Common rule: aim for 25× your expected annual retirement expenses (the inverse of the 4% safe withdrawal rule). If you'll spend $50K/year, target $1.25M. To reach this, save 10–15% of gross income starting in your 20s, or 20%+ if starting in your 40s. The calculator works backward from your retirement age + spending to show required monthly savings.

The 4% rule (Trinity Study) says you can safely withdraw 4% of your portfolio in year 1 of retirement, then adjust that dollar amount for inflation each subsequent year. Statistically lasts 30+ years in 95% of historical periods. For longer retirements (50 years), drop to 3.25–3.5% to handle sequence-of-returns risk.

3% is the long-term US average. Recent years trended 1.5–2.5% before the 2022 spike. Use 3% for conservative US planning; 4–5% for stress-testing. Different countries vary widely — use your own country's long-term CPI average. The calculator shows both nominal and inflation-adjusted retirement values so you understand real purchasing power.

Order: (1) 401(k) up to employer match (free money — usually 3–6% of salary). (2) Roth IRA up to limit ($7K in 2024) for tax-free growth. (3) Back to 401(k) until you hit 15% total or max contribution. Exception: high earners may prefer traditional 401(k) over Roth if expecting lower tax bracket in retirement.

As early as possible — compounding's power is exponential in time, not contribution. Saving $5,000/year from age 22 to 32 (10 years, $50K) → ~$1.5M at 65. Saving $5,000/year from age 32 to 65 (33 years, $165K) → ~$880K at 65. Starting 10 years earlier with 1/3 the contributions produces 70% MORE money. Start now.

Social Security replaces 30–40% of pre-retirement income for average earners (less for high earners). Don't count on it as your primary plan — political risk and demographic challenges make future benefits uncertain. Treat it as a bonus that reduces your required portfolio size. The calculator focuses on your investment portfolio independent of any government programs.