Loan Amortization Schedule Calculator: Balance After Any Payment

This calculator picks one line of a loan’s amortization schedule: enter the amount, APR, term and a payment number, and see the balance left after that payment and how the payment divides between interest and principal. For the whole table, use the full amortization schedule.

Formula

Balance after k payments: B_k = P(1 + r)^k − M((1 + r)^k − 1) ÷ r, with M the level payment and r = APR ÷ 1200. Interest in payment k = B_k−1 × r; principal in payment k = M − interest.

Worked Example

$200,000 at 6% APR over 30 years; the 12th payment.

1. r = 0.005, n = 360, M = $1,199.10
2. B₁₁ = 200,000 × 1.005¹¹ − M × (1.005¹¹ − 1) ÷ 0.005, so interest in payment 12 = B₁₁ × 0.005 = $988.77
3. Principal in payment 12 = 1,199.10 − 988.77 = $210.33
4. Balance after payment 12 = $197,543.98

Assumptions

• Fixed interest rate for the whole term; payments of equal size at the end of each month.
• Interest compounds monthly at APR ÷ 12.
• No fees, taxes or insurance unless the calculator has a field for them.
• Amounts are not rounded to the cent each month; a lender’s schedule can differ by a few cents.

How to read the result

After one year of a 30-year loan only about 1.2% of the balance is repaid: early payments are mostly interest. The principal part grows every month.

Limits and common mistakes

• The payment number must not be larger than the number of payments (years × 12).
• Extra payments are not included here; use the extra payment calculator.

Frequently Asked Questions

How much do I still owe after a year on a $200,000, 6%, 30-year loan?

About $197,544.

Why is so little principal repaid early on?

Interest is charged on the full balance; only what is left of the payment reduces the principal.

When does principal exceed interest?

On this loan, from payment 223 (after about 18.5 years).

in p | Loan amount | $ | 200000 | 1 | 100000000
in apr | Interest rate (APR) | % | 6 | 0.01 | 100
in yrs | Loan term | years | 30 | 1 | 50
in k | Payment number | - | 12 | 1 | 600
out bal | Balance after payment k | $ | max(0, p * (1 + apr / 1200) ^ k - p * (apr / 1200) / (1 - (1 + apr / 1200) ^ -(yrs * 12)) * ((1 + apr / 1200) ^ k - 1) / (apr / 1200)) + 0 * sqrt(yrs * 12 - k) | 2
out pmt | Monthly payment | $ | p * (apr / 1200) / (1 - (1 + apr / 1200) ^ -(yrs * 12)) | 2
out ik | Interest in payment k | $ | (p * (1 + apr / 1200) ^ (k - 1) - pmt * ((1 + apr / 1200) ^ (k - 1) - 1) / (apr / 1200)) * apr / 1200 | 2
out pk | Principal in payment k | $ | pmt - ik | 2