How it works
How this tool works.
A mortgage payment is more than a monthly number — it’s a decades-long commitment where the interest can rival the price of the home itself. Seeing the monthly payment and the lifetime cost side by side makes the trade-offs concrete before you sign.
Enter the home price, your down payment, the interest rate, and the term, and this calculator estimates the monthly principal & interest along with the total interest and total paid over the life of the loan. It’s arithmetic on the figures you provide — an illustration, not a loan offer or a rate quote.
Enter the home price and set your down-payment percentage; the loan amount is the price minus the down payment.
Set the interest rate (APR) and loan term in years — the tool converts them to a monthly rate and a payment count.
It applies the standard amortization formula — M = P·r·(1+r)ⁿ ÷ ((1+r)ⁿ − 1) — to get the monthly principal & interest (a 0% rate simply spreads the loan evenly).
Total paid is the monthly payment across every month of the term; total interest is that figure minus the amount borrowed. Every output is an estimate from your inputs.
Make the result useful
Mortgage payment decisions
Loan amount is the principal actually financed, not the purchase price.
Interest rate is the note rate for the modeled loan; compare the same term when testing rates.
Loan term is the amortization length in years; taxes, insurance, HOA, and utilities remain separate owner costs.
Use the payment result inside a full property budget before treating it as affordability or cash flow.
The assumptions that move this result
Loan amount
Principal borrowed after down payment.
Interest rate
Annual note rate entered for the scenario.
Term
Amortization years, converted to monthly payments.
principal-and-interest payment from loan amount, rate, and term
Use the output as a documented scenario result, not a guarantee.
Read the number in context
Worked scenario
Scenario: a $240,000 30-year loan payment changes materially when rate changes, even if principal is unchanged.
Edge case
Edge case: a zero-rate loan is straight principal division; an adjustable loan needs separate future-rate scenarios.
The output excludes taxes, insurance, escrow, fees, and future rate changes.
Before you act
• Confirm whether the rate is fixed or adjustable.
• Add every owner-paid cost before comparing with rent.
• Check lender estimates for real closing and payment terms.
Worked formula
principal-and-interest payment from loan amount, rate, and term
Is this a forecast?
No. It calculates the assumptions you enter.
Can it replace professional review?
No. Use current records and qualified advice.
What should I save?
Keep the assumptions and source records used for the decision.