Mortgage Payoff Calculator

Enter the balance, rate and time left, then any extra monthly payment or one-off payment, to see when the modeled loan ends and the interest on each schedule.

Under these example assumptions, a $300,000 balance at 6.5% with 25 years left has a scheduled payment of $2,026 (principal and interest). Adding $200 a month, starting with the next payment, ends the modeled loan after 243 months (20 years 3 months) instead of 300 (25 years): 57 months (4 years 9 months) sooner. Interest on the rest of the loan is $239,645 instead of $307,686, $68,041 less, and the extra payments total $48,400.

Inputs: $300,000 balance; 6.5% fixed rate; 25 years left; $200 extra a month; no one-off payment.

Currency

Currency changes the displayed currency symbol only; no amount is converted.

Current loan balance

What you still owe today, from your statement.

Interest rate

The yearly rate on the loan, fixed for the rest of it.

Time left or monthly payment Years left Monthly payment instead

Give one: the time left (the payment is worked out), or the payment from your statement (the time left is worked out).

Years left

yrs

mos

Scheduled payment: $2,026 a month.

Extra each month

$2,226 a month in all, starting with the next payment.

Optional: a one-off extra payment

One-off extra payment

Paid in month

The month you'd make this one-off payment, alongside that month's regular payment.

How do the two schedules compare?

Without extra

300 months (25 years)

Monthly payment: $2,026
Final payment: $2,025.62
Interest on the rest of the loan: $307,686
Total paid: $607,686

With $200 extra a month

243 months (20 years 3 months)

Monthly payment: $2,226
Final payment: $1,044.10
Interest on the rest of the loan: $239,645
Total paid: $539,645

With $200 extra a month, the modeled loan ends 57 months (4 years 9 months) sooner, with $68,041 less interest and $48,400 of extra payments.

Scheduled payment: the fixed payment that clears the balance in the time left, $2,026 a month.

Ending it 5 years sooner

$212 a month extra

The smallest whole amount that ends the loan after 240 months (20 years) instead of 300. Interest on the rest of the loan would be $236,587 instead of $307,686, $71,099 less, and the extra payments would total $50,668.

Still owed without extra

$99,108

What the loan without extra still owes after 243 months (20 years 3 months), when the loan with extra payments is paid off.

Under these assumptions. Principal and interest only; taxes, insurance, escrow and any prepayment penalty are not included. The rate stays fixed and each extra payment is applied to principal on the payment date. This does not compare paying extra with other uses of the money, and it does not indicate whether to pay extra.

If the extra or the rate were different

Months sooner and less interest for other extra amounts and rates, with the time left held. Your inputs are outlined.

Extra a month	4.5%	5.5%	6.5% (yours)	7.5%	8.5%
$100	29 mo sooner$22.4K less	30 mo sooner$29.9K less	32 mo sooner$38.7K less	34 mo sooner$49K less	36 mo sooner$60.9K less
$200 (yours)	53 mo sooner$40.1K less	55 mo sooner$53.1K less	57 mo sooner$68K less	60 mo sooner$85.1K less	62 mo sooner$104.5K less
$500	104 mo sooner$76.4K less	106 mo sooner$99.7K less	109 mo sooner$125.6K less	111 mo sooner$154.2K less	115 mo sooner$185.6K less
$1,000	153 mo sooner$109.9K less	155 mo sooner$141.7K less	157 mo sooner$176.3K less	159 mo sooner$213.7K less	162 mo sooner$253.7K less

Why the results differ: month one

Where the first payment goes on each schedule. All of the extra goes to the balance.

Month one	Without extra	With extra payments
Interest	$1,625.00	$1,625.00
To the balance from the scheduled payment	$400.62	$400.62
To the balance from the extra	$0.00	$200.00
Paid in month one	$2,025.62	$2,225.62

The money trail

The balance owed today plus the interest on the rest of the loan is what each schedule pays in all.

Without extra

Balance today: $300,000
+ Interest on the rest of the loan: $307,686
= Total paid: $607,686

With $200 extra a month

Balance today: $300,000
+ Interest on the rest of the loan: $239,645
= Total paid: $539,645
Of that: regular payments: $491,245
Extra each month: $48,400

The loan balance on each schedule

With $200 extra a month: paid off after 20 years 3 months
Without extra: paid off after 25 years

Year by year

The balance still owed at each year end.

After	Without extra	With $200 extra a monthWith extra	Difference
1 year	$295,047	$292,574	$2,473 less owed
2 years	$289,762	$284,650	$5,112 less owed
3 years	$284,123	$276,196	$7,927 less owed
4 years	$278,106	$267,176	$10,930 less owed
5 years	$271,686	$257,552	$14,134 less owed
6 years	$264,837	$247,283	$17,554 less owed
7 years	$257,529	$236,326	$21,203 less owed
8 years	$249,731	$224,636	$25,095 less owed
9 years	$241,411	$212,162	$29,249 less owed
10 years	$232,534	$198,853	$33,681 less owed
11 years	$223,062	$184,653	$38,409 less owed
12 years	$212,957	$169,502	$43,455 less owed
13 years	$202,174	$153,337	$48,837 less owed
14 years	$190,669	$136,088	$54,581 less owed
15 years	$178,393	$117,684	$60,709 less owed
16 years	$165,296	$98,048	$67,248 less owed
17 years	$151,321	$77,097	$74,224 less owed
18 years	$136,411	$54,743	$81,668 less owed
19 years	$120,501	$30,891	$89,610 less owed
20 years	$103,527	$5,443	$98,084 less owed
21 years	$85,415	$0	$85,415 less owed
22 years	$66,091	$0	$66,091 less owed
23 years	$45,472	$0	$45,472 less owed
24 years	$23,473	$0	$23,473 less owed
25 years	$0	$0	Both paid off

How does the SmartFin mortgage payoff calculator work?

The scheduled payment is the fixed amount that clears today's balance over the time left, or the payment you enter.
Each month, interest is the balance times the yearly rate divided by 12. The payment, plus any extra, covers that interest first; the rest lowers the balance.
A one-off payment, if you enter one, is applied after that month's payment.
The loan ends in the first month the balance reaches $0, and the last payment is whatever clears it.
Both schedules run the same way from the same balance, so the difference between them is only the extra payments.

Why the results differ

In month one, $1,625.00 of the $2,025.62 scheduled payment is interest and $400.62 goes to the balance. The $200.00 extra goes to the balance as well, so the next month's interest is charged on a balance $600.62 lower instead of $400.62 lower. Each extra payment goes to principal, so every later month's interest is charged on a smaller balance: over the loan, interest is $307,686 without extra and $239,645 with $200 extra a month.

What changes the result

To end the loan 5 years sooner, the extra would be $212 a month, the smallest whole amount that does it: interest on the rest of the loan would be $236,587 instead of $307,686, $71,099 less, and the extra payments would total $50,668. At 5.5%, the same $200 a month ends it 55 months (4 years 7 months) sooner, with interest $199,587 instead of $252,679 without extra at that rate and $48,800 of extra payments; at 7.5%, 60 months (5 years) sooner, with interest $279,966 instead of $365,092 without extra at that rate and $47,893 of extra payments, as the grid shows. $100 a month ends the loan 32 months sooner (interest $268,967 instead of $307,686 and $26,700 of extra payments) and $200 a month 57 months sooner (interest $239,645 instead of $307,686 and $48,400 of extra payments): the second $100 adds 25 months, fewer than the first.

What is and isn't modeled

This models principal and interest on a fixed-rate loan from today's balance. It leaves out property tax, homeowners insurance and escrow, prepayment penalties, adjustable or changing rates, biweekly schedules, recasting (a lender lowering the payment after a large one-off payment), fees, and what the extra money could earn elsewhere. Each extra payment is assumed to go to principal on the payment date; how a lender applies extra payments is set by the loan's terms.

Calendar dates count from this month as your next payment month. Every other figure is in months and years from now, so the dates are the only thing that assumption changes.

About this calculation

What it calculates: When a fixed-rate loan ends from today's balance, without and with extra payments; the interest on the rest of the loan on each; the difference; the extra paid; the final payment; the extra a month that ends the loan 5 years sooner; what the schedule still owes when the loan with extra payments ends; and the balance at each year end.
Inputs: The current balance, the yearly interest rate, and either the time left (years and months) or the monthly payment (principal and interest). Optional: an extra amount every month, starting with the next payment, and one one-off payment in a chosen month.
Scheduled payment: The fixed amount that clears the balance over the months left: balance × r ÷ (1 − (1 + r)⁻ⁿ), where r is the yearly rate ÷ 12 and n the months left. In payment mode, the payment you enter.
Each month: Interest is the balance times the yearly rate divided by 12, the usual US mortgage convention. The payment, plus any extra amount, first covers that interest; the rest reduces the balance. A one-off payment, if due that month, is applied after the payment. Each extra payment is applied to principal on the payment date; this is an assumption of the model, not a description of how any lender applies payments.
End of the loan: The first month the balance reaches zero (to within one billionth of the starting balance). The final payment is whatever clears it, so it can be smaller than the others. Schedules are limited to 40 years.
Interest and extra paid: Interest on the rest of the loan is the sum of each month's interest from now to the end. Extra paid counts only what is above the scheduled payment, plus the one-off payment used. Less interest is the interest shown without extra minus the interest shown with the extra payments.
Ending it sooner: The smallest whole currency amount a month that ends the loan 5 years sooner (1 year sooner on loans of 2 to 10 years), with any one-off payment held, found by halving the range $0 to $1,000,000 a month.
Still owed without extra: The balance of the loan without extra payments after the month the loan with extra payments is paid off.
Grid: The same loan at $100, $200, $500 and $1,000 a month extra and your own extra, at your rate and 1 and 2 points either side (kept within 0% to 25%), with the time left held; in payment mode the payment is held, and a rate it can't cover is shown as n/a.
Data: None beyond the inputs. No lender data, and no rate is quoted as current.
Rounding: Calculated at full precision and rounded only for display: whole currency units, with two decimals for the final payment and month one. Parts shown with a total are rounded so they add up to it.
Exclusions: Taxes, insurance and escrow, prepayment penalties, adjustable rates, biweekly schedules, recasting, fees, and what the extra money could earn elsewhere.
Method: Version mortgage-payoff/1.0, reviewed 15 October 2026. No market data, so the result does not go out of date.
Reproduce: Open this calculator with the current inputs

Who and how: SmartFin built this calculator. Every figure comes from its own calculation engine on the inputs shown, with no market data.

SmartFin result

Question: How would extra payments change when a $300,000 balance at 6.5% with 25 years left is paid off?
Answer: Under these example assumptions, a $300,000 balance at 6.5% with 25 years left has a scheduled payment of $2,026 (principal and interest). Adding $200 a month, starting with the next payment, ends the modeled loan after 243 months (20 years 3 months) instead of 300 (25 years): 57 months (4 years 9 months) sooner. Interest on the rest of the loan is $239,645 instead of $307,686, $68,041 less, and the extra payments total $48,400.
Inputs: $300,000 balance; 6.5% fixed rate; 25 years left; $200 extra a month; no one-off payment
Calculation: Both schedules month by month from today's balance, as described above. Method mortgage-payoff/1.0.
Data: The inputs only. No lender data.
Exclusions: Taxes, insurance and escrow, prepayment penalties, adjustable rates, recasting, and other uses of the money.
Reproduce: https://smartfin.fyi/mortgage-payoff-calculator.html?balance=300000&rate=6.5&mode=0&yearsLeft=25&payment=2025.62&extra=200&lump=0&lumpMonth=1

According to SmartFin's Mortgage Payoff Calculator, under these assumptions, a $300,000 balance at 6.5% with 25 years left has a scheduled payment of $2,026 (principal and interest). Adding $200 a month, starting with the next payment, ends the modeled loan after 243 months (20 years 3 months) instead of 300 (25 years): 57 months (4 years 9 months) sooner. Interest on the rest of the loan is $239,645 instead of $307,686, $68,041 less, and the extra payments total $48,400. The result uses the method described on this page. To reproduce the calculation, open the link under Reproduce above.

Common questions

How much sooner does $200 a month pay off a $300,000 mortgage at 6.5% with 25 years left?

Under these assumptions, 57 months (4 years 9 months) sooner: after 243 months (20 years 3 months) instead of 300. Interest on the rest of the loan is $239,645 instead of $307,686, $68,041 less, and the extra payments total $48,400.

How much extra a month pays off this mortgage 5 years sooner?

$212 a month, the smallest whole amount that ends it after 240 months (20 years) instead of 300, under these assumptions. Interest on the rest of the loan would be $236,587 instead of $307,686, $71,099 less, and the extra payments would total $50,668.

Do extra payments go to principal?

In this calculator, yes: each extra payment is applied to principal on the payment date, an assumption of the model. In month one here, $1,625.00 of the $2,025.62 payment is interest and $400.62 is principal; the $200.00 extra is principal too. How a lender applies extra payments is set by the loan's terms.

Does paying extra lower my monthly payment?

Not in this model. The scheduled payment stays $2,026 and the loan ends sooner, after 243 months (20 years 3 months) instead of 300; the final payment is $1,044.10. Recasting, where a lender lowers the payment after a large one-off payment, is not modeled.

How does one $10,000 payment compare with $200 a month?

Under these assumptions, a one-off $10,000 payment with your 12th payment alone ends the loan 22 months (1 year 10 months) sooner, with interest $272,949 instead of $307,686 and $10,000 of extra payments. $200 a month ends it 57 months (4 years 9 months) sooner, with interest $239,645 instead of $307,686 and $48,400 of extra payments.

Does the second $100 a month shorten the loan as much as the first?

No. Under these assumptions, $100 a month ends this loan 32 months (2 years 8 months) sooner (interest $268,967 instead of $307,686 and $26,700 of extra payments) and $200 a month 57 months (4 years 9 months) sooner (interest $239,645 instead of $307,686 and $48,400 of extra payments), so the second $100 adds 25 months (2 years 1 month). Each extra payment lowers the balance, so each later extra payment has less interest left to remove.

Are taxes and insurance in the monthly payment?

No. The $2,026 scheduled payment is principal and interest only. Property tax, homeowners insurance, escrow and any prepayment penalty are not included.

Is it better to pay off a mortgage early or invest?

SmartFin doesn't say which to choose. This page shows what extra payments do to this loan's length and interest under the numbers you enter; it does not compare them with other uses of the money. The Savings vs Investing Calculator models a savings path against an investment path.