Early Loan Payoff Calculator

An early loan payoff calculator is asked one thing — how much sooner, and how much cheaper — so this one opens with $200 a month of extra already entered and leads with months saved and interest saved rather than with the monthly payment.

Paid off May 1, 2029 after 32 payments

Monthly payment: $452.22
Payments: 32
Total interest: $2,390.53
Total paid: $20,390.53

31 payments of $652.22; the last is $171.71.

Against paying it to term

Months saved: 16
Interest saved: $1,315.84
Baseline payoff: September 1, 2030
Baseline interest: $3,706.37

If your lender counts the extra toward your next scheduled payment instead of the balance, this saving is $0.00: the loan is still paid off September 1, 2030 for $3,706.37 of interest, and all you buy is an earlier end to your own payments — month 34 of 48. Ask for it to be applied to principal only, and check the next statement.

Full amortization schedule — every payment

Every payment, from the first to the last. Total interest $2,390.53.
#	Date	Payment	Interest	Principal	Balance
1	2026-10-01	$652.22	$142.50	$509.72	$17,490.28
2	2026-11-01	$652.22	$138.46	$513.76	$16,976.52
3	2026-12-01	$652.22	$134.40	$517.82	$16,458.70
4	2027-01-01	$652.22	$130.30	$521.92	$15,936.78
5	2027-02-01	$652.22	$126.17	$526.05	$15,410.73
6	2027-03-01	$652.22	$122.00	$530.22	$14,880.51
7	2027-04-01	$652.22	$117.80	$534.42	$14,346.09
8	2027-05-01	$652.22	$113.57	$538.65	$13,807.44
9	2027-06-01	$652.22	$109.31	$542.91	$13,264.53
10	2027-07-01	$652.22	$105.01	$547.21	$12,717.32
11	2027-08-01	$652.22	$100.68	$551.54	$12,165.78
12	2027-09-01	$652.22	$96.31	$555.91	$11,609.87
13	2027-10-01	$652.22	$91.91	$560.31	$11,049.56
14	2027-11-01	$652.22	$87.48	$564.74	$10,484.82
15	2027-12-01	$652.22	$83.00	$569.22	$9,915.60
16	2028-01-01	$652.22	$78.50	$573.72	$9,341.88
17	2028-02-01	$652.22	$73.96	$578.26	$8,763.62
18	2028-03-01	$652.22	$69.38	$582.84	$8,180.78
19	2028-04-01	$652.22	$64.76	$587.46	$7,593.32
20	2028-05-01	$652.22	$60.11	$592.11	$7,001.21
21	2028-06-01	$652.22	$55.43	$596.79	$6,404.42
22	2028-07-01	$652.22	$50.70	$601.52	$5,802.90
23	2028-08-01	$652.22	$45.94	$606.28	$5,196.62
24	2028-09-01	$652.22	$41.14	$611.08	$4,585.54
25	2028-10-01	$652.22	$36.30	$615.92	$3,969.62
26	2028-11-01	$652.22	$31.43	$620.79	$3,348.83
27	2028-12-01	$652.22	$26.51	$625.71	$2,723.12
28	2029-01-01	$652.22	$21.56	$630.66	$2,092.46
29	2029-02-01	$652.22	$16.57	$635.65	$1,456.81
30	2029-03-01	$652.22	$11.53	$640.69	$816.12
31	2029-04-01	$652.22	$6.46	$645.76	$170.36
32	2029-05-01	$171.71	$1.35	$170.36	$0.00

What this page tells you

Paying a loan off early is a trade that can be priced exactly. A dollar paid ahead of schedule stops accruing interest for the entire remaining life of the loan, which means the value of an extra payment depends less on its size than on how early it lands. Two figures price it: the number of months the loan ends sooner, and the interest that never accrues. Both are differences between two complete schedules — the loan as written, and the same loan with the extra in it — and neither can be read off a payment.

This page runs both schedules in whole cents and shows every row of the second one. It loads with $18,000 at 9.500% over 48 months and $200 a month extra, because an early payoff question opening on a bare payment makes the reader do the comparison twice. Change the balance, the rate, the term or the extra and both figures move with it.

None of this is an argument for paying early. The saving is one side of a decision whose other side is a prepayment penalty if the loan carries one, and whatever else the money would otherwise do. The page computes the side it can compute to the cent, and names the parts it cannot.

How to read the result

Every dollar above the scheduled payment is treated here as reducing the balance on the day it is paid. That is one of two things a lender can do with it. The other is to count it toward your next scheduled payment, which moves the due date forward and leaves the balance where it was — and the saving below is then not smaller, it is zero. The standard mortgage contract lets the lender choose; on a federal student loan choosing for you is the default. Send it as a principal-only payment, in writing, and check the next statement.

Months saved and interest saved are measured against the same loan paid to term. The baseline is this balance, this rate and this scheduled payment — $452.22 on the default — run monthly for all 48 rows with nothing extra. The extra payment changes what is due each month and nothing else: not the rate, not the scheduled payment, not the baseline it is compared against.

The payoff date is the date of the last row of the schedule. With no extra, row 48 falls on 1 September 2030 and that is also the end of the stated term. With $200 a month the schedule stops at row 32, on 1 May 2029, and the sixteen months between those two dates are the answer to the question the page is named for.

An extra payment shortens the schedule; it does not lower the payment. $452.22 stays $452.22 and the loan simply ends sixteen rows early. Some lenders will re-amortize a loan after a large principal reduction, which lowers the payment and leaves the term where it was — the opposite outcome from the same money, and not what this page models.

The saving is not proportional to the extra, and it is not proportional to the total either. Timing does most of the work. On the default loan, $2,000 paid once with payment 12 saves $606.55; the same $2,000 paid as $200 with each of the first ten payments saves $741.35 and clears the loan a month sooner. Identical money, $134.80 apart, because the average dollar of the second arrives with payment 5.5 instead of payment 12.

Total interest comes from the schedule, and the final payment is where the two disagree. Multiplying the scheduled payment by 48 and subtracting the balance gives $3,706.56; the sum of the interest column is $3,706.37. The 19-cent gap is the smaller final payment, $452.03 against $452.22, and the schedule is the one that is right. With $200 a month running, the final payment is $171.71 — the last row only has to clear what is left.

The formula

M = \frac{P \cdot r}{1 - (1 + r)^{-n}}

M = \frac{P}{n} \qquad (r = 0)

i_k = \operatorname{round}\left(b_{k-1} \cdot r\right)

M: the scheduled payment, rounded up to the next cent
P: the balance at the start, in cents
r: the periodic rate — the APR divided by 100 and by 12
n: the term, in months
bₖ₋₁: the balance before payment k
iₖ: the interest charged in period k, rounded half-up to the cent

The payment is rounded up so the schedule cannot run past the term. Rounding to the nearest cent instead leaves a stray final payment of a few dollars on a long loan.

The payoff date comes from running the schedule, not from the formula. The two agree on ordinary loans and can differ by several months when the payment barely exceeds the interest.

The rounding rule, the final-payment adjustment and the published test vectors are all on the methodology page.

A worked example

A worked example: $18,000 at 9.5% over four years, three ways

Take $18,000 at 9.500% APR over 48 months. The monthly rate is 9.5 ÷ 100 ÷ 12 = 0.0079166667. Raising 1.0079166667 to the power of −48 gives 0.6848854197, so the denominator of the payment formula is 1 − 0.6848854197 = 0.3151145803. The numerator is 18,000 × 0.0079166667 = 142.50. Dividing gives $452.216460, which rounds up to a scheduled payment of $452.22. The first month accrues $142.50 of interest, so $309.72 reduces the balance to $17,690.28; the second accrues 17,690.28 × 0.0079166667 = 140.0480, rounded half-up to $140.05, and the balance falls to $17,378.11. Row 48 opens on $448.48, accrues $3.55, and the last payment is $452.03. That baseline costs $3,706.37 in interest and finishes on 1 September 2030.

Now add $200 a month. Every payment becomes $652.22, the first month still accrues $142.50 but $509.72 goes to principal instead of $309.72, and the balance after one row is $17,490.28 rather than $17,690.28. The schedule stops at row 32 — 1 May 2029, sixteen months early — with $2,390.53 of interest and a final payment of $171.71. The saving is $1,315.84, and the total paid over the life of the loan falls from $21,706.37 to $20,390.53. The closed form agrees on the count: −ln(1 − 0.0079166667 × 18,000 ÷ 652.22) ÷ ln(1.0079166667) = 31.2625, which rounds up to 32.

Against that, a single $2,000 with payment 12 and nothing else. Rows 1 to 11 are the baseline rows, so row 12 opens on $14,454.97 and accrues $114.44. The amount due is 452.22 + 2,000 = $2,452.22, of which $2,337.78 goes to principal, and the balance drops to $12,117.19 in one month. From there the schedule runs on the ordinary $452.22 and clears on row 43 — 1 April 2030, five months early — with $3,099.82 of interest. The saving is $606.55.

The comparison worth making is the third one. Pay that same $2,000 as $200 with each of the first ten payments and the loan clears on row 42, on 1 March 2030, with $2,965.02 of interest: six months early and $741.35 saved. The same $2,000 is worth $134.80 more spread across payments 1 to 10 than paid in full with payment 12, because the average dollar of it arrives with payment 5.5. Size decides how much principal disappears; timing decides how long each dollar of it was going to be charged interest, and on a 48-month loan the second effect is the larger one.

Scheduled payment: $452.22
Baseline: 48 payments, $3,706.37 interest, last payment $452.03
Baseline payoff date (from 1 October 2026): 1 September 2030
With $200 extra each month: 32 payments, $2,390.53 interest, last payment $171.71
Saved by $200 a month: 16 months and $1,315.84 — paid off 1 May 2029
With $2,000 once, at payment 12: 43 payments, $3,099.82 interest
Saved by the one-off: 5 months and $606.55 — paid off 1 April 2030
With the same $2,000 as $200 across payments 1–10: 42 payments, $2,965.02 interest
Saved by spreading it: 6 months and $741.35 — paid off 1 March 2030

Every figure here is derived from the formula above and checked to the cent against vector V2 / V8 form, derived from §1–§4 in the published test vectors — not read back off this page.

What this does not model

A surplus paid on a loan that is behind does not reduce the balance — it cures the arrears first, and only what is left after that reaches principal. Every schedule here assumes the loan is current and that each payment arrives on its scheduled date.
Prepayment penalties are not modelled. If the loan charges one for early payoff, the interest saved shown here is the figure before that charge, and the charge is the first thing to check against it. Fees, escrow, insurance and late charges are not modelled either.
Every extra is applied to principal in the period it is made. A lender that treats an unlabelled extra as an advance on the next scheduled payment instead moves the due date forward and saves nothing; that outcome is a different schedule from this one.
Interest is simple interest on the outstanding balance, charged once per period. There is no daily accrual and no compounding within a period, and every payment is assumed to arrive on its scheduled date.
The rate is fixed for the life of the loan. Variable and adjustable rates are not modelled, and neither are income-driven or forgiveness-based repayment plans.
Nothing you type is transmitted. The calculation runs in your browser, nothing is stored between visits, and the only thing that ever leaves it is the link you choose to copy.

When to use a different page

One loan or several, fixed payment or revolving — that is the real question behind this family of calculators, and it decides which page answers yours.

Loan payoff

The same engine, opened from the other end. The homepage starts from the loan as written — what the payment is, what it costs, when it ends — and treats the extra payment as the next question rather than the first one.

Extra payment

For when the extra is the fixed quantity and the loan is the variable: how far $100, $200 or $500 a month goes, sized against a balance rather than the other way round.

Mortgage payoff

Thirty years instead of four, where the same $200 a month is worth $103,446.46 rather than $1,315.84. That page also puts the bi-weekly schedule and dated lump sums in front, both of which matter more over a long term.

Debt payoff planner

Several balances and one monthly budget. Paying one loan early is arithmetic; deciding which of four to pay early is an ordering problem, and the planner rolls each freed payment into the next debt as it closes.

Questions people ask

How does an early payoff calculator work?

It builds two amortization schedules from the same balance, rate and scheduled payment. One runs to the end of the term with nothing extra; the other adds whatever extra is entered to the amount due each month. The difference in row counts is the months saved and the difference in the interest columns is the interest saved, both taken from the schedules rather than from a formula.

How much interest do I save by paying off a loan early?

It depends on the rate, on how much earlier the loan ends, and above all on when the extra money arrives. On $18,000 at 9.5% over 48 months, $200 a month cuts the term from 48 payments to 32 and the interest from $3,706.37 to $2,390.53 — sixteen months and $1,315.84. Halving the extra does not halve the saving, so the figure has to be computed rather than scaled.

Is it better to pay a lump sum once or a little extra every month?

Whichever gets the money onto the principal earlier, which is not always the lump sum. On the example above, $2,000 paid with payment 12 saves $606.55, while the same $2,000 paid as $200 across the first ten payments saves $741.35 and ends the loan a month sooner. If the lump sum is available now and the monthly extra is not, the lump sum wins on the same logic.

Does paying extra on a loan lower the monthly payment or shorten the term?

In this model it shortens the term. The scheduled payment stays at whatever the original loan set, and the schedule simply runs out of rows earlier. Re-amortizing after a large principal reduction — lowering the payment and keeping the original end date — is the other possible outcome, and it is not what the figures on this page describe.

Is it worth paying a loan off early?

That depends on the rate, on whether the loan carries a prepayment penalty, and on what the same money would do elsewhere. This page answers one part of it precisely: exactly how many months and exactly how many dollars the extra payment is worth against this loan. It does not know the rest of the picture and does not guess at it.