以下のガイドはまだ日本語に翻訳されていないため、英語で表示しています。計算機自体はすべて日本語に対応しています。
この計算機の使い方
- Enter the amount you want to borrow and select your currency.
- Enter the annual interest rate quoted by the lender (the nominal rate, not the APR if fees are separate).
- Set the loan term in years and, if needed, additional months.
- Optionally add an extra monthly payment to see how much sooner you would repay the loan.
計算式
Fixed-rate loans use the amortization formula. L is the amount borrowed, r is the monthly rate (annual rate ÷ 12) and n is the number of months. When the rate is 0%, the payment is simply L ÷ n.
Payment = L × r / (1 − (1 + r)^−n)
Total interest = Payment × n − L
Example
- Borrow $20,000 at 8% for 5 years: r = 0.08 ÷ 12 = 0.006667, n = 60.
- Payment = 20,000 × 0.006667 / (1 − 1.006667^−60) ≈ $405.53 per month.
- Total paid ≈ $24,331.80, so total interest ≈ $4,331.80.
よくある質問
What is the difference between interest rate and APR?
The interest rate is the cost of borrowing the principal. The APR also includes most fees, such as origination fees, expressed as a yearly rate. Use the APR calculator to convert fees into an APR.
How do extra payments affect a loan?
Extra payments are applied to principal, which reduces future interest and shortens the term. The calculator shows the interest you save compared with making only the regular payment.
Why is my lender's payment slightly different?
Lenders may round payments differently, count days instead of months, or add insurance or fees to the payment. Small differences of a few cents are normal.