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Currently the Amortization Schedule Calculator is the most popular financial calculator on this website. It calculates one of four unknowns or you can provide all the values. You are also in control of the loan and first payment dates. More below...»

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Related: Need to amortize a really big debt? US National Debt Calculator handles debts to $99 trillion. Amortize entire debt or your family's share of the debt (surprise!). Also, generic use for bond coupon schedules.

Important Note About Dates: This calculator allows irregular length first periods. That is, the calculator calculates the exact amount of interest due even when the initial period is shorter or longer than the other scheduled periods. This will produce interest charges that do not match other calculators. If you want to match other calculators then set the "Loan Date" and "1st Payment Date" so that they equal one full period as set in "Payment Frequency". Example: If the "Loan Date" is May 15th and the "Payment Frequency" is "Monthly", then the "1st Payment Date" should be set to June 15th, that is IF you want a conventional interest calculation. See the end of the "Help" text for some more details.

What is amortization? According to, "amortization means a debt is being paid off by a series of payments". When people search for an amortization calculator, they search for it using many different search phrases. If you are searching for any of these financial calculators, this calculator should meet your needs. If it doesn't, feel free to tell me what you need in the comment area below and there is a good chance I'll be able to make a recommendation.

Related: Don't over pay, don't under collect. If you need to track payments on the exact date they are paid (or missed) for whatever amount, then use the loan payoff calculator. For a step-by-step example see the payoff calculation tutorial.

This website has dozens of financial calculators that create various amortization schedules, payment schedules, withdrawal schedules and general cash flow schedules. This is a complete list of our free, online calculators. Feel free to surf!

Need More Features?

The loan calculator, mortgage calculator and
auto loan calculator have all recently been updated.

  • Supports setting dates - just like this calculator
  • User controls when and how odd day interest is due
  • Do "what-if" with extra payments
  • User can select last month for year end totals

584 thoughts on “amortization-schedule

  1. Hello Karl,
    I followed your lead and focused exclusively on the interest calculation.

    Again using the following data: Loan = $32,500; APR = 7.5%; Payments # = 8; Loan Date = 07/01/2018; First Payment Due: 08/01/2018; Payment Frequency: Monthly; Compounding: Weekly; Points: 0%; Amortization Method: Normal; Days per year: 360.

    Using these variables your calculator, interest on the first installment amounts to $208.34

    In this instance I used the standard textbook formula for compounding interest—> S = P*(1+R/N)^(N*T)-1
    S = value of principal and interest; P = original principal amount; R = annual percentage rate; N = number of years; T = number of compounding periods in 1 basis year. Data used is P = $32,500; R = 7.5%, N = 52 (weeks in year)
    I assume that for a term of 1 month (from 07/01/18 to 08/01/18), T = 0.083333333 or 1/12th of one year.

    Using these variables S = $32,703.61. After subtracting the principal ($32,500), the interest for 1 month will equal $203.61

    So I am stuck with a difference which I cannot explain from basic textbook mathematics.

    Hoping to hear from you.
    Kind regards,

    • Hi Mark, First, I guess I should have pointed it out in the prior reply that I do not provide support for the equations. My support is limited to two types of questions:

      1. What calculator do I need to use to accomplish "X"
      2. How do I use calculator "Y" to solve a problem

        But that said, your assumption about T is wrong if you want weekly compounding. That’s monthly compounding.

  2. Thanks Karl

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