Repayment Calculator
Enter a loan amount, annual interest rate, and term to instantly see your monthly repayment, total interest, and total repaid.
Example
A $20,000 loan at 6.5% annual interest over 5 years (60 months): the monthly rate is 0.065 / 12 = 0.0054167. Using M = P·r / (1 − (1 + r)^−n), the monthly repayment is $391.32. Over 60 payments you repay about $23,479.36 in total, of which roughly $3,479.36 is interest.
How it works
Uses the standard amortization formula M = P·r / (1 − (1 + r)^−n), where r is the monthly rate and n is the number of months. Total repaid is M × n and total interest is total repaid minus the principal.
Good to know
The Repayment Calculator turns three numbers — loan amount, annual interest rate, and term — into the figures that actually matter when you borrow: your fixed monthly payment, the total interest you'll pay, and the grand total you'll hand back over the life of the loan. It's built for anyone weighing a personal loan, car loan, or any fixed-rate, equal-installment debt who wants a fast, honest picture before signing or comparing offers.
Reach for it when you're shopping rates between lenders, deciding between a shorter or longer term, or sanity-checking a quote against the headline "monthly payment" a salesperson gives you. Because it lets you flip the term unit between years and months, it's handy for both multi-year loans and short consumer financing — just change one input and watch the payment and interest recalculate instantly.
To read the result, start with the monthly repayment, then look at the two-bar split below it: the longer the interest bar relative to principal, the more you're paying for the privilege of borrowing rather than paying down the debt itself. A high "total interest" figure usually points to a long term, a high rate, or both — so try shortening the term and note how the monthly payment rises but the total interest drops.
- The "number of payments" field is your reality check: it's term in months, so a 5-year loan shows 60 payments — useful for confirming you entered years versus months correctly.
One caveat worth keeping in mind: this is a principal-and-interest estimate only. Real loans often add origination fees, insurance, or a different compounding convention, and many lenders quote an APR that bundles those costs in — so your actual payment and total cost can be higher than the clean figure shown here.
Frequently asked questions
What happens if I enter a 0% interest rate?
With a 0% rate the calculator simply divides the loan amount by the number of payments, so total interest is zero and the monthly payment is the principal spread evenly across the term.
Does this include fees, insurance, or taxes?
No. It only reflects principal and interest under a fixed rate with equal monthly payments. Origination fees, insurance, and other charges would increase your actual total cost.
Is my data uploaded anywhere?
No — this calculator runs entirely in your browser; nothing is uploaded.
Is this financial advice?
No. These are educational estimates — consult a qualified financial professional before making decisions.
People also ask
What is the formula for calculating a monthly loan repayment?
The standard amortization formula is M = P·r / (1 − (1 + r)^−n), where P is the loan amount, r is the monthly interest rate (annual rate divided by 12), and n is the number of monthly payments. This calculator uses exactly that formula, falling back to simply dividing principal by the number of payments when the rate is 0%.
What is the difference between interest rate and APR on a loan?
The interest rate is the cost of borrowing the principal alone, while APR (annual percentage rate) also folds in certain fees and charges to reflect the broader yearly cost. This tool works from the interest rate, so a loan's true APR may be higher once fees are included.
Does a longer loan term lower my monthly payment?
Yes, spreading the same loan over more months reduces each monthly payment because the principal and interest are divided across more installments. However, a longer term usually increases the total interest paid over the life of the loan.
How is total interest on a loan calculated?
Total interest equals the total amount repaid minus the original principal. Total repaid is the monthly payment multiplied by the number of payments, so total interest = (M × n) − P.
Can I use this to estimate a car loan or personal loan payment?
Yes, it works for any fixed-rate loan with equal monthly payments, including car loans and personal loans. Just enter the loan amount, the annual rate, and the term, keeping in mind it excludes fees, taxes, and insurance.
Why does paying off a loan early reduce interest?
Interest accrues on the remaining balance over time, so reducing the balance sooner means less interest can accumulate on it. This calculator assumes the full scheduled term, so it does not model the savings from extra or early payments.
What does the principal versus interest bar mean?
The two bars show how your total repayments split between paying back the money you borrowed (principal) and the cost of borrowing it (interest). A larger interest portion signals a higher rate, a longer term, or both.
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