How Much Do I Need to Retire? The Real Number
The 4% rule, Social Security, and the exact savings target you need to retire comfortably. Stop guessing — here's the math.
Most people have no idea how much they need to retire. They guess a round number — $1 million, $2 million — without any math behind it. The truth is, your retirement number is personal. But there's a proven formula to calculate it, and it's simpler than you think.
The 4% Rule: Your Starting Point
The 4% rule comes from the Trinity Study: a landmark 1998 analysis showing that retirees who withdraw 4% of their portfolio in year one — then adjust for inflation each year — have a 95%+ chance of never running out of money over 30 years.
The math works backwards. If you need $50,000/year in retirement and Social Security covers $20,000, you need $30,000/year from savings. Divide by 4%: $30,000 ÷ 0.04 = $750,000. That's your number.
The Simple Formula
Retirement Number = (Annual expenses − Social Security income) ÷ 0.04
- Annual expenses $60,000, no Social Security: $60,000 ÷ 0.04 = $1,500,000
- Annual expenses $60,000, SS pays $18,000: $42,000 ÷ 0.04 = $1,050,000
- Annual expenses $40,000, SS pays $15,000: $25,000 ÷ 0.04 = $625,000
What Will You Actually Spend in Retirement?
Most financial planners use 70-80% of pre-retirement income as a baseline. If you earn $80,000 now, plan for $56,000-$64,000/year in retirement. But this varies hugely by lifestyle.
Expenses that drop in retirement: mortgage (if paid off), commuting, work clothes, payroll taxes. Expenses that rise: healthcare, travel, hobbies. Healthcare is the wild card — budget $5,000-$15,000/year per person for premiums and out-of-pocket costs.
💡 The 4% rule assumes a 30-year retirement. Retiring at 55 instead of 65? Consider a 3-3.5% withdrawal rate to make money last 40+ years.
How Long Will You Need the Money?
Average life expectancy in the US is 79. But averages are misleading — if you make it to 65, your life expectancy jumps to 84 for men and 87 for women. Plan for at least 25-30 years of retirement, possibly more.
The Power of Starting Early
- Saving $500/month from age 25 at 7% return = $1.3M at 65
- Saving $500/month from age 35 at 7% return = $606K at 65
- Saving $500/month from age 45 at 7% return = $260K at 65
Starting 10 years earlier more than doubles your outcome. The math is brutal — every decade you delay roughly halves what you'll accumulate.
Retirement Account Priority Order
- 1401(k) up to employer match — it's an instant 50-100% return
- 2HSA if available — triple tax advantage
- 3Roth IRA — $7,000/year limit, tax-free growth
- 4Max out 401(k) — $23,000/year limit
- 5Taxable brokerage — no limits, flexible
Use our Retirement Calculator to see exactly how much you need based on your age, income, and expenses — plus a year-by-year savings plan to get there.
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