The 4% Rule Explained: What It Says, and What It Does Not
The 4% rule says you can take 4% of your savings in the first year of retirement, raise that amount with inflation each year after, and expect the money to last about 30 years.
Turned around, it gives the figure everyone quotes: you need about 25 times the yearly spending your savings have to cover.
It is the most repeated number in retirement planning, and one of the least read. Here is where it came from, what it assumes, and what a business owner should change before using it.
The rule applies to savings, not to everything you own. Example data.
The short version
Take 4% of savings in year one, then adjust that dollar amount for inflation.
It implies savings of 25 times the spending they must cover.
It comes from studies of past US market returns over 30 year periods.
It is a starting estimate. It is not a promise, and it was never meant as one.
Where it came from
The idea was set out in 1994 by a financial planner, William Bengen, in a paper in the Journal of Financial Planning. He tested withdrawal rates against historical US stock and bond returns and found that about 4% had survived every 30 year period he examined.
In 1998 three professors at Trinity University, Philip Cooley, Carl Hubbard and Daniel Walz, published a similar analysis. It became known as the Trinity study, and the two together are the source of the rule.
The sum
Yearly spending your savings must cover | Savings needed at 4% |
|---|---|
$15,000 | $375,000 |
$25,200 | $630,000 |
$40,000 | $1,000,000 |
$60,000 | $1,500,000 |
The left column is not your whole budget. It is what is left after Social Security and any other income. This is the step most people skip, and it is why the figure they arrive at feels impossible.
The step that makes it realistic
Line | A year |
|---|---|
What she expects to spend | $48,000 |
Social Security at 67, at $1,900 a month | $22,800 |
The gap her savings must cover | $25,200 |
Savings needed at 4% | $630,000 |
Twenty-five times $48,000 is $1,200,000. Twenty-five times the gap is $630,000. Same person, same life, and a target that is nearly half the size because she counted her benefit first.
What the rule assumes
A retirement of about 30 years. Longer needs a lower rate.
Money invested in a mix of stocks and bonds throughout.
The future resembling the US past. Nobody can promise that.
The same spending every year, adjusted for inflation. Real spending moves.
No fees and no tax. Both come out of the 4%.
None of these makes it wrong. They make it an estimate with conditions, which is what its authors said it was.
How much the rate matters
Withdrawal rate | Multiply the gap by | Savings for a $25,200 gap |
|---|---|---|
3% | 33.3 | $840,000 |
3.5% | 28.6 | $720,000 |
4% | 25 | $630,000 |
5% | 20 | $504,000 |
One percentage point either way moves the target by more than $100,000. That is a reason to hold the number loosely. It tells you the neighborhood, not the address.
The savings line is the one the rule is talking about. Example data.
What changes for a business owner
Your business may not count. A business that depends on you is an income, not savings. The Federal Reserve found the typical owner of a business with no employees reported no net value for it.
You can taper. Working a lighter schedule for a few years reduces the gap, and with it the target.
Your income history is uneven. So is your saving. A percentage of each payment gets further than a fixed monthly amount.
Your home is not in the sum unless you plan to sell or downsize.
The second point is worth a line of arithmetic. If she earns $12,000 a year from a lighter schedule, her gap falls from $25,200 to $13,200, and the savings needed for those years falls from $630,000 to $330,000.
Modeled in La Soglia
In the free Net Worth Tracker, add up the lines the rule applies to: retirement accounts and other invested savings. Leave out the home and the business. Then set that total beside the target.
Line | Amount |
|---|---|
Retirement accounts and invested savings today | $210,000 |
Target at 4% for a $25,200 gap | $630,000 |
Share of the way there | 33% |
A third of the way is a position, not a verdict. Updated each quarter, it becomes a line that moves, which is a great deal easier to act on than a rule.
So, should you use it?
As a first estimate, yes. It turns a vague worry into a number in about a minute, and the number is usually smaller than feared once Social Security is counted.
As a plan, no. A plan uses your own spending, your own health and your own willingness to adjust in a bad year. For the figures behind the gap, see our posts on what each claiming age pays and on average retirement savings.
Find your share of the way, free
La Soglia, the free membership of the Money Mastery System, holds your savings, your home, your business and your debts in one place, with no bank connection and no card.
Bring it to the Collective
What does your gap come to? The Money Mastery Collective has a discussion feed open on the free membership. Work it out and bring your questions.
Questions we hear
What is the 4% rule?
A guideline that you can withdraw 4% of your savings in the first year of retirement, adjust that amount for inflation each year, and expect the money to last about 30 years.
How much do I need to retire using the 4% rule?
About 25 times the yearly spending your savings must cover, after Social Security and other income.
Is the 4% rule safe?
It is based on past US market returns and is not a guarantee. A lower rate, or flexibility in a bad year, makes savings last longer.
Does my business count toward the 4% rule?
Only if it could be sold. A business that depends on you working in it is an income, not savings.
References
The 4% withdrawal rate was set out by William P. Bengen in "Determining Withdrawal Rates Using Historical Data", Journal of Financial Planning, October 1994, and examined by Philip L. Cooley, Carl M. Hubbard and Daniel T. Walz in "Retirement Savings: Choosing a Withdrawal Rate That Is Sustainable", AAII Journal, February 1998. The finding on business value is from the Federal Reserve's 2022 Survey of Consumer Finances. Every table is our own worked example.
Start free with La Soglia
La Soglia is the free membership of the Money Mastery System. It gives you the Net Worth Tracker, where everything you own and everything you owe sits in one place, and the Money Mastery Collective. There is no card to enter and no bank connection.
Keep in touch
Donna shares a short version of posts like this one on Instagram and LinkedIn. Follow along there, or find everything in one place on our links page.
A note on what this is
This article is educational. The Money Mastery System is an educational tool, not financial software, and nothing here is legal, tax, investment or financial advice. A withdrawal rate is an estimate based on the past, and nothing here predicts investment returns or how long your own savings will last. For guidance on your own circumstances, please speak with a qualified professional who knows them.
Comments