15 vs 30 Year Mortgage Calculator — Payment & Interest Comparison
Comparing 15-year and 30-year fixed mortgages shows the tradeoff between monthly payment and total interest. On a $400,000 home with 20% down at 5.75% (15-year) vs 6.5% (30-year), the 15-year payment is roughly $700/month higher but saves over $150,000 in lifetime interest. Enter your price, down payment, and both rates to compare.
15-Year Fixed
$3,157
Interest: $158,316
30-Year Fixed
$2,523
Interest: $408,142
- Monthly payment difference
- $635 more for 15-year
- Interest saved with 15-year
- $249,826
15-Year vs 30-Year Comparison
| Metric | 15-Year Fixed | 30-Year Fixed |
|---|---|---|
| Principal & interest | $2,657 | $2,023 |
| Total monthly (with tax & insurance) | $3,157 | $2,523 |
| Total interest | $158,316 | $408,142 |
| Total paid | $478,316 | $728,142 |
Methodology and limitations
Last reviewed:
Methodology
Compares 15-year and 30-year fixed PITI using separate rate inputs.
Limitations
Does not model ARM, IO, or extra-payment acceleration.
Official sources
How to Use the 15 vs 30 Year Mortgage Calculator — Payment & Interest Comparison
Comparing 15-year and 30-year fixed mortgages shows the tradeoff between monthly payment and total interest. On a $400,000 home with 20% down at 5.75% (15-year) vs 6.5% (30-year), the 15-year payment is roughly $700/month higher but saves over $150,000 in lifetime interest. Enter your price, down payment, and both rates to compare.
Method used
Runs side-by-side 15-year and 30-year fixed mortgage calculations with separate rates.
Practical example
Example: $400,000 home, 5.75% vs 6.5% — compare monthly PITI and total interest.
What this includes
- Shows payment difference and interest saved on 15-year.
- Includes tax and insurance.
What this excludes
- Does not model extra payments.
Frequently Asked Questions
Should I choose a 15-year or 30-year mortgage?
A 15-year mortgage builds equity faster and costs far less interest but requires higher monthly payments. A 30-year mortgage maximizes cash flow and affordability. Choose 15-year if you can comfortably afford the payment and want to be debt-free sooner. Choose 30-year if you need lower payments or prefer investing the difference — compare exact numbers here.
How much interest does a 30-year mortgage cost?
Total interest depends on loan amount, rate, and whether you make extra payments. Long terms can double or triple interest versus 15-year loans at similar rates. This calculator shows total interest for both terms side by side using your entered rates. Even a 0.5% rate discount on 15-year loans amplifies savings.
Are 15-year mortgage rates lower?
Yes. Lenders typically price 15-year fixed rates 0.5% to 0.75% below 30-year fixed because the shorter term is less risky. Enter separate rates for each term to reflect current market spreads. Freddie Mac PMMS publishes average spreads weekly — use lender quotes for your scenario.
Can I pay a 30-year loan like a 15-year?
Yes. Making extra principal payments on a 30-year loan can mimic a shorter payoff without locking in the higher required payment. You retain flexibility to reduce extras if income drops. Compare voluntary acceleration with the mortgage payoff calculator versus committing to a 15-year note here.
What is the monthly payment difference?
Payment difference equals the gap between 15-year and 30-year PITI at your home price, down payment, taxes, and insurance. This calculator displays both monthly totals and the dollar difference so you can judge whether the interest savings justify the higher 15-year payment in your budget.