15 vs 30 Year Mortgage Calculator
Enter a loan amount and the interest rate for each term. You see the monthly payment, the total interest and the balance after five years of a 15-year and a 30-year mortgage, side by side.
By Muhammad AhmadLast reviewed Oct 19, 2026Free, no sign-up
Estimate, not financial or tax advice. The result is only as good as the numbers you enter and the assumptions listed below the calculator. Rates, tax rules and lender terms change, so check big decisions with the official source or a licensed professional. See the disclaimer.
Example Calculation
Take a $300,000 loan with the rates in Freddie Mac's weekly survey for the week of October 8, 2026: 7.40% for a 30-year fixed loan and 6.73% for a 15-year fixed loan. The 30-year payment is $2,077 a month and the 15-year payment is $2,651, which is $574 more. Over the life of the loans the 30-year mortgage costs $447,770 of interest and the 15-year mortgage $177,253, so the shorter loan saves about $270,518.
Payment and interest by loan amount
Principal and interest only, at 7.40% for 30 years and 6.73% for 15 years.
| Loan amount | 30-year payment | 15-year payment | Extra each month | 30-year interest | 15-year interest | Interest saved |
|---|---|---|---|---|---|---|
| $200,000 | $1,385 | $1,768 | $383 | $298,513 | $118,168 | $180,345 |
| $300,000 | $2,077 | $2,651 | $574 | $447,770 | $177,253 | $270,518 |
| $400,000 | $2,770 | $3,535 | $766 | $597,027 | $236,337 | $360,690 |
| $500,000 | $3,462 | $4,419 | $957 | $746,284 | $295,421 | $450,863 |
How It Works
The term of a mortgage is the number of years you have to repay it. A 30-year loan spreads the balance over 360 payments, so each payment is small, but the lender charges interest on a large balance for a long time. A 15-year loan has 180 payments. Each one is bigger, the balance falls much faster and the total interest is far lower. The 15-year rate is also usually lower than the 30-year rate, which adds to the saving.
Type the loan amount, then the rate you were quoted for each term. If you do not have quotes yet, the Freddie Mac survey is a fair starting point; your own rate depends on your credit, your down payment and the lender. The calculator shows both payments, how much more the 15-year loan costs each month, the total interest of each loan and how much you still owe after five years.
The cheaper loan is not always the better choice. A payment you can only just make leaves no room for a job loss or a repair, and money tied up in the house cannot go into an emergency fund or retirement saving. Some buyers take the 30-year loan and pay extra when they can: the loan then ends sooner, and the payment stays low in a bad month. The mortgage payoff calculator shows what extra payments do.
This calculator covers principal and interest only. Property tax, home insurance and mortgage insurance are added on top of both loans, so use the mortgage calculator to see the full monthly cost of each.
Formula Explained
Monthly payment: payment = loan × r ÷ (1 - (1 + r)^-n), where r is the yearly rate divided by 12 and n is the number of payments (360 or 180).
Total interest: payment × n - loan. Balance after k payments: loan × (1 + r)^k - payment × ((1 + r)^k - 1) ÷ r.
Assumptions and limits
- Fixed rates for the whole term. An adjustable-rate loan changes its payment over time, so the result is only a guide for it.
- Principal and interest only. Property tax, insurance, PMI, HOA dues, closing costs and fees are not included.
- The 15-year loan and the 30-year loan are for the same amount, with no extra payments. Payments are made monthly and on time.
- The default rates (7.40% and 6.73%) are national averages from the Freddie Mac survey for the week of October 8, 2026. Your rate depends on your credit, your down payment and the lender.
Frequently Asked Questions
Is a 15-year or a 30-year mortgage better?
The 15-year loan costs far less in interest and builds equity faster, but the payment is higher. The 30-year loan has a lower payment and more room in a bad month. The better one is the loan whose payment you can make comfortably while you still save for emergencies and retirement.
How much higher is the payment on a 15-year mortgage?
On a $300,000 loan at 7.40% for 30 years and 6.73% for 15 years, the payment is $2,651 against $2,077, which is $574 more each month. The gap grows with the loan amount: about $383 on $200,000 and about $957 on $500,000.
How much interest does a 15-year mortgage save?
On the same $300,000 loan the 15-year mortgage costs $177,253 of interest against $447,770 for the 30-year mortgage, a saving of about $270,518. Part of that comes from the shorter term and part from the lower rate.
Why is the 15-year rate lower than the 30-year rate?
A shorter loan is less risky for the lender, who gets the money back sooner. In the Freddie Mac survey used here the gap was 0.67 percentage points. The gap changes from week to week and from lender to lender.
Can I pay off a 30-year mortgage in 15 years?
Yes, by paying extra principal. On the $300,000 example, paying the 15-year amount of about $2,651 on the 30-year loan ends it in about 16 years and 3 months, with about $216,000 of interest. A real 15-year loan is still cheaper, because its rate is lower. The mortgage payoff calculator shows your own numbers.
Which loan builds equity faster?
The 15-year loan, by a lot. On the $300,000 example you still owe about $231,116 after five years on the 15-year loan, against about $283,569 on the 30-year loan.
Does this include taxes, insurance and PMI?
No. It shows principal and interest only. Property tax, home insurance, PMI and HOA dues are added on top of both loans. The mortgage calculator includes them.
Should I take a 15-year mortgage if I can only just afford it?
Usually not. A payment you can only just make adds risk. A 30-year loan with extra payments gives you the same speed in good months and room in bad ones.
Which interest rates should I enter?
Use the rates from your lender's loan estimate for each term. If you only want to compare, the weekly Freddie Mac Primary Mortgage Market Survey shows national averages for 30-year and 15-year fixed loans.
Think a number is wrong? Tell me what you typed and what you expected, and I will check it.
Methodology and sources
Each payment comes from the standard amortization formula for a fixed-rate loan, with monthly interest on the remaining balance. Total interest is the sum of all payments minus the loan. The balance after five years is the amount still owed after 60 payments. The default rates are the Freddie Mac survey averages for the week of October 8, 2026.
- Primary Mortgage Market Survey (average mortgage rates), Freddie Mac
- Buying a house, Consumer Financial Protection Bureau
- Loan Estimate explainer, Consumer Financial Protection Bureau
Last reviewed Oct 19, 2026 by Muhammad Ahmad. The page is checked again when the source figures change and at least once a year. See the corrections log, or report a mistake.
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