How much do you really need to retire?

“How much do I need to retire?” is the most common personal-finance question and the most poorly answered. The honest answer involves three numbers and one rule. Together they take 5 minutes to calculate and replace most of what you'd find in a 300-page personal-finance book.

The 25× rule

The rule: you need 25× your annual spending to retire safely.

That's it. Not 25× your income — 25× your spending. Annual spending of $50,000 means you need $1.25M to retire. Annual spending of $80,000 means $2M.

The math comes from the 4% rule, which says you can safely withdraw 4% of a diversified portfolio each year and the portfolio will last 30+ years (in most historical scenarios). 4% withdrawal = 25× the annual amount needed.

Why “spending” is the variable, not income

Most people calculate their retirement number based on their income at the time of retirement. This is the wrong denominator.

Two people earning $200K, one spending $80K and the other spending $180K, have completely different retirement targets:

• Person A: needs 25 × $80K = $2M
• Person B: needs 25 × $180K = $4.5M

Person A can retire on less than half what Person B needs. The income was identical. The spending — the actual cost of supporting their life — determines the finish line.

This is why lifestyle inflation is so damaging. Every extra $10K of annual spending adds $250K to your retirement target.

Your actual number, in three steps

Step 1: Calculate your real annual spending

Not your guess — your actual spending. Pull the last 12 months of bank + credit card statements. Add up the total of all outflows. That's your real number.

Most people's real number is higher than their guess by 20-40%.

Step 2: Adjust for retirement

Some line items change in retirement:

• Down: commute, work clothes, lunches, payroll taxes, retirement contributions (you stop saving for retirement when you're in it).
• Up: healthcare (significantly, until Medicare at 65), travel/leisure (often).
• Variable: housing (paid off vs not), kids' expenses (probably down), gifts/family obligations.

Most retirees end up spending 70-80% of their pre-retirement spending. Use 75% as a default if you don't want to model it precisely.

Step 3: Multiply by 25

Real annual spending × 0.75 × 25 = your retirement target.

Example: $80K real annual spending → $60K retirement spending × 25 = $1.5M target.

The savings rate that gets you there

Once you have a target, the question becomes: what savings rate gets you there by when?

Rough lookup table (assuming you start with $0, 10% annualized returns, contributions inflate with raises):

• 10% savings rate: ~50 working years to retirement
• 15% savings rate: ~43 years
• 20% savings rate: ~37 years
• 25% savings rate: ~32 years
• 30% savings rate: ~28 years
• 40% savings rate: ~22 years
• 50% savings rate: ~17 years
• 65% savings rate: ~10 years

Two things to notice. First, the relationship is non-linear — doubling your savings rate doesn't halve the time, it roughly thirds it. Second, the rate at which you live below your means is far more important than your income.

What about Social Security?

Social Security is real and you should plan around it as real, but with the right amount of cushion.

Current average benefit: ~$1,900/month for a worker retiring at 67. That's ~$22,800/year. If your retirement spending target is $60K, Social Security covers ~38% of it. The rest comes from your portfolio.

Sensible planning: include Social Security in your numbers but don't treat it as the dominant pillar. Build your savings to cover the gap, not to fully replace what SS provides.

Three common mistakes

1. Overestimating the target

“You need $5M to retire” articles are mostly wrong. They assume current high-income lifestyle continued forever. The right target is based on YOUR spending, not someone's aspirational scenario.

2. Underestimating compounding

$1.5M sounds impossibly far away. At 30 years and a 15% savings rate on $80K income, the math gets there. People underestimate compounding because the curve is back-loaded.

3. Treating it as a 30-year project starting at 45

Compounding rewards early decades disproportionately. Someone starting at 25 with $300/month becomes a millionaire by 65. Someone starting at 45 with the same $300/month barely cracks $200K. Same monthly contribution. Different lifetime math.

The takeaway

Calculate your real annual spending. Multiply by 0.75 for retirement adjustment, then by 25. That's your target. From there, your savings rate and starting age determine the timeline.

Most people's number is smaller than they feared. The bigger question is what savings rate they're actually on track for.