The 4% Rule: How Much You Need to Retire (and What It Misses)
How much do you need to retire? The most famous answer in personal finance is the 4% rule — a simple shortcut that turns a terrifyingly vague question into a single number. It’s a great starting point, as long as you understand what it does and doesn’t promise.
What the 4% rule says
The rule has two halves that say the same thing from opposite ends:
- Spending side: in your first year of retirement, you can withdraw 4% of your portfolio, then increase that dollar amount with inflation each year — and your money should last about 30 years.
- Saving side (the “25× rule”): flip it around and you get your target nest egg — you need roughly 25 times your annual spending (because spending ÷ 4% = spending × 25).
So if you spend $40,000 a year, the rule suggests a portfolio of about $1,000,000 ($40,000 × 25). Here’s how the target scales:
| Annual spending from savings | Nest egg (25×) |
|---|---|
| $30,000 | $750,000 |
| $40,000 | $1,000,000 |
| $50,000 | $1,250,000 |
| $60,000 | $1,500,000 |
| $80,000 | $2,000,000 |
The retirement drawdown calculator lets you test a withdrawal rate against your own balance and time horizon.
Where it came from
The rule traces back to research in the 1990s (the work of advisor William Bengen and the related “Trinity study”). Looking at decades of US market history, researchers asked: what’s the highest starting withdrawal rate that would have survived every 30-year stretch, including retirements that began right before a crash? The answer landed around 4%, assuming a balanced portfolio of roughly 50–75% stocks with the rest in bonds.
The point of the rule was never precision — it was to find a rate conservative enough to survive history’s worst starting years, not just the average.
The big thing it misses: timing
The 4% rule’s most important caveat is sequence of returns risk — the danger that a market crash in your early retirement years does outsized damage, because you’re selling investments while they’re down. Two retirees with the same average return can have wildly different outcomes depending on when the bad years hit. A single steady “4%” number can’t capture that lumpiness, which is why it’s a guideline, not a guarantee. We dig into this in sequence of returns risk.
Adjusting the rule for real life
- Retiring early? A 30-year assumption doesn’t fit a 45-year retirement. Many planners drop the starting rate toward 3.5% (about 28–30× spending) for very long horizons.
- Don’t forget CPP and OAS. Government benefits cover part of your spending, so your portfolio doesn’t have to supply the whole budget. The 25× target applies to the slice your savings must cover, which is often less than your total spending.
- Stay flexible. Trimming spending a little after bad market years dramatically improves how long money lasts — far more than getting the exact starting percentage right.
- Keep a cash cushion. A year or two of spending in cash/bonds lets you avoid selling stocks in a downturn.
The takeaway
- The 4% rule: spend 4% of your starting portfolio (rising with inflation), or save about 25× your annual spending.
- It’s a solid starting estimate, born from surviving the worst of US market history — not a promise.
- Adjust for an early retirement, CPP/OAS, and flexibility, and remember that the order of returns matters as much as the average.
See how long your savings might last — and what a sustainable withdrawal looks like — in the retirement drawdown calculator.
This is general education, not financial advice. Your own horizon, spending, and other income should shape your plan.