Extra mortgage payment calculator

Estimate how recurring extra principal from payment one could change payoff timing and modeled interest. Your numbers stay on this device.

Your loan

Loan amount

Models a new fixed-rate schedule from payment one.

Annual note rate

Note rate, not APR.

Loan term

Extra principal each month

Maximum recurring amount paid after scheduled principal and interest until payoff.

Example estimate

Pay off 7 years 3 months sooner

$135,678.64 less interest

87 monthly payments avoided

Scheduled principal and interest: $2,334.95
Voluntary extra principal: $250.00
Planned regular payment: $2,584.95
Baseline payoff: 30 years
Estimated payoff with extra: 22 years 9 months
Baseline modeled interest: $480,583.13
With-extra modeled interest: $344,904.50
Estimated final payment: $1,797.24

Educational estimate only. This tool does not provide a loan offer, approval, qualification decision, payoff statement, servicing record, tax advice, legal advice, or individualized financial advice. Results depend on the assumptions entered and may differ from lender, servicer, insurer, tax authority, HOA, or closing documents.

Confirm payment application and any prepayment terms with your servicer. Excludes escrow, fees, skipped or late payments, daily-interest servicing, recasts, biweekly schedules, penalties and future rate changes.

Printing uses your browser’s print dialog. The copied link contains no entries or results.

Baseline versus extra payments

Compare the scheduled plan with the same loan plus recurring extra principal.

Modeled loan plan comparison
Scenario	Planned regular payment	Payoff time	Payments	Total modeled interest
Scheduled plan	$2,334.95	30 years	360	$480,583.13
With up to $250.00 extra each month until payoff	$2,584.95	22 years 9 months	273	$344,904.50
Difference	$250.00 more	7 years 3 months sooner	87 fewer	$135,678.64 less

First five years and payoff milestone

See how the modeled balance changes with and without recurring extra principal.

Ending balances under the scheduled and extra-payment plans
Point	Scheduled balance	Extra-payment balance	Difference
Year 1	$356,163.31	$353,068.73	$3,094.57
Year 2	$352,059.47	$345,654.85	$6,404.62
Year 3	$347,669.90	$337,724.76	$9,945.13
Year 4	$342,974.68	$329,242.52	$13,732.17
Year 5	$337,952.55	$320,169.67	$17,782.89
Estimated payoff (month 273)	$160,291.71	$0.00	$160,291.71

Assumptions and limitations

This tool creates a fixed-rate amortization schedule from payment one and assumes recurring extra principal of up to the entered amount reaches principal after each scheduled payment until payoff. It may not match an existing loan’s contractual payment after prior prepayments, modifications or recasts.

It does not model escrow, fees, daily-interest servicing, skipped payments, payment timing changes, biweekly plans or prepayment penalties.

Read the extra-payment methodology

How extra payments are modeled

The engine calculates one baseline fixed-rate schedule and a second schedule that applies recurring voluntary extra principal of up to the entered amount after each scheduled payment until payoff.

Interest saved is the difference between the two unrounded schedule totals. The last payment may be smaller than the regular planned amount.

Check the calculation and sources

Worked example

$100,000 loan 4.00% note rate 30 years

$100 recurring extra principal

Scheduled principal and interest: $477.42
Estimated payoff: 21 years 7 months
Months saved: 101
Modeled interest saved: $22,464.51

Illustration only—not a payoff quote or servicing ledger.

Review formulas and primary sources Read the corrections policy

Extra mortgage payment questions

Will this match my existing mortgage statement?

Not necessarily. This tool models a new schedule from payment one. Prior payments, recasts, servicing rules and contractual rounding can change an existing loan’s payment and payoff.

Is extra principal guaranteed to save this amount?

No. Confirm that your servicer permits extra payments and applies them to principal. Actual timing, fees and servicing practices can differ.

Why might the final payment be smaller?

The engine caps the last payment at the modeled balance and interest remaining, rather than assuming another full regular payment.