Loan Payment Example — How Monthly Payments Are Calculated
Understanding how loan payments are calculated helps you compare offers, plan your budget, and avoid overpaying. See real examples for mortgages, car loans, and personal loans.
The Loan Payment Formula
M = P × [r(1+r)ⁿ] ÷ [(1+r)ⁿ − 1]
M
Monthly payment
P
Principal (loan amount)
r
Monthly interest rate (annual ÷ 12)
n
Total number of payments
Real Loan Payment Examples
30-Year Mortgage — $350,000
Principal: $350,000
Annual Rate: 6.5% → Monthly rate: 0.5417%
Term: 360 months (30 years)
Monthly Payment: $2,212.24
Total Paid: $796,406 | Total Interest: $446,406
Over 30 years, you pay more in interest than the original loan amount. A 15-year mortgage at the same rate would cost $3,051/month but save $200,000+ in interest.
Car Loan — $28,000 at 5 Years
Principal: $28,000
Annual Rate: 7.2% → Monthly rate: 0.6%
Term: 60 months
Monthly Payment: $556.11
Total Paid: $33,366 | Total Interest: $5,366
Car loans are shorter-term, so interest costs are more manageable. A larger down payment reduces both the monthly payment and total interest.
Personal Loan — $10,000 at 3 Years
Principal: $10,000
Annual Rate: 11% → Monthly rate: 0.917%
Term: 36 months
Monthly Payment: $327.39
Total Paid: $11,786 | Total Interest: $1,786
Personal loans typically have higher rates than secured loans. Improving your credit score before applying can significantly reduce the rate.
How Interest Rate Affects Monthly Payments
On a $200,000 loan over 30 years:
| Interest Rate | Monthly Payment | Total Interest |
|---|---|---|
| 4% | $954.83 | $143,739 |
| 5% | $1,073.64 | $186,511 |
| 6% | $1,199.10 | $231,676 |
| 7% | $1,330.60 | $279,017 |
| 8% | $1,467.53 | $328,310 |
A 1% difference in rate on a $200,000 mortgage costs roughly $40,000–$50,000 more over 30 years.
Frequently Asked Questions
What is amortization?
Amortization is the process of paying off a loan through regular payments. Early payments are mostly interest; later payments are mostly principal. An amortization schedule shows the exact breakdown for each payment.
Does making extra payments help?
Yes, significantly. Extra payments go directly to principal, reducing the loan balance faster and saving substantial interest over the life of the loan.
What is APR vs interest rate?
The interest rate is the base cost of borrowing. APR (Annual Percentage Rate) includes the interest rate plus fees, giving a more complete picture of the loan's true cost.
How does a down payment affect my loan?
A larger down payment reduces the principal, which lowers monthly payments and total interest paid. It can also help you avoid PMI (private mortgage insurance) on home loans.