Money strategies · Planning

Retirement and financial independence: the 4% rule

One day you may want to stop working, or simply have the choice to. That moment is called financial independence: your investments can pay your living costs for the rest of your life. How much do you need, and how long will it take? Two simple ideas answer both: the 4% rule and your savings rate.

👴 In one sentence You need about 25 times your yearly spending, and the share of your income you save decides how fast you get there.

The 4% rule

In 1994, financial planner William Bengen tested US market history since 1926. He asked: what is the largest amount a retiree could take out of a portfolio of shares and bonds in the first year, then raise every year with inflation, without running out of money for 30 years, even in the worst periods (like retiring just before the Great Depression)? The answer was about 4%. In 1998 three professors at Trinity University confirmed it in what became known as the Trinity study: with at least half in shares, a 4% withdrawal lasted 30 years in the vast majority of historical periods.

Money you need = Yearly spending × 25 (because 1 ÷ 4% = 25)

If you spend $30,000 a year, you need about 30,000 × 25 = $750,000. In the first year you take out 4% ($30,000); in later years you take the same amount plus inflation, whatever the market does, while the rest stays invested and keeps growing.

Sam's number

Sam (from our money plan) takes home $3,000 a month and, after the big three review, saves $755 of it.

Sam's financial independence number in $

Monthly spending: 3,000 − 7552,245

What Sam actually lives on. Spending, not income, is what the portfolio must pay for.

Yearly spending: 2,245 × 1226,940

In today's money. Inflation is already handled by the rule, so we can think in today's prices.

Target: 26,940 × 25673,500

4% of 673,500 is exactly 26,940: Sam's spending for a year.

With a $1,000-a-month state pension: (26,940 − 12,000) × 25373,500

Any pension or other income lowers the target a lot. Find your expected pension on your country's pension authority's website.

Your savings rate sets the date

Saving more does two things at once: more money goes in, and you get used to living on less, so you need less. That's why the savings rate matters far more than your salary. The table assumes you start from zero, earn 5% a year after inflation and stop when you reach 25 × your spending:

Savings rate	Years until financially independent
10%	about 52 years
15%	about 43 years
20%	about 37 years
25% (Sam)	about 32 years
30%	about 28 years
40%	about 22 years
50%	about 17 years
60%	about 13 years
70%	about 9 years

Sam is 28 and saves 25%, so if all $755 is invested, Sam reaches $673,500 at about 60, without counting any pension. Saving 40% instead would bring it to about 50. The savings goal calculator works it out for your own numbers.

FIRE: Financial Independence, Retire Early

The FIRE movement takes this idea to the extreme: people saving 50–70% of their income to be financially independent in their 30s or 40s. You don't need to go that far to benefit. Even if you love your job, having "enough" gives you the freedom to work part-time, take a career break or say no to a bad boss. Common variants:

Lean FIRE: independence on a small budget, often with a very frugal lifestyle.
Fat FIRE: a larger target that keeps a comfortable lifestyle.
Coast FIRE: you have saved enough that, with no more contributions, growth alone will reach your target by retirement age. You only need to earn what you spend.
Barista FIRE: the portfolio covers part of your costs and a relaxed part-time job covers the rest.

Limits of the 4% rule

⚠️ A rule of thumb, not a promise It was built on 30-year retirements and US market history, one of the best-performing markets of the last century. Keep these limits in mind:

Longer retirements need a lower rate. If you stop at 40, the money may need to last 50 years; many people then plan with 3–3.5% (×29 to ×33).
Sequence of returns. A crash in the first years of retirement hurts most, because you sell shares while they are low. Being flexible (spending a bit less after a bad year) helps a lot.
Fees. A 1% yearly fund fee eats a quarter of a 4% withdrawal. Cheap index funds matter even more here (see investing styles).
Taxes and health costs must be included in "spending".

Use the tax-advantaged accounts first

Most countries reward retirement saving. In the US: a 401(k) through your employer and an IRA. In the UK: a workplace pension and a stocks & shares ISA. In Romania: the mandatory private pension (Pillar II) and the optional Pillar III, where contributions up to a yearly limit are tax-deductible. If your employer adds money when you contribute (an employer match), contribute at least enough to get all of it: it's an instant, risk-free return.

✏️ Check yourself: Andrei spends $2,000 a month and expects a pension of $800 a month. Using the 4% rule, how much does he need invested? And how much would he need if he plans for a 50-year retirement at 3.5%?

Show the answer

The portfolio must cover (2,000 − 800) × 12 = $14,400 a year. At 4%: 14,400 × 25 = $360,000. At 3.5%: 14,400 ÷ 0.035 ≈ $411,400. If the pension only starts later, he also needs enough to cover the full $24,000 a year until it starts.