How is a mortgage payment calculated?

Using the amortization formula M = P × r(1+r)^n ÷ ((1+r)^n − 1), where P is the loan amount, r the monthly rate, and n the number of payments.

What is included in the monthly payment?

This calculator shows principal and interest. Your actual payment may also include property tax, homeowners insurance, PMI, and HOA dues.

Should I choose a 15-year or 30-year mortgage?

A 15-year loan has higher monthly payments but much lower total interest. A 30-year loan is more affordable monthly but costs more overall.

How does the down payment affect my mortgage?

A larger down payment reduces the loan amount, lowering both the monthly payment and total interest, and may help you avoid mortgage insurance.

Does a small rate change really matter?

Yes. Over a 30-year term, even a 0.5% rate difference can change total interest by tens of thousands of dollars.

What is amortization?

Amortization is how each payment is split between interest and principal. Early payments are mostly interest; later ones pay down more principal.

Mortgage Calculator

Calculate monthly mortgage payments.

Input & results

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Results

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Calculation History

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Recent calculations are saved automatically as you adjust inputs.

Financial results are estimates for informational purposes only and are not financial, tax, or investment advice. Verify figures with a qualified professional before making decisions. See our full disclaimer.

What is Mortgage?

A Mortgage Calculator estimates the monthly payment on a home loan, combining principal and interest, so you can judge affordability and compare financing options before buying property.

A mortgage is a long-term loan secured against property, usually repaid over 15 to 30 years. Each monthly payment covers interest on the outstanding balance plus a portion of principal, gradually building equity. This calculator applies the standard amortization formula to your loan amount, interest rate, and term to show the monthly payment, total interest, and total cost of the loan.

Why is it used?

Your mortgage payment is often the largest recurring expense in your budget. Estimating it in advance helps you set a realistic home-price range, compare lenders, and understand how rate and term changes affect both the monthly payment and the total interest paid.

Who should use it?

Home buyers, homeowners considering refinancing, and property investors evaluating financing on a purchase.

How it works

Enter Loan Amount, Annual Interest Rate (%), Loan Term (years) in the input fields.
The calculator validates your entries and applies the correct mortgage formula.
Results update in real time as you change any value — no submit button needed.
Review the formula, variable definitions, and worked example below to see how the answer is derived.

Formula

M = \frac{P \times r ( 1 + r ) ^{n}}{( 1 + r ) ^{n} - 1}

Variable definitions

Variable	Meaning
M	Monthly mortgage payment
P	Loan amount (principal)
r	Monthly interest rate = annual rate ÷ 12 ÷ 100
n	Total number of payments (years × 12)

How the formula works

Convert the annual interest rate to a monthly rate r.
Set n to the loan term in months (years × 12).
Apply M = P × r × (1 + r)^n ÷ ((1 + r)^n − 1).
Total interest = (M × n) − P.

Example calculation

A $300,000 mortgage at 6.5% annual interest over 30 years.

Input	Value
Loan amount	$300,000
Annual rate	6.5%
Term	30 years

r = 6.5 ÷ 12 ÷ 100 = 0.005417
n = 30 × 12 = 360
M = 300000 × 0.005417 × (1.005417)^360 ÷ ((1.005417)^360 − 1)
M ≈ $1,896

Result

Monthly payment ≈ $1,896; total interest ≈ $382,633 over 30 years.

More examples

Same loan over a 15-year term.

Input	Value
Loan amount	$300,000
Annual rate	6.5%
Term	15 years

r = 0.005417, n = 180
M ≈ $2,613

Result

≈ $2,613/month — higher payment, far less total interest.

Methodology

Gather Loan Amount, Annual Interest Rate (%), Loan Term (years) from your documents or estimates.
Enter each value in the matching field; units must match the labels.
The calculator applies the Mortgage formula and updates results in real time.
Compare scenarios by changing one input at a time.

Benefits

Estimate your monthly housing payment before house hunting.
Compare 15-year vs 30-year terms and their interest cost.
See how rate changes affect affordability.
Understand the total cost of a property purchase.

Use cases

First-time buyers setting a budget.
Refinancing comparisons at a new rate.
Investors evaluating rental property financing.
Deciding between loan terms.

Tips & important notes

Property tax, insurance, and HOA fees are usually on top of principal and interest.
A larger down payment lowers the loan amount and monthly payment.
A shorter term saves substantial interest despite higher payments.
Even a small rate difference adds up over 30 years.

Common mistakes

Forgetting taxes and insurance, which raise the true monthly cost.
Using the annual rate directly instead of a monthly rate.
Focusing only on the monthly payment, not total interest.

Related concepts

Amortization and equity buildup
Down payment and loan-to-value ratio
Fixed vs adjustable-rate mortgages

Good to know

This estimate covers principal and interest only. Property taxes, homeowners insurance, PMI, and HOA fees are additional. Confirm exact figures with your lender.