15 to 30 Year Mortgage Calculator
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Reviewed by Calculator Editorial Team
This mortgage calculator helps you compare 15-year and 30-year loan terms by calculating monthly payments, total interest, and amortization schedules. Whether you're a first-time homebuyer or considering refinancing, understanding these options can save you thousands over the life of your loan.
How to Use This Calculator
To calculate your mortgage payments:
- Enter your loan amount (principal)
- Select your interest rate (APR)
- Choose between 15 or 30 year terms
- Click "Calculate" to see your monthly payment and total interest
The calculator uses standard mortgage formulas to provide accurate results. You can also view an amortization chart showing how your loan balance decreases over time.
Mortgage Payment Formula
The monthly mortgage payment is calculated using the standard formula:
Mortgage Payment Formula
P = L × [r(1 + r)^n] / [(1 + r)^n - 1]
- P = Monthly payment
- L = Loan amount (principal)
- r = Monthly interest rate (APR/12/100)
- n = Number of payments (term × 12)
Where the annual percentage rate (APR) is the nominal interest rate, and the monthly rate is calculated by dividing the APR by 12 months and by 100 to convert from percentage to decimal.
15 vs 30 Year Mortgages
Comparing 15-year and 30-year mortgages helps you understand the trade-offs between lower monthly payments and higher total interest costs.
| Term | Monthly Payment | Total Interest | Total Cost |
|---|---|---|---|
| 15 years | Higher | Higher | Lower |
| 30 years | Lower | Lower | Higher |
For example, a $200,000 loan at 4% APR would have:
- 15-year term: $1,520/month, $120,000 total interest, $320,000 total cost
- 30-year term: $995/month, $100,000 total interest, $300,000 total cost
Worked Example
Example Calculation
Loan amount: $250,000
Interest rate: 3.5% APR
Term: 20 years
Monthly payment: $1,380.25
Total interest: $125,000
Total cost: $375,000
This example shows how a 20-year term falls between 15 and 30-year options, offering a balance between monthly payments and total interest costs.
Frequently Asked Questions
What is the difference between APR and APY?
APR (Annual Percentage Rate) is the simple annual interest rate, while APY (Annual Percentage Yield) includes compounding effects, making it slightly higher for the same rate.
How does mortgage insurance affect my payments?
Mortgage insurance (PMI) is typically required for loans with a down payment under 20%. It adds to your monthly payment until you reach 20% equity.
Can I pay extra toward my mortgage?
Yes, making extra payments can reduce your principal balance faster and lower your total interest costs. Consider bi-weekly payments or lump sums.
What happens if I can't make my mortgage payments?
Missing payments can lead to late fees, higher interest rates, and potential foreclosure. Contact your lender immediately if you're having financial difficulties.