Work out a loan payment
Put in the amount, the rate and how long you have. The payment and what it costs you over the term appear as you type.
How it works
A repayment loan is one arithmetic identity: a fixed monthly amount, chosen so the balance reaches zero on the final payment. Each month interest is charged on what you still owe, the payment covers that first, and whatever is left reduces the balance. That ordering explains why the early years feel like they achieve nothing.
Where the money goes early on
On a 30-year mortgage at 6 percent, the first payment is roughly three quarters interest. The split reverses slowly and does not reach even until well past the halfway point in time. Nothing is being withheld and no fee is hiding in there. Interest is rent on the outstanding balance, and early on that balance is nearly the whole loan.
The schedule below the answer shows the split for every month. It is worth reading once, because it makes the next paragraph obvious rather than surprising.
Why a small overpayment does so much
An extra payment made early removes principal that would otherwise have accrued interest for the entire remaining term. The saving is not the extra amount, it is the interest that amount would have generated for two or three hundred months. Overpaying at the start is therefore worth several times the same money at the end.
The reverse holds for extending a term. Stretching a loan lowers the monthly figure and raises the total, often by more than people expect, because the balance stays high for longer and interest is charged on the balance.
The rate here is nominal, not APR
This uses the nominal annual rate divided by twelve, which is how lenders quote and compute a monthly instalment. An APR folds fees and charges into a single comparison figure and will usually read slightly higher. If you are comparing two offers, compare their APRs; if you are checking a lender's payment figure, use the nominal rate, which is what this does.
Rounding is to the cent on every month, and the final payment absorbs whatever is left over so the balance lands exactly on zero. A schedule that ends at minus three cents is a schedule someone will not trust, and the arithmetic here is done in whole cents for that reason.
Questions
Does this match what my bank will quote?
The payment should agree to the cent for a straightforward repayment loan. Differences usually come from fees folded into the advance, a first period that is not exactly one month, or a lender rounding the payment up to the nearest whole unit of currency. Any of those shift the figure slightly without changing the method.
Is my loan amount or rate sent anywhere?
No. The arithmetic runs in this tab and the page makes no request while you type. What you enter here is not visible to us, and there is nothing to be visible.
What about an interest-only loan?
This models a repayment loan, where the balance falls to zero. An interest-only payment is the balance times the annual rate divided by twelve, and the balance never reduces, so the total cost is that figure times the number of months plus the original sum at the end.
Can I get the schedule as a spreadsheet?
Yes. The download beside the answer is a CSV of every month with the opening balance, the interest, the principal and the closing balance. It opens in Excel, Numbers and Sheets without conversion.