The 4% rule states that if you withdraw 4% of your retirement portfolio in your first year of retirement, then adjust that dollar amount for inflation every year after, your savings have historically lasted at least 30 years across nearly every rolling period in U.S. market history since 1926 (the Trinity Study).

Is the 4% rule too aggressive or too conservative today?

Opinions are split. Some researchers argue 4% is too aggressive given lower expected future stock and bond returns compared to the 20th century, and suggest 3.3%–3.8% instead. Others note the original 4% figure was calibrated to the worst historical 30-year period, meaning most retirees who followed it ended up with more money than they started with, not less.

How much do I need to save monthly to retire with $1 million?

Starting from $20,000 saved at age 30 with a 7% average annual return, $500/month reaches roughly $1,130,650 by age 65. Starting the same plan at age 40 instead reaches only about $519,544 by 65 — less than half — because 10 fewer years of compounding removes far more than 10 years' worth of contributions.

What does 'real' vs 'nominal' retirement savings mean?

Nominal savings is the actual dollar amount in your account. Real savings discounts that amount by inflation to show what it can actually buy in today's purchasing power. A nominal balance of $1,130,650 in 35 years, discounted at 3% annual inflation, is worth about $401,814 in today's dollars — the number that matters for planning your actual lifestyle.

How Much You Need to Retire (4% Rule)

Q: How much money do I need to retire?

Under the 4% rule, you need 25 times your desired annual spending saved. That means $1,000,000 to support $40,000/year in withdrawals, $1,500,000 for $60,000/year, or $2,000,000 for $80,000/year — before accounting for Social Security or other income.

Q: Does the 4% rule account for Social Security?

No. The 4% rule applies only to your investment portfolio. Social Security, a pension, or rental income reduce how much your portfolio needs to cover, effectively lowering your required nest egg below the standard 25x figure. Check your estimated benefit at ssa.gov before setting a savings target.

What is the 4% rule for retirement?

The 4% rule comes from a 1994 analysis by financial planner William Bengen, later expanded by three professors at Trinity University into what's known as the Trinity Study. It tested every 30-year retirement window in U.S. market history since 1926 and found that withdrawing 4% of a stock-and-bond portfolio in year one, then increasing that dollar amount each year to keep pace with inflation, meant the money lasted at least 30 years in nearly every historical scenario.

Flip the math around and the 4% withdrawal rate becomes a savings target: if 4% of your portfolio needs to cover a year of spending, your portfolio needs to be 25 times your annual spending (1 ÷ 0.04 = 25).

Desired Annual Spending	Nest Egg Needed (25x)
$40,000/year	$1,000,000
$60,000/year	$1,500,000
$80,000/year	$2,000,000
$100,000/year	$2,500,000

How much will $500/month become by retirement?

Take a 30-year-old with $20,000 already saved, contributing $500 a month, earning a 7% average annual return, retiring at 65. Using monthly compounding — growth applied every month, then that month's contribution added — the balance reaches $1,130,650 by retirement. Of that, $230,000 came from contributions (starting balance plus 35 years of $500/month) and $900,650 came purely from investment growth.

Adjusted for 3% average annual inflation over those 35 years, that $1,130,650 is worth $401,814 in today's purchasing power — the number that actually matters for picturing your future lifestyle. Under the 4% rule, $401,814 in real terms supports roughly $16,073/year in today's-dollar spending, which is why most savers need to push contributions well above $500/month to hit a comfortable real retirement number.

Raising the contribution to $800/month, with everything else unchanged, lifts the nominal balance to $1,670,967 ($593,834 real) — a $540,317 nominal difference from just $300/month more, almost entirely compounding at work over 35 years. Model your own contribution, return, and inflation assumptions with our Retirement Savings Calculator.

What does waiting 10 years to start actually cost you?

Take the same saver — $20,000 starting balance, $500/month, 7% return — but starting at age 40 instead of 30, retiring at the same age 65. Only 25 years of compounding instead of 35 produces $519,544 nominal ($248,137 real) — less than half of the $1,130,650 reached by starting a decade earlier.

Start Age	Years Compounding	Nominal Balance at 65	Real Balance (Today's $)
Age 30	35 years	$1,130,650	$401,814
Age 40	25 years	$519,544	$248,137

Both scenarios: $20,000 starting balance, $500/month contribution, 7% annual return compounded monthly, 3% annual inflation. Calculated using the same month-by-month compounding formula as accurate.software's Retirement Savings Calculator.

The 10-year delay only costs 10 years of contributions — $60,000 less principal put in — but it removes $611,106 in nominal ending balance. The gap is almost entirely lost compounding time, not lost contributions: money invested in your 30s has an extra decade to double and redouble before you need it.

Is the 4% rule still safe in 2026?

The 4% figure was deliberately calibrated to the worst 30-year stretch in the historical dataset — the retiree who started in 1966, right before a decade of high inflation and flat markets. In most other historical periods, a 4% withdrawal rate left retirees with more money after 30 years than they started with, not less.

Critics argue that today's starting valuations and lower expected forward returns on both stocks and bonds make a straight 4% too aggressive for a new retiree, and suggest 3.3%–3.8% as a more conservative floor. Others point to more flexible approaches — spending guardrails that cut withdrawals slightly in down markets and restore them in up markets — as a way to safely start closer to 4-5% without the rigid, worst-case assumption baked into the original rule.

How do you calculate your own retirement number?

Estimate your desired annual spending in retirement, in today's dollars
Divide by your target withdrawal rate (0.04 for the standard 4% rule, 0.035 for a more conservative target)
Subtract the value of guaranteed income sources like Social Security or a pension, since those reduce what your portfolio alone needs to cover
Use a savings calculator to work backward from your current age, savings, and monthly contribution to see if you're on pace to reach that number

Model your full retirement plan

Our Retirement Planning Model spreadsheet runs a 50-year projection with employer match, Monte Carlo percentiles, your FIRE target under the 4% rule, Roth vs. Traditional comparison, and Social Security claim-age optimization — no subscription required.

Frequently asked questions about the 4% rule

How much money do I need to retire?

Under the 4% rule, you need 25 times your annual spending saved: $1,000,000 for $40,000/year, $1,500,000 for $60,000/year, $2,000,000 for $80,000/year — before Social Security or other guaranteed income.

What is the 4% rule?

Withdraw 4% of your portfolio in year one of retirement, then adjust that dollar amount for inflation every year after. Historically, this has made savings last at least 30 years in nearly every rolling period since 1926.

Does the 4% rule account for Social Security?

No — it applies only to your investment portfolio. Guaranteed income like Social Security or a pension reduces how much your portfolio needs to cover, lowering your required nest egg below the standard 25x figure.

How much do I need to save monthly to reach $1 million?

Starting at age 30 with $20,000 saved, $500/month at a 7% return reaches roughly $1,130,650 by 65. Starting the same plan at 40 instead reaches only about $519,544 — less than half — because a decade less compounding outweighs 10 fewer years of contributions.

Data sources: Compound growth figures calculated independently using standard monthly-compounding methodology, verified against accurate.software's Retirement Savings Calculator. Withdrawal rate research per the original Trinity Study methodology. Social Security benefit estimation guidance from the Social Security Administration. Long-run inflation assumption based on U.S. Bureau of Labor Statistics CPI data. Analysis by the staff at accurate.software.