
3-32 TIME VALUE OF MONEY
v-1.1 v.05/13/94
p.01/14/00
As you can see from the table, the interest on the deposit at the end of
Year One is compounded for nine years, interest on the deposit at the
end of Year Two for eight years, and so forth. The deposit at the end
of Year Ten earns no interest. Thus, at the end of ten years, the total
future value of this annuity is $1,257.80.
Using a
financial
calculator
Most financial calculators can perform this type of calculation.
The basic idea is to input the interest rate, the number of payments
and the size of the payments, and push the future value key to
calculate. Many calculators allow you to specify how many
payments per year and whether the payment is made at the beginning
of the period (annuity due) or at the end of the period (ordinary
annuity).
Present Value of an Annuity
Discounting
annuity
payments
The calculation of the present value of an annuity is the reversal of
the compounding process for the future value. The idea is to discount
each individual payment from the time of its expected receipt to the
present. We can illustrate by building another table
to calculate the present value of the annuity in Figure 3.4: ten
payments of $100, made on December 31st of each year, discounted
at a rate of 5%.
Year Payment x PVIF = Present Value
10 $100 x 1/(1.05)
10
= 61.39
9 $100 x 1/(1.05)
9
= 64.46
8 $100 x 1/(1.05)
8
= 67.68
7 $100 x 1/(1.05)
7
= 71.07
6 $100 x 1/(1.05)
6
= 74.62
5 $100 x 1/(1.05)
5
= 78.35
4 $100 x 1/(1.05)
4
= 82.27
3 $100 x 1/(1.05)
3
= 86.39
2 $100 x 1/(1.05)
2
= 90.70
1 $100 x 1/(1.05)
1
= 95.24
PV = $772.17
Figure 3.5: Present Value of an Annuity