Loan Calculator
CalculateWork out the monthly payment, total interest, and payoff date on any loan, and see how much an extra monthly payment saves. Includes a year-by-year amortization table.
Runs entirely in your browser. Nothing is uploaded.
Monthly payment
$489.15
Total interest
$4,349.22
Total repaid
$29,349.22
Payments
60
Payoff time
5y 0m
| Year | Interest | Principal | Balance |
|---|---|---|---|
| 1 | $1,496.23 | $4,373.62 | $20,626.38 |
| 2 | $1,203.32 | $4,666.53 | $15,959.86 |
| 3 | $890.79 | $4,979.05 | $10,980.81 |
| 4 | $557.34 | $5,312.51 | $5,668.30 |
| 5 | $201.55 | $5,668.30 | $0.00 |
Monthly payment & total interest
The monthly payment is the number lenders lead with, and the total interest is the number that actually matters. A small difference in rate or term barely moves the payment while changing what you repay over the life of the loan by thousands. This calculator shows both at once, adds a year-by-year breakdown of how much of each payment is interest rather than principal, and lets you test what an extra payment each month would do to the term.
How to calculate a loan payment
- 1
Enter the amount and rate
Put in what you are borrowing and the annual interest rate you have been quoted, not the APR if they differ.
- 2
Set the term
Enter the length in years. A longer term lowers the payment and raises the total interest.
- 3
Try an extra payment
Add an optional amount per month to see how many months earlier the loan clears and how much interest that avoids.
Good to know
- Uses the standard amortising formula: M = P · i(1+i)^n / ((1+i)^n − 1), with i as the monthly rate and n the number of payments.
- Early payments are mostly interest and late payments mostly principal, which is why overpaying early saves far more than overpaying later.
- Principal and interest only — origination fees, insurance, and add-ons your lender bundles into the financed amount are not included.
- If the payment does not cover the monthly interest, the balance would never reach zero, and the tool says so rather than showing a misleading figure.
What people use it for
- Comparing two loan offers on total cost rather than monthly payment
- Working out whether a shorter term is affordable before applying
- Seeing what rounding your payment up each month would actually save
Frequently asked questions
What formula does it use?+
The standard amortising-loan formula: M = P · i(1+i)^n / ((1+i)^n − 1), where P is the amount borrowed, i is the monthly interest rate, and n is the number of monthly payments.
How does the extra payment work?+
The balance is walked forward month by month, so an extra payment reduces the principal directly and shortens the term. The result shows how many months earlier the loan clears.
Does this include fees?+
No. It models principal and interest only. Origination fees, insurance, and any add-ons your lender bundles in are not included, so compare the APR you are quoted as well.
Why does my lender's number differ slightly?+
Lenders may use a different day-count convention, round payments to the cent differently, or add fees into the financed amount. Small differences are normal; large ones usually mean extra costs are included.
Is my data sent to a server?+
No. Calculating happens entirely in your browser using built-in web APIs. Nothing is uploaded, stored, or logged.
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