Calculate a House Loan Payment With This Calculator

A house loan calculator estimates your monthly principal-and-interest payment from the loan amount, annual APR, and term. Enter those three figures to see the payment and the total interest over the full term; the estimate does not include taxes, insurance, or other housing costs.

Formula

The calculator uses the standard fixed-rate, fully amortizing loan payment formula:

Monthly payment = P × r ÷ [1 − (1 + r)⁻ⁿ]

• P is the amount borrowed, in dollars.
• r is the monthly interest rate as a decimal: APR ÷ 100 ÷ 12, or APR ÷ 1,200 when APR is entered as a percentage.
• n is the number of monthly payments: the term in years × 12.

Total interest is calculated as the monthly payment multiplied by the number of payments, minus the original loan amount. The payment formula assumes a positive APR and a level payment each month. The calculator displays the payment rounded to cents; the displayed total-interest result uses that displayed payment and may therefore differ slightly from a calculation using unrounded values.

Worked Example

Using the calculator’s default inputs—$20,000 borrowed at 8% APR for 5 years—the monthly rate is 8 ÷ 1,200 = 0.0066667, and the number of payments is 5 × 12 = 60.

1. Insert the inputs: $20,000 × 0.0066667 ÷ [1 − (1 + 0.0066667)⁻⁶⁰].
2. The monthly payment is approximately $405.53 after rounding to cents.
3. Total interest is $405.53 × 60 − $20,000 = $4,331.80.

These figures illustrate the calculation for the stated inputs; they are not a quote for a home loan.

Assumptions

• The interest rate remains fixed for the entire loan term.
• Payments are equal monthly payments made at the end of each monthly period.
• Interest compounds monthly using APR divided by 12.
• The estimate excludes lender fees, taxes, homeowners insurance, mortgage insurance (PMI), escrow, and other costs because they are not inputs to this calculator.

How to Use a House Loan Calculator

Enter the amount you expect to borrow, not necessarily the home’s purchase price. If you are estimating a purchase, the loan amount generally reflects the amount financed after accounting for any down payment and other amounts included in the loan. Use the APR and term shown in a lender’s loan estimate or other disclosure when you have them. For an early estimate, enter a clearly labelled assumption rather than treating an example rate as an offer.

• Loan amount: Enter the principal in dollars. The permitted range is $1 to $100,000,000.
• APR: Enter an annual percentage, such as 8 for 8%, not 0.08. The calculator accepts 0.01% to 100%.
• Term: Enter the length in years. For example, 30 means 360 monthly payments. The accepted range is approximately one month to 50 years.

Changing any input changes the estimate. A larger principal or higher APR increases the payment when the other inputs stay the same; extending the term generally lowers the scheduled monthly payment but means more payments are made. The precise effects depend on the combination of inputs.

What the Results Mean

The monthly payment is the scheduled amount covering principal and interest under the formula. Early in an amortizing loan, more of each payment goes toward interest; as the outstanding balance falls, the interest portion generally shrinks and the principal portion grows. The total-interest figure estimates the interest paid across all scheduled payments, assuming the loan is paid as planned with no extra payments or changes.

A house payment is not necessarily the same as the full monthly cost of owning a home. Property-related taxes, homeowners insurance, mortgage insurance, association charges, utilities, maintenance, and any escrow collection can affect cash outflow but are not calculated here. Some loans also have fees or payment structures that change the amount due. Obtain the applicable figures from the lender and include relevant housing costs separately when making a budget.

Common Mistakes and Limits

• Using the purchase price as the principal: Enter the amount financed. A down payment or other financing changes can make this different from the price.
• Entering APR as a decimal: Type 8 for 8%, not 0.08. The calculator converts the percentage to a monthly decimal internally.
• Mixing years and months: The term input is in years. Entering 30 represents 30 years, not 30 months.
• Assuming interest is the only housing expense: The result omits taxes, insurance, mortgage insurance, fees, and escrow.
• Treating rounded figures as exact: Payments are shown to cents. A lender’s schedule can differ because of payment dates, rounding conventions, fees, or loan terms not represented here.

This formula is for a fixed rate and regular monthly payments. It does not model adjustable rates, irregular payment timing, interest-only periods, balloon payments, extra principal payments, or refinancing. A separate calculation is needed when those features apply.

Frequently Asked Questions

How do I calculate a monthly house loan payment?
Convert the APR to a monthly decimal by dividing it by 1,200, convert the term to months, then use the fixed-payment formula shown above. The calculator performs those steps from the three inputs.

Does this calculator include property taxes and insurance?
No. It estimates principal and interest only. Add taxes, homeowners insurance, mortgage insurance, and other applicable charges separately using figures relevant to the property and loan.

Is APR the same as the interest rate?
Not always. APR is a yearly percentage measure that may reflect certain borrowing costs as well as interest, depending on the loan and its disclosure. The calculator treats the entered APR as the rate used in its payment formula, so it may not reproduce a lender’s payment if fees or other terms are handled differently.

Why does a longer loan term usually show a lower monthly payment?
The principal is spread over more monthly payments. Because interest accrues for longer, the total interest across the full term can be higher even when the scheduled payment is lower.

Will this result match a lender’s exact payment?
Not necessarily. The estimate excludes fees and housing costs and assumes a fixed rate with regular monthly payments. Check the lender’s disclosure for the exact payment and loan terms.

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

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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