Section PF.11 – Payout Annuities


In the last section you learned about annuities. In an annuity, you start with nothing, put money into an account on a regular basis, and end up with money in your account. In this section, we will learn about a variation called a Payout Annuity. With a payout annuity, you start with money in the account, and pull money out of the account on a regular basis. Any remaining money in the account earns interest. After a fixed amount of time, the account will end up empty. Payout annuities are typically used after retirement. Perhaps you have saved $500,000.00 for retirement, and want to take money out of the account each month to live on. You want the money to last you 20 years. This is a payout annuity.

Payout Annuity Formula

P0 = [latex]\large{\frac{PMT(1~-~(1~+~\frac{r}{n})^{-nt})}{\frac{r}{n}}}[/latex]

P0 is the balance in the account at the beginning (starting amount, or principal).

PMT  is the regular withdrawal (the amount you take out each year, each month, etc.)

r is the annual interest rate (APR) in decimal form (Example: 5% = 0.05)

n is the number of compounding periods in one year.

t is the number of years we plan to take withdrawals

Like with annuities, the compounding frequency is not always explicitly given, but is determined by how often you take the withdrawals.

When do you use the Payout Annuity Formula?

Payout annuities assume that you take money from the account on a regular schedule (every month, year, quarter, etc.) and let the rest sit there earning interest.

Compound interest: One deposit/starting balance

Annuity: Repeated deposits.

Payout Annuity: Repeated withdrawals

Example 1
After retiring, you want to be able to take $1,000.00 every month for a total of 20 years from your retirement account. The account earns 6% interest. How much will you need in your account when you retire?

Putting this into the equation: P0 = [latex]\large{\frac{1,000(1~-~(1~+~\frac{0.06}{12})^{-12~\cdot~20})}{(\frac{0.06}{12})}}[/latex] = $139,580.77

Using TVM Solver:

N = 12*20
I% = 6
PV = This is what you are solving for.
PMT = 1000
FV = 0
P/Y = 12
C/Y = 12
PMT: END

Once all of the given parameters are entered in, solve for PV. PV = -139,580.7717

You will need $139,580.78 in the account by the time you retire.

Example 2
You know you will have $500,000.00 in your account when you retire. You want to be able to take annual withdrawals from the account for a total of 30 years. Your retirement account earns 8% interest. How much will you be able to withdraw each year?

Putting this into the equation: 500,000 = [latex]\large{\frac{PMT(1~-~(1~+~\frac{0.08}{1})^{-1~\cdot~30})}{(\frac{0.08}{1})}}[/latex]

Solve for PMT to get PMT = 44,413.71669

Using TVM Solver:

N = 1*30
I% = 8
PV = -500000
PMT = This is what you are solving for.
FV = 0
P/Y = 1
C/Y = 1
PMT: END

Once all of the given parameters are entered in, solve for PMT.

PMT = 44,413.71669

So you would be able to withdraw $44,413.72 each year for 30 years.

You Try PF.11.A
After retiring, you want to be able to take $50,000.00 every year for a total of 25 years from your retirement account. The account earns 7% interest. How much will you need in your account when you retire?
Example 3
You want to be able to withdraw $65,000.00 from your account each year for 30 years after you retire. You expect to retire in 25 years. If your account earns 6% interest, how much will you need to deposit each year until retirement to achieve your retirement goals?

This problem requires two steps.

Step 1: Initially, figure out how much money you need to have in your account at retirement so that you can withdraw $65,000.00 per year for 30 years.

Step 2: After that, figure out how much money you need to deposit every year before retirement, so that you have the amount needed from Step 1 after 25 years.

Step 1: Find the amount you need to have in your account at retirement so that you can make annual withdrawals of $65,000.00 per year for 30 years.

N = 1*30
I% = 6
PV = This is what you are solving for.
PMT = -65,000
FV = 0
P/Y = 1
C/Y = 1
PMT: END

Once all of the given parameters are entered in, move your cursor to PV= and press ALPHA – ENTER.

PV = $894,714.02. You need to have $894,714.02 in your retirement account so that you can withdraw $65,000.00 per year for 30 years.

Step 2: Find the amount you need to deposit each year in order to have $894,714.02 in 25 years.

N = 1*25
I% = 6
PV = 0
PMT = This is what you are solving for.
FV = 894,714.02
P/Y = 1
C/Y = 1
PMT: END

Once all of the given parameters are entered in, move your cursor to PMT= and press ALPHA – ENTER.

PMT = -$16,307.70.

You need to deposit $16,307.70 each year for 25 years, so that you will have enough money in your account when you retire to withdraw $65,000.00 per year for 30 years.

Section PF.11 – Answers to You Try Problems

PF.11.A

You will need $582,679.16 in your account when you retire.

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College Mathematics - MAT14X - 3rd Edition Copyright © by Adam Avilez; Shelley Ceinaturaga; and Terri D. Levine is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License, except where otherwise noted.

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