Basic Annuity Calculation
In this section, we will discuss the most
basic annuity calculation. This annuity calculation finds how
much the annuity owner would have accumulated in annuities
after so many years. This basic annuity calculation is very
useful. We use the annuity formula below to do the annuity
calculation. Once you understand how to do this annuity
calculation, you can memorize the annuity formula below so that
you can do the annuity calculation quickly in the future.
How to calculate the amount of
annuity?
Suppose you invest an amount of money
A in an annuity at the end of each of the
next n years. From this annuity, you earn a
rate of interest r throughout the period. The
question is how much will you have accumulated at the end of
nth year?

The annuity chart above illustrates how an
annuity works. The annuity owner deposits money
A into the annuity every year from year 0
to year n. We have an easy way of calculating
how much the owner would accumulate. The annuity calculation
assumes that:
-
the first payment is made at the end of the first
time period (year 0)
-
the last payment is made at the end of the last
time period (year n)
-
the amount A is constant each year
-
the amount of annuity accumulated, An, is the sum
all the annuity contributions grown at the rate of
interest r.
The annuity calculation
First use the formula for compound
interest:

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