15-Year vs. 30-Year Mortgage: A Side-by-Side Cost Breakdown

Choosing a loan term is one of the biggest decisions in a mortgage, yet many buyers default to 30 years without running the numbers. Here's a clear comparison of what each term costs and who each one suits.

Side-by-side example on a $300,000 loan

These figures use illustrative rates: 6.5% for a 30-year fixed and 5.75% for a 15-year fixed. Fifteen-year rates are usually lower than 30-year rates, though the exact gap varies.

The 15-year loan costs about $595 more per month but saves more than $230,000 in interest. It also builds equity much faster. After five years, the 15-year borrower has paid down far more principal than the 30-year borrower.

Why 15-year loans cost so much less

1. Lower rate: lenders take less risk over a shorter period, so they charge less.
2. Faster principal reduction: each payment chips away more of the balance, so interest is charged on a smaller amount sooner.
3. Fewer years of interest: half as many payments means half as many months for interest to accumulate.

Who a 15-year mortgage fits

• Buyers with stable, high income who can comfortably afford the larger payment and still save for retirement and emergencies.
• Homeowners refinancing later in their careers who want to be debt-free by retirement.
• People who value guaranteed savings over investment flexibility.

Who a 30-year mortgage fits

• First-time buyers stretching to afford a home.
• Households with variable income who want a low required payment.
• Borrowers who prefer to invest extra money elsewhere or build emergency savings.
• Anyone who wants the flexibility to pay extra when they can, without being required to.

The middle path: 30-year loan, 15-year habits

Most mortgages allow extra principal payments without penalty. If you take a 30-year loan but pay an extra amount each month toward principal, you can shorten the term substantially while keeping the lower required payment as a safety net. You won't get the lower 15-year rate, though, so you'll pay somewhat more interest than a true 15-year loan. Our guide to paying off your mortgage early shows how.

What about 20-year and 10-year terms?

Many lenders offer 10-, 20- and 25-year fixed terms. A 20-year loan is a useful compromise, with a payment between the two and significant interest savings over 30 years. Ask lenders to quote multiple terms side by side.

A quick decision framework

If you're torn between terms, work through these questions in order:

1. Is the 15-year payment under about 25% of your take-home pay? If not, the 30-year term is usually the safer choice.
2. Do you have an emergency fund of at least three to six months of expenses? A higher required payment leaves less room for surprises.
3. Are you contributing enough to retirement to get any employer match? Skipping a 401(k) match to pay down a mortgage faster usually costs more than it saves.
4. Do you carry high-interest debt? Credit cards and personal loans should generally be paid off before you commit to a higher mortgage payment.
5. How stable is your income? Commission, seasonal, or single-income households benefit from the flexibility of a lower required payment.

If you answered yes to the first four and your income is stable, the 15-year loan is likely a strong choice. Otherwise, a 30-year loan with optional extra principal payments gives you most of the benefit without the risk.

Equity after five and ten years

Using the same $300,000 example, the 15-year borrower would owe roughly $227,000 after five years and roughly $130,000 after ten. The 30-year borrower would owe roughly $281,000 after five years and roughly $254,000 after ten. That faster equity build gives the 15-year borrower more options to refinance, borrow against the home or sell profitably if plans change.