How to use
- Enter the original amount borrowed and the APR.
- Enter the full term in months, not years. A 3-year loan is 36.
- Enter how many scheduled payments have already been made.
- Press Calculate. The hero is the balance still owed.
How it's calculated
The scheduled payment is the standard amortizing payment for the full term. Balance after k payments = principal × (1+r)^k − payment × ((1+r)^k − 1) ÷ r, with r = APR ÷ 12.
Principal paid is the drop in the balance. Interest paid is the sum of the payments so far, minus that drop. A zero rate subtracts payment × k from the principal.
Worked example
A $10,000 loan at 6 percent for 36 months has a payment of about $304.22. After 12 payments the balance is about $6,864.06. Principal paid is about $3,135.94. Interest paid is about $514.69.
Assumptions
Every payment was the scheduled amount, on time, with no extra principal. The elapsed count cannot be longer than the term.
FAQ
What if I paid extra?
This form ignores extras. The extra-payment calculator is the one that adds a dollar amount on top of the bill.
Why months instead of years?
The balance formula counts payments. A year field would hide a loan that is not a whole number of years.
Can I enter zero payments made?
Yes. The balance should match the original principal, aside from rounding on the display.
Is the payment what I should send?
It is the payment the formula produces from the original term. If your statement shows a different payment, the rate, the term, or fees differ from what you typed.