What is the 4% rule?
The 4% rule is a planning shortcut: if you withdraw about 4% of your portfolio in your first year of retirement, then adjust that dollar amount each year for inflation, your money has historically had a high chance of lasting 30 years.
In plain English, it converts your annual spending target into a rough nest egg number. The formula is simple: annual spending divided by 0.04. If you think you need $60,000 per year in retirement spending, the rough target portfolio is $1.5 million.
How this calculator works
Step 1: Estimate your required nest egg
The calculator uses your annual spending estimate and chosen withdrawal rate to calculate how much invested capital you may need at retirement.
- Required portfolio = Annual spending ÷ (Withdrawal rate / 100)
- Example: $80,000 spending at 4% = $2,000,000 target portfolio
Step 2: Project your portfolio growth
Next, it projects your future portfolio based on:
- Current invested savings
- Annual contributions
- Expected annual return
- Years until retirement
The projection assumes contributions are made yearly and returns are compounded annually.
Step 3: Compare target vs projected balance
You get an immediate “on track” view, plus your shortfall or surplus, your implied first-year safe withdrawal, and the annual contribution needed to hit your target by your planned retirement age.
How to interpret your results
- Required portfolio: your planning target using the 4% rule (or your custom rate).
- Projected portfolio: what your savings could grow to by your retirement age.
- Shortfall/surplus: how far above or below your target you are with current assumptions.
- Sustainable first-year withdrawal: projected portfolio × withdrawal rate.
Important limitations of the 4% rule
1) Market sequence risk
Poor returns in the first years of retirement can hurt sustainability more than poor returns later. This is called sequence-of-returns risk.
2) Historical context
The original rule was based on U.S. historical market data and a 30-year retirement horizon. Your region, asset allocation, and timeline may differ.
3) Taxes and fees
Your real spending power depends on after-tax withdrawals and investment costs. The calculator does not model taxes, account type, or advisor fees.
4) Personal flexibility
Real retirees often adjust spending up or down. If you're willing to be flexible in bad years, your portfolio may last longer than a rigid model suggests.
Ways to improve your retirement plan
- Run conservative scenarios (lower return, lower withdrawal rate)
- Increase annual contributions even modestly
- Delay retirement by 1–3 years to compound more and withdraw for fewer years
- Reduce fixed expenses before retirement
- Build non-portfolio income streams (part-time work, rental income, pensions)
Bottom line
The 4% rule is a useful starting framework—not a guaranteed promise. Use it to set a target, then stress-test your plan with multiple assumptions. A strong retirement strategy is less about one perfect percentage and more about building a margin of safety.