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### Savings Withdrawal Help

You will find the savings withdrawal calculator to be very flexible. While it is most frequently used to calculate how long an investment will last assuming some periodic, regular withdrawal amount, it will also solve for the " Starting Amount", "Annual Interest Rate" or "Regular Withdrawal Amount" required if you want to dictate the duration of the payout. That is, if the withdrawals must last for say 25 years, it will calculate one of these other three values.

Enter any three values and enter a "0" (zero) for the one unknown value.

A note or two about "Compounding Frequency". Selecting he "Exact/Simple" option sets the calculator so it will not compound the interest. Also, the exact number of days between withdrawal dates is used to calculate the interest for the period. The "Daily" option uses the exact number of days between dates, but daily compounding is assumed. (The interest earned each day is added to the principal amount each day.) The "Exact/Simple" compounding option is the most conservative setting. That is, using it will result in the lowest future value. Daily compounding will result in nearly the greatest future value (except for "Continuous Compounding".

The other compounding frequencies are based on periods of time other than days. Each period is assumed to be of equal length for the purposes of interest calculations. That is, assuming a balance of $10,000, the interest earned for January will be the same interest earned for February given the same interest rate.

## Pat Sturgis says:

Why do I repeatedly get “NaN” inserted in the Number of Withdrawals field, where I have inserted a “0,” with the other 3 fields filled with values? The calculator worked once, with a different interest rate, but hasn’t worked since. I have tried changing browsers, re-booting.

## Karl says:

"NaN" means "not a number". A user should never see that. It means the calculator is not show an appropriate message.

Without knowing your specific inputs, I can’t tell you what the exact reason is you are seeing NaN. However, I can make a guess.

My guess is, you increased the interest rate and now the amount being withdrawn is less then the amount earned in interest for the period. Which means the number of periods is infinite. You can test my guess by reducing the interest rate a bit (say by 0.5 at a time).

If you give me your exact inputs, I’m also happy to let you know the reason.

## BobA says:

Where is the money “stored” to earn the interest? Stocks, cash savings, combo. I am completely ignorant on this subject.

## Karl says:

If your question is, where should you invest the money, I’m afraid I’m not qualified to provide investment advise. I am happy to answer any questions you have about what calculator to use, or how to use a calculator.

## Guy says:

this is really a great tool Karl, thank you

## Karl says:

Thank you, Guy. I’m happy to hear you found it useful.

## Greg Taylor says:

This is exacty what I was looking for as I approach retirement! THANKS!

## Karl says:

You’re welcome. Happy retirement!

## Aldo says:

Is this based on what we use to call a “sinking fund” equation back in engineering school?

## Gary says:

How to choose compounding frequency on mutual fund investments?

## Karl says:

I’m sorry, but I don’t understand what you mean. The compounding frequency is the compounding frequency. It does not matter if it’s for a loan, a mutual fund, or whatever. If you are asking "what" compounding frequency you should pick for a mutual fund, I would suggest annually, as that is most conservative.

## Gary says:

Forgive my naivete’; I was simply asking what method of compounding to choose and have entered into the box on your calculator, when the monies are currently held in a mutual fund account.

## Karl says:

It’s a good question. I just wasn’t sure what your question was.

The compounding option generally is made available for savings and similar accounts that specify a compounding frequency.

But the calculator can be used for mutual funds, and what you set it to depends on how you set the rate. Say, for example, your mutual fund states they average a 7% annual return. Then I would set compounding to annually.

However, if again, for example, you see that your fund returned 2% for the last quarter then you need to do a little arithmetic. Since the calculator asks for an annual rate, you should enter 8%. And since the return was for a quarter, I would set the compounding to quarterly.

But the bottom line is when projecting how long income from a mutual fund might last, it can only be an estimate since we do not know how the fund will perform in the future. And the “error” from picking the “wrong” compounding frequency may pale compared to the change in the fund’s future performance. So compounding for a mutual fund is definitely not something one needs to stress out over.