How do extra payments change interest?

Extras reduce the outstanding balance earlier. Interest each period equals balance times periodic rate, so smaller balances mean less interest accrues, compounding savings over time.

Can I target a specific payoff date?

This version shows payoff results based on your extras. Increase the recurring extra and recalc until the payoff aligns with your goal date.

Do property taxes or insurance affect the schedule?

No. The amortization covers principal and interest only. Escrows for taxes or insurance are separate from the loan balance and not included.

Mortgage Payoff Calculator

Q: What is the difference between monthly and biweekly payments?

Monthly uses 12 periods per year while biweekly uses 26. With the same APR, biweekly applies interest more frequently and adds two extra half payments per year, shortening the payoff.

Q: Why is my final payment smaller?

The schedule auto-adjusts the last payment so the loan closes exactly at a zero balance after applying interest for that period and any extras.

Inputs

Loan amount

Annual rate (APR)

Term

years

Start month

If empty, uses the current month.

Payoff acceleration

Payment frequency

Extra payment each period

Extra payment once per year

Applied in month

One-time lump sum

Applied at period #

Counting from first payment.

Example scenarios

Click any row to quick‑fill the form and recompute.

Loan	APR	Term	Freq	Extra/period	Annual extra
$350,000	6.5%	30y	Monthly	$250	$1,000
$240,000	5.75%	20y	Biweekly	$0	$2,500
$500,000	7.2%	30y	Monthly	$600	$0

Results

Standard payment

—

Computed from inputs

Payoff date

—

Total interest

—

With selected extras

Interest saved vs baseline

—

#	Date	Payment	Extra	Interest	Principal	Balance

Formulas used

Periodic payment (when rate > 0): P = L · r / (1 − (1 + r)⁻ⁿ), where L = loan amount, r = periodic rate, n = number of periods.

Zero‑rate case: P = L / n.

Per‑period interest: I_t = B_t−1 · r. Principal: Principal_t = Payment_t − I_t. Balance update: B_t = max(B_t−1 − Principal_t − Extras_t, 0).

For monthly, r = APR / 12 and n = years × 12. For biweekly, r = APR / 26 and n = years × 26. Extras reduce balance immediately after interest is applied each period; the final payment auto‑adjusts to clear any remaining cents.

How to use this calculator

Enter loan amount, annual rate, term, and optional start month.
Choose payment frequency, then add any recurring extra per period, yearly lump month, or one‑time lump by period number.
Click Calculate to produce the amortization, payoff date, and savings vs a baseline with no extras.
Export the schedule to CSV or PDF. Use the chart to visualize balance decline for baseline and with extras.
Test scenarios using the example table to see how small changes affect interest and payoff time.

FAQs

Monthly uses 12 periods per year; biweekly uses 26. With the same APR, biweekly applies interest more frequently and adds two extra half‑payments per year, shortening the payoff.

Extras reduce the outstanding balance earlier. Because interest each period is balance × periodic rate, smaller balances mean less interest accrues, compounding the savings over time.

The schedule auto‑adjusts the last payment so the loan closes exactly at a zero balance after applying interest for that period and any extras.

This version shows payoff results based on your extras. To hit an exact date, increase the recurring extra and recalc until the payoff aligns with your goal.

No. The amortization here covers principal and interest only. Escrows for taxes or insurance are outside the loan balance and not included in the calculations.