"How much do I need to retire?" is the most important financial question most people never rigorously answer. The common shortcuts ??? "$1 million," "25 times your salary," "80% of pre-retirement income" ??? are useful orientation points but terrible substitutes for actual math. Your retirement number is deeply personal, and the only way to know it is to build it from your own projected spending, income sources, and time horizon.
This guide walks through the full calculation ??? step by step, with real numbers ??? so you can arrive at a target that's actually calibrated to your life rather than a population average.
Step 1: Estimate Your Annual Retirement Spending
This is the most personal input and the one that most dramatically affects your result. Build it from the bottom up rather than applying a percentage to your current income.
Expenses that typically decrease in retirement:
- Commuting and work-related costs (clothing, lunches, parking)
- Mortgage payment (if the home is paid off)
- Retirement savings contributions (you're now withdrawing, not saving)
- Life insurance (often less necessary once wealth is accumulated)
- Childcare and college expenses (if children are grown)
Expenses that typically increase in retirement:
- Healthcare ??? premiums, out-of-pocket costs, and long-term care risk
- Travel and leisure (early retirement years)
- Home maintenance (more time at home, aging home systems)
A common result: retirement spending is roughly 70–80% of pre-retirement spending for most people ??? but this varies enormously. Someone with a paid-off home, simple lifestyle, and good health may need 55%. Someone with high travel aspirations, ongoing mortgage, or significant healthcare costs may need 100%+. Use your actual projected budget, not a percentage.
Step 2: Subtract Guaranteed Income Sources
Your retirement savings don't need to cover everything ??? only the gap between your spending and your guaranteed income. The most common guaranteed income sources:
Social Security
For most Americans, Social Security covers a meaningful portion of retirement spending ??? often $20,000–$50,000/year or more, depending on your earnings history and when you claim. Check your estimated benefit at SSA.gov using your actual earnings record. Crucially, delaying your claim from 62 to 70 increases your benefit by approximately 76% ??? and that larger benefit is inflation-adjusted for life.
Pension
If you have a defined benefit pension, its annual payment reduces the portfolio withdrawal you need. Treat it like Social Security ??? subtract it from your spending target before calculating the portfolio gap.
Part-time income
Many early retirees work part-time or generate income from consulting, rental properties, or other sources. Even $15,000–$20,000/year of supplemental income meaningfully reduces portfolio withdrawal pressure, especially in the early retirement years.
Step 3: Calculate the Portfolio Gap
Annual Spending − Social Security − Pension − Other Income
Example:
Annual spending: $72,000
Social Security (both spouses): −$38,000
Part-time income (first 5 years): −$12,000
Annual portfolio withdrawal needed: $22,000
This is the number your portfolio must sustainably produce each year. In this example, a couple spending $72,000/year only needs their portfolio to cover $22,000 ??? not $72,000. Social Security dramatically changes the retirement math.
Step 4: Apply the 4% Rule (and Understand Its Limits)
The 4% rule is the most widely used safe withdrawal rate benchmark. Based on historical research (the "Trinity Study"), withdrawing 4% of your portfolio in year one of retirement ??? then adjusting for inflation annually ??? has historically sustained a 30-year retirement in most market scenarios.
Example: $22,000 annual withdrawal × 25 = $550,000
Or: Annual withdrawal = Portfolio × 4%
The multiplier of 25 comes directly from dividing 1 by 4% (1 ÷ 0.04 = 25). If you need $22,000/year from your portfolio, you need $550,000. If you need $60,000/year, you need $1,500,000.
| Annual Portfolio Withdrawal Needed | Required Portfolio (4% Rule) |
|---|---|
| $20,000/year | $500,000 |
| $40,000/year | $1,000,000 |
| $60,000/year | $1,500,000 |
| $80,000/year | $2,000,000 |
| $100,000/year | $2,500,000 |
When to Adjust the 4% Rule
The 4% rule was developed for a 30-year retirement horizon. Adjust it based on your circumstances:
- Retiring early (before 60) ??? Use 3–3.5% for a 40+ year horizon. More years means more market uncertainty and more time for sequence-of-returns risk to compound.
- Retiring at 70+ ??? A 3.5%–4.5% withdrawal rate is more defensible with a shorter horizon.
- Very conservative portfolio (mostly bonds) ??? Lower expected returns mean a lower safe withdrawal rate, possibly 3–3.5%.
- Flexible spending in retirement ??? If you can reduce spending in bad market years (cutting discretionary travel, for example), you can safely use a higher initial withdrawal rate because you're not mechanically withdrawing regardless of conditions.
Putting It All Together: A Complete Example
| Variable | Example Values |
|---|---|
| Annual retirement spending | $85,000 |
| Social Security (both spouses, age 67) | −$46,000 |
| Small rental income | −$9,000 |
| Annual portfolio withdrawal needed | $30,000 |
| Safe withdrawal rate (4%, 30-year horizon) | 4% |
| Required portfolio at retirement | $750,000 |
A couple spending $85,000/year only needs $750,000 in retirement savings ??? not $2.1 million ??? because Social Security and rental income cover most of the spending. The number is deeply personal, which is why generic benchmarks mislead so many people.
Project Your Retirement Number
The Retirement Calculator lets you model your contribution rate, employer match, expected return, and retirement age to see whether you're on track for your specific target.
Know Where You Stand Today
Your retirement number is the finish line. Your net worth is your current position. Use the Net Worth Calculator to see your total assets, liabilities, and how far you are from your goal.