula is transparent and documented on our methodology page:
M = P × r(1+r)n ÷ ((1+r)n − 1)
where P is the loan amount (home price minus down payment), r is the monthly
rate (APR ÷ 12) and n is the number of monthly payments (years × 12). The
affordability tool inverts the same formula to solve for P from a monthly payment.
Frequently asked questions
How is the monthly mortgage payment calculated?
It uses the standard fixed-rate amortization formula: M = P × r(1+r)^n ÷ ((1+r)^n − 1), where P is the loan amount (home price minus down payment), r is the monthly interest rate (APR ÷ 12) and n is the number of months. The result is principal and interest only — it excludes property tax, homeowner's insurance, HOA dues and mortgage insurance (PMI/MIP).
What rate should I use?
The calculator is pre-filled with the Freddie Mac PMMS 30-year fixed average of 6.47% (as of June 18, 2026), but you should enter the rate you are actually quoted. National averages assume a strong borrower; your rate depends on credit, down payment, loan type and lender.
What does the affordability estimate show?
It runs the amortization formula in reverse: given a monthly principal-and-interest budget, a rate and a term, it solves for the largest loan amount that fits. Add your down payment to get the total home price. It does not account for taxes, insurance, PMI, or lender debt-to-income limits, so treat it as a ceiling, not an approval.
Is this financial advice?
No. RateLedger is an informational tool. The calculator gives a transparent estimate of principal and interest only. For a real figure, get a Loan Estimate from a licensed lender, which includes taxes, insurance and all fees.
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Last updated: 2026-06-20