House Loan Estimate Calculator: Monthly Payment & Costs

A house loan estimate calculator shows the estimated monthly principal-and-interest payment and total interest for a fixed-rate home loan. Enter the loan amount, annual interest rate, and term; the results do not include property taxes, homeowners insurance, mortgage insurance, or other housing costs.

Formula

The calculator uses the standard fixed-payment loan formula. It first calculates the monthly payment from the principal, monthly interest rate, and number of monthly payments:

Payment = P × r ÷ [1 − (1 + r)⁻ⁿ]

• P is the loan principal in dollars: the amount borrowed, not necessarily the home’s purchase price.
• r is the monthly interest rate as a decimal. The calculator converts the annual percentage rate (APR) using r = APR ÷ 1,200.
• n is the total number of monthly payments, calculated as the term in years multiplied by 12.

Total interest is estimated as monthly payment × n − P. The calculator’s displayed payment is rounded to cents, and total interest uses that displayed rounded payment. Real loan documents may have adjustments for payment dates, rounding, fees, or other contract details.

Worked Example

Using the calculator’s defaults—$20,000 borrowed, 8% APR, and a five-year term:

1. Convert the annual rate to a monthly decimal: 8 ÷ 1,200 = 0.0066667.
2. Find the number of payments: 5 × 12 = 60.
3. Apply the payment formula: $20,000 × 0.0066667 ÷ [1 − (1 + 0.0066667)⁻⁶⁰] ≈ $405.53 per month.
4. Estimate total interest using the rounded payment: $405.53 × 60 − $20,000 = $4,331.80.

For these inputs, the estimated monthly principal-and-interest payment is $405.53, and estimated total interest is $4,331.80.

Assumptions

• The interest rate stays fixed for the full loan term.
• Payments are made monthly, with the first payment one month after the loan begins.
• Interest is treated as compounding monthly at APR divided by 12.
• The calculation excludes fees, taxes, homeowners insurance, mortgage insurance, escrow, and any other charges because they are not inputs.

What a House Loan Estimate Includes

“House loan estimate” can refer to either a quick payment calculation or a fuller estimate of the cost of buying a home. This calculator addresses the loan’s principal-and-interest payment and total interest. It does not estimate a complete monthly housing budget or the cash required at closing.

The loan amount is different from the home price. For example, a buyer may use savings toward the purchase, so the borrowed principal is lower than the price. A lender’s estimate may also show fees and other transaction figures, but those depend on the loan offer and transaction. Enter the proposed amount borrowed—not the home’s price—if you want the payment calculation to represent the loan.

How to Use and Read the Results

• Loan amount: Enter the principal you expect to borrow, in dollars. Do not include a down payment as part of the loan unless it is actually financed.
• Interest rate: Enter the annual rate as a percentage, such as 6.5 for 6.5%. Use the rate supplied for the loan scenario; the default is only an example, not a market-rate claim.
• Loan term: Enter the repayment period in years. A longer term generally spreads repayment across more monthly payments; the formula’s result depends on the exact rate and term entered.
• Monthly payment: This is the estimated recurring payment for principal and interest only.
• Total interest: This is the estimated interest paid across all scheduled payments, not the total amount repaid. Add the principal to the interest to estimate the overall principal-and-interest outlay.

To explore a scenario, change one input at a time and compare the resulting payment and interest. For actual planning, use the figures supplied for the specific transaction and account for housing expenses not represented here. The calculator does not determine eligibility, approval, or what amount a person can afford.

Costs Outside the Payment and Common Mistakes

A house payment can include costs beyond principal and interest. Property taxes, homeowners insurance, mortgage insurance, association charges, maintenance, and lender or closing costs may affect the full cost of owning or financing a home. Which items apply, how they are collected, and their amounts vary by transaction. Get applicable figures from the relevant provider or loan documents rather than treating this calculator’s payment as an all-in housing cost.

• Entering the purchase price instead of the loan amount: This can overstate the calculated principal if part of the price is paid separately.
• Entering a whole-number rate incorrectly: For 6.5%, enter 6.5, not 0.065 or 650.
• Mixing years and months: The term field is in years; the formula converts years to monthly payments.
• Assuming APR captures every cost: This calculation uses APR as its interest-rate input but does not separately model fees, insurance, taxes, or escrow.
• Relying on an estimate as a quote: A calculator uses the inputs and assumptions shown. A lender’s transaction-specific disclosures provide the figures for that loan.

Limits and Related Calculations

The formula is for a level-payment loan with a fixed rate and equal monthly payments. It does not model a changing rate, an introductory period, irregular payment dates, skipped payments, extra principal payments, or a balloon payment. If a proposed loan has such features, this result will not reproduce its payment schedule.

For an adjustable-rate scenario, the eventual payment can change when the rate changes, so one fixed-rate calculation cannot represent the entire term. A separate amortization schedule can show how each payment is divided between interest and principal, while a closing-cost estimate needs transaction-specific fees and charges. Those calculations require additional inputs and are not included in this page’s result.

Frequently Asked Questions

Does this calculator show my full monthly house payment?
No. It estimates principal and interest. Taxes, insurance, mortgage insurance, escrow, and other housing costs are not included.

Should I enter the home price or the loan amount?
Enter the amount borrowed. If the purchase price and borrowed amount differ, using the purchase price will not represent the loan unless the full price is financed.

Why does the total interest use the rounded monthly payment?
The calculator rounds the payment to cents and multiplies that displayed amount by the number of payments, then subtracts principal. A real servicer may apply its own rounding and payment-accounting rules.

Can this estimate an adjustable-rate mortgage?
Not over a full term when the rate may change. The formula assumes the entered rate remains fixed for every monthly payment.

Does a lower payment mean less total interest?
Not necessarily. The result depends on both the rate and term, and a longer repayment period can involve more scheduled payments. Compare the displayed payment and total interest for the exact inputs rather than judging by payment alone.

This result is an estimate, and the lender’s disclosure gives the exact figures.

Related

• Home Equity Loan Calculator: Amount Up to a CLTV Limit and Payment
• Mortgage Calculator With Escrow: Payment With Tax and Insurance
• Mortgage Loan Amount Calculator: The Loan a Monthly Payment Repays

in p | Loan amount | $ | 20000 | 1 | 100000000
in apr | Interest rate (APR) | % | 8 | 0.01 | 100
in yrs | Loan term | years | 5 | 0.0833 | 50
out pmt | Monthly payment | $ | p * (apr / 1200) / (1 - (1 + apr / 1200) ^ -(yrs * 12)) | 2
out int | Total interest | $ | pmt * yrs * 12 - p | 2