Extra principal vs remaining interest

When Will My Mortgage Be Paid Off?

See how extra principal changes the remaining payoff date and interest on the current mortgage balance.

Your numbers

Mortgage payoff

How extra principal changes remaining interest and the payoff date.

Current principal$

Interest rate%

Remaining termmonths

Extra monthly principal$

Next payment date

Pay off sooner by

5 years 4 monthsEstimated payoff 2046-04-01

Scheduled P&I$1,610.75

Interest saved$57,646

Baseline remaining interest$233,226

How we got this

Scheduled P&I$1,610.75
Months saved5.3 years sooner64
Interest saved$57,646.33

What we assumed

The remaining payment is derived from the current balance, rate, and remaining term using the same amortization primitive as the Mortgage Payment Calculator.
Extra principal is added every month. Taxes, insurance, and escrow are not included.
This is not a lender recast, refinance analysis, or financial advice.

Technical details

Method mortgage-payoff-v1.0.0Data Manual inputs / fixed rules

Discrepancy in the numbers? You can click Report incorrect result below or email hello@costanswer.com with the Method and Data lines.

Guide

What extra principal does to a mortgage

CostAnswer editorialIndependent calculator publisher

Extra principal shortens the remaining schedule and cuts interest. The page uses the current balance, rate, and remaining term, then applies the extra amount you type. It does not decide whether you should prepay versus invest.

Interest saved is not a rate of return

Paying extra is a guaranteed reduction in interest at your mortgage rate, after any tax deduction you actually itemize. That is not automatically better than a retirement contribution or an emergency fund. The calculator only shows the loan math.

Questions about this calculator

How much interest do I save by paying extra each month?

Type the remaining balance, rate, remaining term, and extra principal. The page prints a new payoff date and interest saved versus the original remaining schedule.

Is extra principal better than refinancing?

They solve different problems. Extra principal keeps the same rate and cuts term. A refinance changes the rate and usually resets fees. Run both pages; neither is advice.

Terms used here

Extra principal: An amount applied to the balance on top of the required payment. It is not a fee to the lender.
Remaining term: Payments left, not the original 30 years.

Practical tips

Confirm with the servicer that extra amounts are applied to principal, not held as a cushion.

A one-time lump sum and a monthly extra are different inputs; do not mix them in one field.

Limits and caveats

Not investment advice. Prepaying a 3% mortgage while carrying 20% credit-card debt is a different decision than the math on this page.

Results are for information. They are not legal, tax, medical, or financial advice. How the math is maintained · Report a wrong figure.

How this is calculated

What the calculation includes, what it leaves out, and how it rounds.

With and without the extra. Your regular payment is worked out from the balance, rate and years left, the same way the mortgage payment calculator does it. The extra amount then goes to principal every month.
What it shows first. How many years and months sooner the loan is paid off, and the new payoff date if you enter a start date. The interest you save is shown underneath.
What is left out. Property tax, insurance, escrow, lender fees and one-off lump sums. Only a fixed extra amount each month is counted.

Calculation receipt

What each number here is

This answer is arithmetic on what you enter. No outside dataset is involved, so nothing here can go out of date.

Extra-payment savings fall out of the amortisation schedule.

Sources

Where this data comes from

Consumer Financial Protection BureauHow extra principal can shorten an amortizing mortgage.Official guidance ↗