Finance calculators

Extra Payment Calculator

Updated Jul 13, 2026 By Jehan Wadia
Rate Formulas

Loan & Extra Payment Inputs

Base loan information
$
The starting principal of your loan ($1,000 – $3,000,000).
%
The nominal annual rate on the loan (0.01% – 15%).
The full length of the loan when it was originated (1 – 30 years).
Lets you start mid-loan. Must be ≤ the original term.

Extra payment configuration
$
Applied directly to principal each time it is due ($0 – $5,000).
Non-monthly payments apply only in the month they fall due.
Extra Payment Start
When extra payments begin.
Extra Payment End
"Ongoing" continues extra payments until payoff.

Results Summary

$0
Standard Monthly P&I (Baseline)
$0
New Monthly Payment Total
$0
Total Interest Saved
$0
Total Interest Without Extra Payments
Time Saved
New Projected Payoff Date
Side-by-Side Comparison
Comparison of totals with and without extra payments
Metric Without Extra Payments With Extra Payments
Total Payments Made
Total Interest Paid
Payoff Date
Compare Extra Payment Amounts
Interest saved:
Time saved:
Payoff:
Interest saved:
Time saved:
Payoff:
Interest saved:
Time saved:
Payoff:
Step-by-Step Solution

Visual Breakdown

Loan Balance Over Time
Cumulative Interest Paid Over Time
Amortization Schedule
Amortization schedule comparing the original loan with the extra-payment scenario

Introduction

Paying extra on your loan each month can save you a lot of money in interest and help you become debt-free years sooner. But how much can you actually save? This extra payment calculator shows you the answer in seconds. Just enter your loan amount, interest rate, loan term, and the extra amount you want to pay. The calculator does the rest.

You will see exactly how much interest you save, how many months or years you cut from your loan, and your new payoff date. It also builds a full amortization schedule so you can compare your original loan payments side by side with your extra payment plan. Charts and downloadable reports make it easy to see the difference at a glance.

This tool works for any type of fixed-rate loan, including mortgages, auto loans, personal loans, and student loans. You can choose to make extra payments monthly, quarterly, semi-annually, annually, or as a one-time lump sum. You can also set a start and end date for your extra payments if you only plan to pay extra for a limited time.

How to Use Our Extra Payment Calculator

Enter your loan details and extra payment plan below. The calculator will show you how much interest you save, how much time you cut off your loan, and your new payoff date.

Original Loan Amount: Type the full amount you borrowed when the loan started. This can be between $1,000 and $3,000,000.

Annual Interest Rate: Enter the yearly interest rate on your loan. You can find this on your loan statement. It must be between 0.01% and 15%.

Original Loan Term: Enter the total length of your loan in years. For example, type 30 for a 30-year mortgage.

Years Remaining on Loan: Enter how many years you have left to pay. This must be equal to or less than the original loan term.

Extra Payment Amount: Enter the extra money you want to put toward your loan principal each time. This can be between $0 and $5,000.

Extra Payment Frequency: Pick how often you want to make the extra payment. Choose monthly, quarterly, semi-annual, annual, or one-time payment.

Extra Payment Start: Select the month and year you want to begin making extra payments.

Extra Payment End: Select when you want to stop making extra payments. Choose "Ongoing" to keep paying extra until the loan is fully paid off.

Click the Calculate button to see your results. Click Reset to Defaults to start over with the original settings.

What Are Extra Payments on a Loan?

When you take out a loan, like a mortgage, you agree to pay it back over a set number of years. Each month, part of your payment goes toward interest (the fee the lender charges you) and part goes toward the principal (the actual amount you borrowed). Early in the loan, most of your payment goes to interest rather than paying down what you owe.

An extra payment is any money you pay on top of your normal monthly bill. This extra money goes straight to the principal. When you lower the principal faster, less interest builds up each month. Over time, this can save you thousands of dollars and help you pay off your loan years ahead of schedule.

How Extra Payments Save You Money

Interest on a loan is calculated based on your remaining balance. The higher the balance, the more interest you pay. When you make extra payments, your balance drops faster. A smaller balance means less interest each month, which means even more of your regular payment goes toward the principal. This creates a snowball effect that speeds up your payoff. If you have multiple debts, you might also explore the debt snowball or debt avalanche methods to accelerate your overall debt elimination.

For example, on a $300,000 mortgage at 6.5% interest over 30 years, just $100 extra per month can save you tens of thousands of dollars in interest and cut years off your loan. You can use our mortgage payoff calculator to see exactly when your home loan would be paid in full.

Ways to Make Extra Payments

There are several ways to apply extra money to your loan:

  • Monthly: Add a fixed amount to every payment. Even small amounts add up over time.
  • Biweekly: Another popular strategy is switching to biweekly payments, which results in one extra full payment per year.
  • Quarterly or annually: Make a larger extra payment every few months or once a year, such as when you get a bonus or tax refund.
  • One-time lump sum: Apply a single large payment, like an inheritance or savings, directly to your principal.

Things to Check Before Making Extra Payments

Before you start paying extra, make sure your lender applies the extra money to your principal and not toward future payments. Also check if your loan has a prepayment penalty, which is a fee some lenders charge for paying off your loan early. Most modern mortgages do not have this penalty, but it is worth confirming. If the penalty is significant, you might consider refinancing into a loan without one.

Extra payments work best when you start early in the life of your loan, because that is when your balance is highest and interest costs you the most. The sooner you begin, the more you save. To understand how interest compounds over time, try our compound interest calculator.


Formulas used

Monthly Interest Rate
r = \frac{\text{Annual Rate}}{12 \times 100}
Standard Monthly Payment (PMT)
PMT = P \cdot \frac{r(1+r)^{n}}{(1+r)^{n}-1}
Remaining Balance After k Payments
B_k = P(1+r)^{k} - PMT \cdot \frac{(1+r)^{k}-1}{r}
Monthly Interest Charge
I_m = B_{\text{current}} \times r
Principal Portion of Payment
\text{Principal} = PMT - I_m + \text{Extra Payment}
Total Interest Saved
\text{Saved} = I_{\text{base}} - I_{\text{extra}}

Frequently asked questions

Does the extra payment go toward interest or principal?

The extra payment goes straight to your principal (the amount you owe). It does not pay interest. By lowering your principal faster, you reduce the interest that builds up each month. This is how extra payments save you money.

What happens if I set the extra payment amount to $0?

If you set the extra payment to $0, the calculator shows your original loan schedule with no changes. This is useful if you just want to see your standard monthly payment, total interest, and payoff date without any extra payments.

What does Years Remaining mean and how is it different from the original loan term?

The original loan term is the full length of the loan when you first got it. Years remaining is how many years you still have left to pay. For example, if you took out a 30-year mortgage 5 years ago, your original term is 30 and your years remaining is 25. This lets the calculator figure out your current balance.

Can I use this calculator for a mortgage, car loan, or student loan?

Yes. This calculator works for any fixed-rate loan. That includes mortgages, auto loans, personal loans, and student loans. As long as your loan has a fixed interest rate and regular monthly payments, this tool will give you accurate results.

What is the difference between monthly and one-time extra payments?

Monthly means you add the extra amount to every single payment for as long as you choose. One-time means you make a single lump-sum payment on a specific date. Monthly extra payments usually save more interest over time because they reduce your balance continuously.

How does the Compare Extra Payment Amounts section work?

This section shows three scenarios side by side: half your extra payment amount, your chosen amount, and double your amount. For each one, it shows the interest saved, time saved, and new payoff date. This helps you decide how much extra to pay each month.

Why does the calculator show two columns in the amortization table?

The table shows your original schedule on the left and your extra payment schedule on the right. This lets you compare them side by side for each month or year. You can see how your balance, interest, and principal differ with and without extra payments.

What is the difference between the annual summary and monthly breakdown views?

The annual summary combines all 12 months of each year into one row. The monthly breakdown shows every single month as its own row. The annual view is easier to scan, while the monthly view gives you more detail.

Can I make extra payments for only part of my loan and then stop?

Yes. Use the Extra Payment Start and Extra Payment End fields to set a time window. The calculator will only apply extra payments during that period. After the end date, it goes back to your normal monthly payment.

Does this calculator account for taxes, insurance, or escrow?

No. This calculator only handles principal and interest (P&I). It does not include property taxes, homeowner's insurance, PMI, or escrow payments. Your actual total monthly payment to your lender may be higher than what the calculator shows.

How do I download my results?

Below each chart, you will find buttons to download the chart as a PNG image, SVG vector file, or CSV spreadsheet. Click the button for the format you want, and the file will download to your device.

What does the Step-by-Step Solution section show?

It walks you through the math behind your results. It shows how the monthly interest rate is calculated, how your standard payment is found, your current balance, and how the extra payments change your total interest and payoff timeline. This helps you understand exactly where the numbers come from.

Does this calculator work for adjustable-rate loans?

No. This tool is designed for fixed-rate loans only. If your loan has an adjustable or variable interest rate, the results will not be accurate because the rate can change over time.

What happens if my extra payment is more than my remaining balance?

The calculator is smart about this. If your extra payment would bring your balance below zero, it only applies enough to pay off the remaining balance. You will never overpay in the results.

How accurate are the results from this calculator?

The results are very accurate for fixed-rate loans based on the numbers you enter. However, your actual loan may have small differences due to rounding, payment processing dates, or fees. Always check with your lender before making changes to your payment plan.