Extra Principal Payment

Mortgage Payoff Calculator with Extra Principal Payment

Every extra dollar you pay goes directly to your principal — reducing the balance that interest is calculated on. Even small consistent extra payments can save tens of thousands of dollars over the life of your loan.

Loan Details

$
%
$

Year 1 = start from month 1. Year 5 = start at the beginning of year 5.

Extra Payment Strategy

Pay off9 yr 5 mo soonerWith $300/mo extra, you save $144,839 in interest.

Total Interest (Standard)

$404,079

Total Interest (With Extra)

$259,240

Standard Payoff Time

30 yr 1 mo

New Payoff Time

20 yr 8 mo

Balance Over Time

Standard pace
With extra payment

Estimates based on your inputs. Actual results may vary. Terms →

How much faster with different extra amounts?

Here’s how your payoff timeline changes as you increase your monthly extra payment.

Extra/moTime savedInterest saved
$100 4 yr 2 mo$65,914
$200 7 yr 2 mo$111,252
$300 (Your scenario)9 yr 5 mo$144,839
$500 12 yr 8 mo$191,923

*Based on your inputs: $300,000 at 6.8%

Frequently asked questions

What to calculate next

How extra principal payments work

When you make your regular mortgage payment, most of it goes to interest — especially early on.

Any EXTRA amount above your required payment goes 100% to principal.

This reduces your balance, which reduces next month's interest charge, which means more of your regular payment goes to principal too.

This compounding effect accelerates over time.

Monthly extra

Most consistent impact

Add a fixed amount every month.

Even $100/mo on a $300k loan saves ~$40k and cuts ~3.5 years off your term.

Set it and forget it.

Lump sum payment

Biggest one-time impact

Tax refund, bonus, or windfall.

A $10,000 lump sum early in your loan can save 2-3x that amount in interest.

Timing matters — earlier = more savings.

Bi-weekly payments

Easy automatic acceleration

Pay half your monthly payment every 2 weeks.

This creates 13 full payments per year instead of 12.

No budget change required — just a timing shift.

Saves ~4 years on a typical 30-year mortgage.

Estimates based on your inputs. Actual results may vary. Terms →