Loan Calculator
Work out the monthly payment, total interest and total cost of any fixed-rate loan from amount, rate and term.
How it works
M = P × r ÷ (1 − (1 + r)^−n)
The standard amortization formula: P is the amount borrowed, r the monthly rate (annual ÷ 12 ÷ 100), n the number of monthly payments. Each payment covers that month’s interest first; the remainder reduces the balance, so the interest share shrinks every month.
Worked example
Borrow $20,000 at 8% for 5 years: r = 0.006667, n = 60. M = 20,000 × 0.006667 ÷ (1 − 1.006667⁻⁶⁰) ≈ $405.53. Total repaid ≈ $24,332, so interest ≈ $4,332.
Frequently asked questions
Does this work for personal, auto and student loans?
Yes — any fixed-rate, fixed-term loan that amortizes monthly uses this same math. Fees and variable rates are not included.
What if I pay extra each month?
Extra principal payments shorten the term and cut total interest. Even small extras early in the loan save a lot, because early balances are highest.
Is APR the same as interest rate?
APR includes certain fees on top of the interest rate, so it is usually slightly higher. For payment math, lenders use the note rate; APR is for comparing offers.
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This is an educational estimate, not financial advice. Lenders use their own rounding, fees and credit terms — confirm exact figures with your lender or a licensed advisor.