Loan calculator

Calculate a monthly loan repayment schedule for annuity or declining-balance payments, see total interest and download the table as CSV.

How to calculate a loan payment

1
Enter amount, rate and term
Type the loan amount, the annual interest rate and how many months you will be paying it off.
2
Choose annuity or differentiated payments
Annuity keeps the monthly payment constant for the whole term; differentiated keeps the principal portion constant and lets the payment shrink month by month.
3
Review the schedule and download CSV
See the full month-by-month schedule with interest, principal and remaining balance, plus the total interest for the whole loan, and download the table as a CSV file.

Annuity vs. differentiated payments

An annuity loan charges the same payment every month: early on, most of it is interest and only a small slice reduces the principal, and that ratio flips as the balance shrinks. A differentiated loan repays an equal slice of principal every month, so interest, charged on a smaller and smaller balance, falls steadily and the total payment falls with it. For the same amount, rate and term, differentiated payments always add up to less total interest, at the cost of a larger payment in the first month than an equivalent annuity loan would ask for.

How the schedule is rounded

Every row is rounded to the cent as it is calculated, the same way a bank's ledger works, rather than only rounding the numbers shown on screen. Rounding hundreds of rows this way leaves a few cents of drift by the end of the term, and that drift is folded into the final row so the balance lands on exactly zero rather than a stray one-cent remainder.

Your numbers never leave this tab

The amount, rate and term you enter are read straight from the form and the entire schedule is calculated in JavaScript in your browser. Nothing is uploaded to a server; the CSV you download is built locally from the same numbers shown in the table.

Frequently asked questions

What is the difference between annuity and differentiated payments?

Annuity keeps the total monthly payment the same for the whole loan, with the interest-to-principal split shifting over time. Differentiated keeps the principal portion the same every month, so the payment, and the total interest charged, decreases steadily as the balance shrinks.

Which payment type is cheaper overall?

Differentiated payments always add up to less total interest for the same amount, rate and term, because interest is charged on a balance that shrinks faster. The trade-off is a bigger payment in the first month than the equivalent annuity payment.

How is the last row of the schedule calculated?

Rounding every row to the cent leaves a few cents of drift over a long schedule. Rather than letting the balance end on a stray fraction of a cent, that drift is added to the final row so the balance reaches exactly zero.

Can the schedule start on a date other than today?

Yes, set the start date field to any date. Every row's date is that start date plus one month per row, rolling short months forward correctly: the 31st of January plus one month lands on the last day of February.

Does this send my loan numbers to a server?

No. The amount, rate, term and every row of the schedule are calculated locally in your browser, and the CSV download is generated from the same in-browser data. Nothing is uploaded anywhere.

How do I convert the interest rate to a different currency's terms?

The interest rate itself does not change between currencies; only the amount does. Pick the currency your loan is actually denominated in from the currency field so the table shows the right symbol next to every figure.

What happens if I set the interest rate to 0%?

It is a fully valid input, not an error. Every formula on this page degrades cleanly to a plain division of the principal by the term, and the total interest shown is exactly zero.