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15-year vs 30-year mortgage calculator

What the shorter term costs a month, and what it saves in interest.

Reviewed by Victor Yuki Matusita on . First published .

Your numbers stay on your device
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15-year payment

$2,613.32/mo

B costs $717 more a month and saves $212,238 of interest.

  • Principal $300,000 · 64%
  • Interest over 15 years $170,398 · 36%

30-year fixed
Monthly payment
$1,896
Total interest
$382,637
Paid off in
30 years
15-year fixed
Monthly payment
$2,613
Total interest
$170,398
Paid off in
15 years

B costs $717 more a month and saves $212,238 of interest.

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Balance by year, both terms

How to use the 15-year vs 30-year calculator

  1. Enter the home price and the down payment.
  2. Type the rate you were quoted for each term; shorter terms are often quoted lower.
  3. Compare the payment and the interest of the two loans, and open the balance by year.

What the shorter term trades

Repaying the same amount in half the time means a larger payment each month, but the balance falls much faster, so far less interest builds up. A lower rate on the 15-year loan widens the gap in interest.

Questions to ask yourself

Would the larger payment still fit if your income dropped for a while? Would you rather keep the 30-year payment and pay extra when you can? The extra payments calculator shows that middle path with the same loan.

How the two loans are worked out

The formula

Each payment is M = P × r × (1 + r)^n ÷ ((1 + r)^n − 1), with P the loan, r the yearly rate of that term divided by 12, and n = 180 or 360.

Each month, interest = balance × r rounded to the cent. The difference in interest is the 30-year total minus the 15-year total.

Assumptions

  • Both loans are fixed-rate, with equal monthly payments, for the same amount: the price minus the down payment.
  • Interest is charged once a month at the yearly rate divided by 12, on the balance, rounded to the cent; the last payment closes the balance.
  • Taxes, insurance, PMI and fees are left out, since they are the same for both terms.

Worked example

This is the example the calculator opens with, worked out by the same engine you use above.

You enter
Home price$375,000.00
Down payment20%
15-yr rate6.5%
30-yr rate6.5%
You get
15-year payment$2,613.32
30-year payment$1,896.20
15-year total interest$170,398.28
30-year total interest$382,636.71
Loan amount$300,000.00

B costs $717 more a month and saves $212,238 of interest.

Sources

Read the guide: 15-year vs 30-year mortgage: the real cost

Educational tool

This calculator is an educational tool, not financial advice and not a loan offer. Lenders quote rates for each term.

Questions about 15-year and 30-year mortgages

Why is the 15-year payment not double the 30-year one?

Because the 30-year payment is mostly interest at the start. Halving the time removes much of that interest, so the payment grows by less than double.

Can I use the same rate for both?

Yes. Typing the same rate isolates the effect of the term alone; typing the rates you were quoted shows the real offers.

What about the down payment and PMI?

The loan amount is the same for both terms, so PMI, tax and insurance do not change the comparison. The mortgage calculator adds them to the payment.

Does the table show both loans?

Yes: what is still owed on each loan at the end of each year, so you can see how fast each one falls.

Privacy

Your numbers stay on your device. The calculator runs in your browser, so nothing you type is sent anywhere, and the link you copy keeps the numbers after the #, a part of the address your browser never sends.