Mortgage Calculator

OVERPAYMENT CALCULATOR

See exactly how much interest you save and how early you become debt-free. Compare scenarios, view your full amortization schedule, and find the best overpayment strategy.

Your Mortgage

Currency

Loan Balance

Annual Interest Rate

Term (years)

Extra Payment

Pay Extra

Lump Sum (one-time)

Quick Scenario Picks

Your Overpayment Impact

Interest Saved

Years Early

Months Early

New Payoff

—

Without Overpayment

Total interest: $0

With Overpayment

Total interest: $0

Interest paid: $0 Interest saved: $0

Monthly Payment

Standard

With Overpayment

Extra Per Month

Amortization Schedule (accelerated payoff)

Year	Start Balance	Payment	Extra/Year	Interest	Principal	End Balance

Values rounded to nearest whole unit. Schedule shows accelerated payoff with extra payments applied.

Frequently Asked Questions

How does making extra mortgage payments save me money?

Extra payments reduce the principal balance faster, which means less interest accrues over the life of the loan. Even small additional payments can save thousands in interest and shave years off your mortgage term.

Is it better to make extra monthly payments or a one-time lump sum?

It depends on your cash flow. Extra monthly payments provide consistent long-term savings, while a lump sum gives an immediate principal reduction. Many borrowers use a combination of both strategies.

Can I overpay my mortgage at any time?

Some lenders charge prepayment penalties or limit how much extra you can pay each year. Check your mortgage terms before making additional payments. Many fixed-rate mortgages allow up to 20% extra per year without penalty.

What is the difference between weekly, monthly, and yearly overpayments?

Weekly payments reduce the principal more frequently, compounding the savings slightly faster than monthly payments. Yearly lump sums are easier to budget for but spread the benefit over a full year. Choose the frequency that fits your pay schedule.

How much should I overpay each month?

A common recommendation is 10-20% of your monthly payment. Even $50-100 extra per month can make a significant difference over a 25-30 year term. Use this calculator to find the amount that fits your budget and goals.

How to Use

Enter Your Loan Details

Type your loan balance, annual interest rate, and remaining term in years into the input fields above.

Choose Your Overpayment

Enter an extra payment amount and select the frequency (monthly, yearly, or one-time). Try scenario buttons for quick comparisons.

Review the Results

See how much interest you save, how early you pay off the loan, and the full year-by-year amortization schedule.

How to Calculate

The calculator uses the standard amortization formula. Each period, interest is calculated on the remaining balance: Interest = Balance × (Rate ÷ 12). The remainder of your payment goes toward the principal. Extra payments are applied directly to the principal, accelerating the payoff.

Results show the baseline (minimum payment) vs. with-overpayment scenario side by side, including total interest paid, payoff date, and years-and-months early.

About the Mortgage Overpayment Calculator

This free online Mortgage Overpayment Calculator helps homeowners and home buyers understand how extra payments affect their mortgage. All calculations run entirely in your browser — no data is sent to any server.

Supporting 16 currencies with locale-aware formatting, flexible payment frequencies (monthly, yearly, one-time), and one-time lump sums, this tool gives you a complete picture of your mortgage payoff strategy.

Related Tools