Mortgage Payment Calculator
Monthly payment, total paid, and total interest for a fixed-rate loan, with the exact formula.
What it does
A fixed-rate mortgage splits each monthly payment into interest and principal. Early on, most of the payment covers interest. With every payment the balance falls, so the interest share shrinks and the principal share grows, while the payment itself stays flat.
The tool above prices that schedule from three inputs: amount borrowed, annual rate, and term in years. It returns the fixed monthly payment of principal and interest, the lifetime total, and the lifetime interest.
Taxes, insurance, and fees sit outside this math. Lenders often collect them monthly on top of principal and interest, so treat the result as the loan part of the housing cost, not the full monthly bill.
How to use
- Enter the amount you borrow, which is the price minus the down payment.
- Enter the annual rate as a percent, for example 6.5.
- Enter the term in years. Thirty and fifteen are the common choices.
- Compare the monthly payment against your budget and the total interest across terms.
Formula
- P
- Amount borrowed after the down payment.
- r
- Monthly rate: annual rate divided by 12.
- n
- Payment count: years times 12.
Divide the annual rate by 12 to get the monthly rate before anything else. When the rate is zero, the formula collapses to principal divided by number of payments. Each month, interest equals the current balance times r, and the rest of the payment cuts principal.
Worked example
Example: $250,000 at 6.5% for 30 years
Principal 250,000, annual rate 6.5%, term 30 years means 360 payments.
- Monthly rate: 0.065 / 12 = 0.00541667.
- Growth factor: (1.00541667)^360 = 6.9918.
- Monthly payment: 250,000 x 0.00541667 x 6.9918 / 5.9918 = $1,580.17.
- Lifetime total: 1,580.17 x 360 = $568,861.22.
- Lifetime interest: 568,861.22 - 250,000 = $318,861.22.
Reference table
| Term | Monthly payment | Lifetime interest |
|---|---|---|
| 30 years | $1,580.17 | $318,861.22 |
| 20 years | $1,863.93 | $197,343.88 |
| 15 years | $2,177.77 | $141,998.31 |
Limits
- Principal and interest only. Escrow items excluded.
- Fixed rate assumed. Adjustable loans reset later.
- Ignores points, fees, and mortgage insurance.
- Prepayments and recasts change the schedule.
Common mistakes
- Forgetting property tax and insurance, which can add hundreds per month on top.
- Comparing rates without comparing points and fees, which change the true cost.
- Extending the term for a lower payment without checking how much lifetime interest rises.
- Entering the house price instead of the amount borrowed after the down payment.
- Assuming adjustable rates follow this math past the first fixed period.
Try it yourself
Quick checks. Answers sit tucked under each question.
Monthly payment on $300,000 at 7% for 30 years?
r = 0.00583333, n = 360. M = $1,995.91.
Zero percent loan of $120,000 over 10 years?
120,000 / 120 = $1,000 a month, all principal.
Questions
What does the monthly payment include?
Only principal and interest. Property tax, home insurance, mortgage insurance, and HOA dues are billed separately or escrowed on top.
Why is the first payment mostly interest?
Interest equals the full balance times the monthly rate, which is largest at the start. As the balance falls, the same payment covers more principal.
Is a 15 year loan always better?
It charges far less interest but demands a higher payment. It suits buyers with room in the budget; others may prefer the 30 year term with extra principal payments when possible.
What happens with extra payments?
Extra money goes to principal and shortens the loan, which cuts lifetime interest. Ask the servicer to apply it to principal, not as an early regular payment.
Does this work for car or personal loans?
Yes, for any fixed-rate amortizing loan. Enter the amount, rate, and term in years and the same formula applies.