How Much Do I Need to Retire? (The Honest Answer)

Everyone has heard a retirement number thrown around. One million dollars. Two million. Some financial pundit on TV once said three million is the new one million. If you’ve spent any time googling this question, you’ve probably walked away more confused than when you started.

The reason retirement numbers vary so wildly is that they’re being applied to everyone — when in reality your number depends entirely on your life. What you spend. When you plan to stop working. What inflation will do to your purchasing power between now and then.

Let’s cut through the noise and figure out your actual number.

Why “A Million Dollars” Is the Wrong Starting Point

The problem with generic retirement figures is that they start with a number and work backwards. But your retirement plan should start with your life and work forwards.

A couple spending $3,000 a month in retirement needs roughly $900,000. A family spending $8,000 a month needs roughly $2,400,000. These aren’t close to each other — and neither of them necessarily needs “a million dollars.”

Your retirement number is a function of one thing above all else: how much you plan to spend each month when you’re no longer working.

Everything else — your investment returns, your savings rate, your timeline — flows from that.

The Formula Behind Every Retirement Number

The most widely used framework for calculating a retirement number is the 4% rule. The idea is straightforward: if you withdraw 4% of your portfolio each year, your money has historically had a very high probability of lasting 30 years or more across different market conditions.

Working backwards from that rule gives you a simple formula:

Retirement target = (Annual expenses) ÷ 4%

Or equivalently: annual expenses multiplied by 25.

Let’s put some real numbers on it:

Monthly Expenses	Annual Expenses	Retirement Target
$2,500	$30,000	$750,000
$4,000	$48,000	$1,200,000
$6,000	$72,000	$1,800,000
$8,000	$96,000	$2,400,000
$10,000	$120,000	$3,000,000

This is why “a million dollars” became the shorthand — it roughly covers someone spending $3,300 a month in retirement. But that number is completely wrong for someone spending $6,000 a month, and completely unnecessary for someone living on $2,500.

The Part Most People Forget: Inflation

Here’s where most retirement calculators quietly mislead you.

When you enter “$4,000 a month” into a calculator, you’re thinking in today’s dollars. But you’re not retiring today — you’re retiring in 15, 20, or 30 years. And in 25 years, $4,000 today will have the purchasing power of roughly $8,000 or so at typical inflation rates. Your lifestyle costs twice as much in nominal terms even though nothing about your life changed.

This means your retirement target isn’t $1,200,000 based on $4,000 a month. It’s closer to $2,400,000 once you account for what $4,000 will actually cost in the future.

The math for inflation adjustment looks like this:

Inflation-adjusted expenses = Current expenses × (1 + inflation rate)^years until retirement

At 3% inflation over 25 years, a $4,000 monthly budget grows to about $8,375. That’s your real monthly cost at retirement — and that’s the number your retirement target should be based on.

Missing this step is one of the most common and most costly mistakes in retirement planning. A plan that looks solid on paper in today’s dollars can be significantly underfunded when you actually need it.

What About Social Security?

Social Security changes your number — but probably less than you think, and less reliably than most planners assume.

If you expect to receive $1,500 a month from Social Security, that reduces the amount you personally need your portfolio to generate. In effect, it lowers your effective monthly expense gap. Instead of needing your portfolio to cover $4,000 a month, you only need it to cover $2,500 — which means your target drops from $1,200,000 to $750,000.

That’s a meaningful difference. However, there are good reasons to be careful about relying too heavily on this:

Social Security’s future benefit levels are genuinely uncertain over a 30-year horizon. Claiming age matters significantly — claiming at 62 versus 70 can result in benefits that differ by more than 75%. And for anyone pursuing early retirement, Social Security doesn’t even begin until your mid-60s at the earliest, which means you need your portfolio to cover a gap period regardless.

A conservative approach is to calculate your full retirement target without Social Security, then treat any benefits as a buffer that extends your portfolio’s runway.

Does the 4% Rule Still Work?

Reasonable people disagree on this, and it’s worth knowing where the disagreement comes from.

The 4% rule originated from research in the early 1990s looking at historical US market data. It found that portfolios invested in a mix of stocks and bonds could sustain a 4% annual withdrawal for at least 30 years across virtually every historical 30-year period studied.

The concern today is that the future may not look like the past. Lower expected bond returns, higher valuations, and longer life expectancies all introduce legitimate uncertainty. Some researchers now suggest 3% to 3.5% as a more conservative figure for people retiring early with a longer time horizon.

What this means practically: if you’re planning for early retirement and a long runway, using a 3.5% withdrawal rate instead of 4% adds a margin of safety. It also raises your target — a 3.5% withdrawal rate means multiplying annual expenses by about 28.5 instead of 25.

Withdrawal Rate	Monthly Expenses	Target
5.0%	$4,000	$960,000
4.0%	$4,000	$1,200,000
3.5%	$4,000	$1,371,000
3.0%	$4,000	$1,600,000

Putting It Together: Your Actual Number

Here’s the honest process for calculating your retirement number:

Step 1 — Estimate monthly expenses in retirement. Not your current expenses — your retirement expenses. Think about what your life actually costs when you’re not working. Some costs go down (commuting, work clothes, lunch out). Some go up (healthcare, travel, hobbies). A reasonable estimate for most people is somewhere between 70% and 90% of their current spending.

Step 2 — Apply the 4% rule. Multiply annual expenses by 25. This is your baseline target in today’s dollars.

Step 3 — Adjust for inflation. Multiply by (1 + inflation rate) raised to the power of years until retirement. Use 3% as a default if you’re unsure. This converts your target to future dollars — which is the actual amount you’ll need your portfolio to reach.

Step 4 — Decide on your withdrawal rate. If you’re planning for 30+ years of retirement, consider using 3.5% instead of 4% for a margin of safety.

Step 5 — Factor in other income. If you’ll have Social Security, a pension, or rental income, subtract that monthly amount from your expenses before applying the formula.

A Worked Example

Let’s walk through it with real numbers.

Sarah is 35 and plans to retire at 60 — 25 years away. She estimates she’ll spend $5,000 a month in retirement. She expects 3% annual inflation. She’ll use a 4% withdrawal rate.

Baseline target: $5,000 × 12 ÷ 4% = $1,500,000 in today’s dollars

Inflation adjustment: $5,000 × (1.03)^25 = $10,469 per month at retirement

Inflation-adjusted target: $10,469 × 12 ÷ 4% = $3,140,700

That’s more than double the baseline. Not because Sarah’s lifestyle changed, but because the same lifestyle costs more in 25 years.

If Sarah plans to receive $1,200 a month from Social Security at 67, she could factor that in and reduce her portfolio target accordingly — but only for the years after 67. She still needs her portfolio to cover the full gap from 60 to 67.

The Most Important Thing

Your retirement number is not a fixed destination — it’s a calculation you revisit as your life changes. Your spending will shift. Your expected return on investments will be refined over time. Inflation will do what it does.

What matters is that you have a number based on your actual life, not someone else’s average. Run your own math. Adjust your withdrawal rate to match your risk tolerance. And account for inflation — because that’s the one variable that most people skip and most regret.

The calculator below does all of this in one place. Enter your monthly expenses, set your inflation rate, and see your inflation-adjusted retirement target in real time.