15 vs. 30 Year Mortgage Comparison
Compare a 15-year and a 30-year mortgage side-by-side — payments, total interest, real amortization, and the hidden opportunity-cost math of investing the payment difference.
- 30yr Fixed6.51%
- 15yr Fixed5.84%
- 5/1 ARM6.47%
- 2yr Fixed5.68%
- 5yr Fixed5.63%
- Tracker3.96%
- Variable6.20%
- 2yr Fixed5.90%
- 5yr Fixed5.54%
- Variable5.95%
Rates shown are national averages for reference only. Actual rates vary by lender, credit score, and LTV. US 30/15-yr figures auto-refresh daily from the Freddie Mac PMMS public dataset.
Inputs
How it works
We compute the standard amortizing payment for each term and rate, then simulate both schedules month-by-month for the full 30 years and track:
- 15-yr path: loan is paid off at year 15, then the freed-up 15-yr payment is invested for another 15 years.
- 30-yr path: pay the lower 30-yr payment, and invest the monthly difference for the first 15 years, then let it grow for 15 more.
At year 30 both paths are debt-free — the winner is whichever ends with more invested wealth. Total interest still matters (it's a guaranteed saving), but this shows the full picture.
Frequently asked questions
Why is the 15-year rate lower?
Shorter loans carry less duration risk, so lenders typically price them 0.5–0.75% below 30-year rates.
Is a 15-year always better?
It saves enormous interest but demands a much bigger payment. If that crowds out emergency savings, 401(k) match, or IRA contributions, the 30-year is usually the smarter overall play.
Can I mimic a 15-year on a 30-year loan?
Yes — pay extra principal each month equal to (15-yr − 30-yr payment) and you'll match the 15-yr payoff while keeping the flexibility to drop back to the lower required payment.
What does 'invest the difference' assume?
That every month you pay the 30-yr's lower payment and invest the difference at your assumed return. This is only a real advantage if you'll actually invest it consistently.
Do 15-year loans have prepayment penalties?
Almost never on modern conforming loans — but always confirm with your specific lender.
Which term is most popular in the US?
30-year fixed dominates (~85%+ of purchase originations) because it minimizes the required monthly payment.