30-Year Mortgage to 15-Year Calculator

Refinancing your 30-year mortgage to a 15-year mortgage can significantly reduce your interest payments and pay off your home faster. This calculator helps you compare the savings and monthly payments between the two loan terms.

How This Calculator Works

The calculator compares two mortgage scenarios: keeping your existing 30-year mortgage or refinancing to a 15-year term. It calculates:

Monthly payments for both loan terms
Total interest paid over the life of the loan
Total amount paid (principal + interest)
Savings in interest payments

Monthly Payment Formula

The monthly payment is calculated using the standard mortgage formula:

M = P [ i(1 + i)^n ] / [ (1 + i)^n - 1 ]

Where:

M = Monthly payment
P = Principal loan amount
i = Monthly interest rate (annual rate divided by 12)
n = Number of payments (360 for 30-year, 180 for 15-year)

The calculator uses the same principal amount and interest rate for both scenarios to provide an accurate comparison.

How to Use This Calculator

Enter your current mortgage amount (principal)
Enter your current interest rate (APR)
Click "Calculate" to see the comparison
Review the results and savings

Note: This calculator assumes you're refinancing at the same interest rate. In reality, you might qualify for a lower rate when refinancing.

Example Calculation

Let's say you have a $200,000 mortgage at 4.5% APR. Here's what the calculator would show:

Term	Monthly Payment	Total Interest	Total Paid
30-Year	$1,073.64	$172,472.00	$372,472.00
15-Year	$1,492.16	$103,684.00	$303,684.00

In this example, refinancing to a 15-year term would save you $68,788 in interest payments and pay off your home $68,788 faster.

30-Year vs 15-Year Mortgage Comparison

Here's a general comparison of the two loan terms:

Feature	30-Year Mortgage	15-Year Mortgage
Term Length	30 years	15 years
Monthly Payments	Lower	Higher
Total Interest Paid	Higher	Lower
Total Amount Paid	Higher	Lower
Refinancing Flexibility	More options	Fewer options
Interest Rate Impact	Less sensitive	More sensitive

The 15-year mortgage is particularly beneficial when interest rates are expected to rise, as the shorter term means you'll be locked in for a shorter period.

Frequently Asked Questions

Is refinancing to a 15-year mortgage always a good idea?

Not necessarily. While you'll pay less in interest, you'll pay more each month. Consider your financial situation, whether you plan to stay in the home long-term, and if you can afford the higher monthly payments.

What are the closing costs for refinancing?

Refinancing typically costs 2-5% of the loan amount in closing costs, which may include appraisal fees, title insurance, and other fees. These costs can offset some of your savings.

Can I refinance to a 15-year mortgage if I have good credit?

Yes, but lenders may require a higher down payment (typically 10-20%) and may charge higher interest rates than conventional loans. Check with multiple lenders to find the best terms.

What happens if interest rates rise after I refinance?

With a 15-year mortgage, you're locked in for a shorter period, so rising rates won't affect you as much as with a 30-year mortgage. However, you may not be able to refinance again for several years.