Loan Calculator
Every amortizing loan — personal, student, business — follows the same math. Enter the amount, rate and term to get the monthly payment and total interest, then try an extra monthly payment to see how much sooner you could be debt-free and how much interest you would save.
Results
Formula
How to use this calculator
- Enter the amount, the annual rate and the term.
- Optionally add an extra monthly amount.
- Press Calculate and compare payoff time and interest with and without the extra.
Worked example
A $10,000 loan at 12% for 1 year.
- Monthly rate: 1%; payments: 12.
- Payment = 10,000 × 0.01 ÷ (1 − 1.01⁻¹²) ≈ $888.49.
- Total interest: 888.49 × 12 − 10,000 ≈ $661.86.
Result: Payments are about $888.49 a month and total interest is about $661.86.
Frequently asked questions
Why is so much of my early payment interest?
Interest is charged on the outstanding balance, which is largest at the start. As the balance falls, the interest share shrinks and more of each payment reduces principal — that is amortization.
Do extra payments always save the same amount?
No — extra payments save the most early in the loan, when the balance (and therefore the interest it generates) is highest.
What is the difference between APR and interest rate?
APR folds in certain fees and is meant for comparing loan offers. This calculator uses the plain interest rate; if your quote is an APR, the true payment may be slightly higher once fees are financed.
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