401k Safe Withdrawal Rate (SWR) Calculator

Calculate safe withdrawal rates for retirement portfolios. Test sustainability over 10-50 years with different withdrawal strategies.

Total 401k/IRA balance at retirement

Classic 4% rule, but adjust for market conditions

How long must savings last (life expectancy - retirement age)

For inflation-adjusted withdrawals

Typically 6-8% for balanced retirement portfolio

Used for life expectancy calculation

How you adjust withdrawals over time

Annual Withdrawal = Savings × SWR. Year 1: $1M × 4% = $40k. Year 2: $40k × (1 + inflation). Constant Dollar: Fixed amount inflated. Constant %: Withdraw % of current balance.
$1M savings, 4% SWR, 30 years, 3% inflation, 7% return: Year 1 = $40k ($3,333/mo), Total withdrawals = $1.93M, Success probability = 90%. Final balance = $1.2M.

What is the 4% Safe Withdrawal Rate?

The 4% rule (from the Trinity Study) suggests withdrawing 4% of retirement savings in year 1, then adjusting for inflation each year. It has a 95%+ success rate over 30 years. However, for 40+ year retirements (early retirement), use 3.5% or lower. For 15-20 years, 5% may be safe.

How does withdrawal strategy affect sustainability?

Constant Dollar (4% rule): Withdraw fixed amount adjusted for inflation. Safest for long retirements. Constant Percentage: Withdraw fixed % of balance (e.g., 4% of whatever remains). Fails if market crashes early. Dynamic: Reduce withdrawals after market drops, increase after gains. Best for longevity but requires discipline.

What SWR should I use for early retirement?

For FIRE (retiring at 40-50): Use 3.0-3.5% for 40-50 year retirement. Traditional retirement (65+): 4.0-4.5% for 25-30 years. Very early retirement (30s): 2.5-3.0% for 50+ years. Adjust based on: market valuations (lower if P/E high), flexibility to cut spending, Social Security/Pension kicking in later.

How do I calculate inflation-adjusted withdrawals?

Year 1: $1M × 4% = $40,000. Year 2: $40,000 × (1 + inflation). If 3% inflation, Year 2 = $41,200. Year 3: $41,200 × 1.03 = $42,436. This maintains purchasing power. With Constant Percentage, you withdraw 4% of current balance each year (amount fluctuates).