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Amortization Schedule with Extra Payments Lump Sum or Multiple Extra Payments


How much will I save by making extra principal payments?

The answer depends on :

  • The balance of the loan
  • The loan's interest rate
  • The payments remaining
  • And the additional amount paid

This amortization schedule will let you know what making extra payments will save you for your circumstances. The payment schedule supports:

  • one "lump-sum" extra payment
  • a specific number of extra payments
  • extra payments until you've paid off the loan
  • extra payments at a different frequency and on different dates than the "normal payment"


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An extra payment example

Assume you have a $400,000 at a 3.5% rate. Finding out how much you'll save if you make just an extra $100 payment until you've paid off the loan is easy. The amortization schedule will answer the question whether you've just taken out the loan or if the loan is one you've paid on for a while.

Set the calculator up this way:

  1. Loan Amount/Current Balance: 400,000.00
  2. Number of Payments (#): 360
  3. Annual Interest Rate: 3.25%
  4. Periodic Payment Amount: 1,740.83
  5. Extra Amount to Pay: 100.00
  6. Extra Payments Start: <as appropriate>
  7. Extra Payment Frequency: Monthly
  8. Number of Extra Pmts (#): Unknown


  • The calculator will calculate the regular periodic payment for you if you enter a "0". If you know the amount, you can enter it, and the payment schedule will use it.
  • If you want to calculate the interest, you'll save on an existing loan start by entering the loan's current balance and the number of remaining payments.
  • Assume you've received a large bonus, and you want to calculate the impact of making a single, lump-sum payment. To find out, change "Unknown" to "1" in step 8.
  • Like all calculators on this site, this one is very flexible. The frequency of additional payments does not need to be the same frequency as the scheduled payments. The extra payments also do not need to fall on the same date as the normal payments.

The amortization schedule

Study the payment schedule. Notice when there is an additional payment, the calculator uses 100% of the amount to reduce the balance. This is the case even when you make the extra payment between the scheduled payment dates. If you are making extra payments, you will want to use this calculator to verify that your lender applies the entire payment to principal. Some lenders do not do this

amortization schedule with $100 extra payment
Amortization schedule showing $100 extra payments.

The amortization summary and interest saved

The amortization schedule's summary header clearly shows you the amount of interest you will save by making extra payments.

amortization summary showing interest saved
Amortization summary showing over $22,000 in interest savings.

A note on terminology. Extra payments are not "extra." Therefore, this amortization calculator also uses the more appropriate term, prepaid principal, in the results area and schedule.

9 Comments on “Amortization Schedule With Extra Payments”

Join the conversation. Tell me what you think.
  • Pamela Jaquish Miller says:

    Me again. I have a mortgage and am using this amortization calculator to find out what the mortgagee owes to date. She has paid for many years but in 2020 she and her husband each made a payment on her account, bringing the balance down as I applied the extra mortgage payment to principal only. Now she is still making the double payments but she got a bonus at work and I am going to apply this to principal also. It will be $2040 extra. Where would I put that on this chart so that she would get credit for it? Thank you so much for your answers. I have learned everything about amortizing things from your charts and your help. Pam

    • What you want to do can’t be done with the calculator you are using.

      Please use this loan payoff calculator. If you use the suggested calculator to can enter payments for any amount that have been paid on any date.

      • Pam Jaquish Miller says:

        Thank you so much Karl. I always appreciate your help. I know you do this to help people, but is there any way I can send you money to repay you? Use it for Starbucks on the way to work? I would have to pay if I bought a program and it wouldn’t be as thorough as yours, nor could I ask it questions. If so, please email me at the address below and tell me if you have Paypal or Venmo. Thanks again for bailing me out, Pam

        • You’re welcome, Pam. I appreciate the offer of monetary support. It’s really not necessary. What would help me, even more, would be spreading the word about the site. If for example, you are on either LinkedIn or FB and you belong to a professional group that would benefit from these calculators, a mention from you would be worth its weight in gold. 🙂 Thanks for the offer.

  • HI Karl
    I really like your calculator. I have accelerated my weekly mortgage payment so the payment is different. So I adjusted number of weekly payments to get the right weekly payment amount. Its not perfect but it gives me a view of were I am going and more incentive to pay off the mortgage faster. Every month is an improvement. Thank you for this calculator.

  • How can I add fixed monthly extra payments to the amort. calculator?

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