Mortgage Payoff Calculator

See how extra monthly payments shorten your mortgage term and how much interest you save over the life of the loan.

Inputs

Loan balance

Interest rateAPR

Years remaining

Extra payment / moto principal

Results

Interest saved

$105,428.67

Time shortened

6y 7m

New payoff date

Mar 2050

Base monthly P&I

$2,022.62

Total interest (base)

$408,142.36

Total interest (extra)

$302,713.69

Principal & interest only — taxes, insurance, and PMI are not included. Assumes the extra amount is applied to principal each month with no prepayment penalty. Estimate for planning; confirm with your lender's amortization schedule.

Comprehensive Guide & Formulas

By CalcSuite Editorial TeamUpdated 14 June 20269 min read

Direct Summary / AI Overview

Extra payments & interest saved

Key Takeaways & Benchmarks

✓Extra principal payments reduce the balance that interest accrues on, shortening the loan and cutting total interest.
✓Even $100–$200 extra per month can shave years off a 30-year mortgage.
✓Early in the loan, most of your payment is interest — extra payments have the biggest impact then.
✓Check for prepayment penalties (rare on US residential mortgages) before accelerating payments.

What this calculator does

This tool shows what happens when you pay extra toward your mortgage principal each month: how much interest you save, how many years you shave off the loan, and your new payoff date — compared against your current amortization schedule.

How it works

1
Enter your loan balance
Your current remaining mortgage principal.
2
Enter rate and term
Your annual interest rate and years remaining.
3
Add an extra monthly payment
Any amount above the required payment, applied to principal.
4
Compare scenarios
Interest saved, years shortened, and new payoff date.

The formula

Monthly payment = P × r(1+r)^n ÷ ((1+r)^n − 1)

Each month: interest = balance × r; principal paid = payment − interest

Extra payments reduce the balance directly, so less interest accrues next month

Why extra payments are so powerful

▸Early in a 30-year loan, roughly 70–80% of each payment is interest — extra principal attacks the expensive part.
▸One extra payment per year (1/12 extra monthly) typically cuts ~4 years and tens of thousands in interest.
▸Biweekly payments (26 half-payments/year = 13 full payments) achieve the same effect automatically.
▸The higher your rate, the more each extra dollar saves — at 7%+, extra payments are a guaranteed high return.

Extra payments vs refinancing vs investing

Homeowners with extra cash face three main options, and the right choice depends on rates and goals. Paying extra on the mortgage is the simplest: it's a guaranteed return equal to your interest rate, it requires no paperwork, and it builds home equity you can tap later. At today's higher rates, that guaranteed return is genuinely attractive.

Refinancing replaces your loan with a new one at a lower rate. It makes sense when rates have dropped roughly 0.75–1% below yours and you'll stay in the home long enough to recover closing costs. Unlike extra payments, refinancing can also change your term — for example, moving from 30 to 15 years — which forces faster payoff but raises the required payment.

Investing the extra money instead is the mathematical favorite when mortgage rates are low. Over long periods, diversified stock market returns have historically exceeded typical mortgage rates — but with volatility and no guarantees. A balanced approach many planners suggest: pay enough extra to kill PMI or hit a comfortable equity level, then direct the rest to investments. To see what your paycheck actually leaves for either option, the Paycheck Calculator breaks down take-home pay.

Strategy	Best when	Trade-off
Extra principal payments	Rate above ~6%, want guaranteed return	Money is locked in home equity
Refinance	Rates dropped 0.75–1%+, staying 5+ years	Closing costs of 2–5% of loan
Invest instead	Rate below ~5%, long time horizon	Market risk, no guaranteed return
Biweekly payments	Paid biweekly already, want automation	Same as one extra payment/year

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Frequently asked questions

How do extra mortgage payments save money?+

Extra payments go directly to principal, which reduces the balance that interest accrues on. Because mortgage interest compounds monthly on the remaining balance, shrinking the balance early cuts total interest dramatically and shortens the loan term.

How much extra should I pay on my mortgage?+

Any amount helps — even $100–$200 extra per month can shave years off a 30-year loan. A common approach is one extra full payment per year (divide your monthly payment by 12 and add that each month), which typically cuts about 4 years off a 30-year mortgage.

Is it better to pay extra on my mortgage or invest?+

It depends on your rate and risk tolerance. Paying extra on a 7% mortgage is a guaranteed 7% return. Investing might earn more long-term but with risk. Many people do both. If your rate is under ~5%, investing the extra often wins mathematically over long periods.

Do extra payments go to principal automatically?+

Not always. Some lenders apply extra amounts to future payments or escrow unless you specify 'principal only.' Always confirm with your servicer that extra payments reduce principal, and check your statements.

Are there prepayment penalties on mortgages?+

Rarely on US residential mortgages — federal rules heavily restrict them, and most conventional loans have none. But always check your loan documents, especially for investment properties or non-QM loans.

Should I refinance instead of paying extra?+

Refinancing makes sense if you can drop your rate by roughly 0.75–1%+ and plan to stay long enough to recoup closing costs (typically 2–5% of the loan). Paying extra works within your current loan; refinancing changes the loan itself. You can also do both.

Does this calculator include taxes and insurance?+

No — it models principal and interest only. Property taxes, homeowner's insurance, and PMI are separate and don't change with extra principal payments (though PMI can drop off once you hit 20% equity).