If you’ve typed how much do I need to retire into Google, you’ve probably seen the same answer recycled a hundred different ways: multiply your annual expenses by 25. Save that amount. Done.
That’s the 4% rule. And while it’s a useful starting framework, using it as your entire retirement plan is like using a weather app to navigate a hurricane. It gives you a number. It doesn’t tell you whether that number will actually keep you alive financially for 25 to 30 years.
I’ve watched people retire with what looked like enough — and run out of money in their 70s. I’ve also watched people delay retirement for five extra years chasing an arbitrary number they didn’t actually need. Both situations are painful. Both are avoidable.
So let’s talk about how to find your real retirement number. Not the one a calculator spits out in 30 seconds. The one that actually accounts for your life.
Why the 25x Rule Isn’t Enough
The 25x rule comes from the famous Trinity Study, which looked at historical portfolio survival rates over 30-year periods. The finding: if you withdraw 4% of your portfolio in year one and adjust for inflation each year after, your portfolio has historically survived 95% of 30-year periods.
That’s solid research. But notice what it assumes: a 30-year retirement. A portfolio of 50-75% stocks. No major sequence of returns risk in the first decade. Consistent inflation at historical averages. No catastrophic healthcare event. And no changes to Social Security.
You are not a historical average. You’re a specific person with a specific health history, a specific spending pattern, a specific Social Security timeline, and a specific sense of what a good retirement actually looks like.
The 25x rule is a starting point. Your job is to pressure-test it against reality.
Step 1: Know What You Actually Spend (Not What You Think You Spend)
Before you can calculate how much you need to retire, you need an honest picture of what you spend today — and what you expect to spend in retirement.
Most people underestimate their retirement spending by 20 to 30 percent. Here’s why: they forget about the categories that explode in retirement.
Healthcare is the big one. If you retire before 65 and lose employer-sponsored health coverage, you could be spending $800 to $1,500 per month on premiums alone — before copays, deductibles, and prescriptions. A serious health event in your late 60s can cost tens of thousands of dollars even with good insurance. Long-term care — which roughly 70% of people over 65 will need at some point — averages $54,000 a year for home health aide services and over $90,000 a year for a private nursing home room.
Travel is another one people undercount. You finally have time to go to all the places you put off for 40 years. That’s real money. So are gifts for grandchildren, home repairs that accumulate when you stop deferring maintenance, and the simple reality that you now have 168 hours per week to fill instead of 40.
A more honest framework: plan for 80-90% of your pre-retirement income in the early years of retirement, not 70% like most rules of thumb suggest. That number tends to drop in your mid-70s as activity decreases — but it often spikes again in your late 70s and 80s as healthcare costs rise.
Step 2: Build the Right Formula for Your Situation
Here is a more complete way to think about your retirement number:
Your Retirement Number = (Annual Spending − Guaranteed Income) × Your Multiplier
Let’s break that down.
Annual Spending is your honest, inflated, healthcare-included retirement budget.
Guaranteed Income is what you’ll receive regardless of market performance — Social Security, a pension, an annuity. This is money you don’t need your portfolio to generate.
Your Multiplier is determined by your planned withdrawal rate and your retirement timeline. The standard 4% rule gives you a 25x multiplier. But if you retire at 55 and need the money to last 40 years, consider a 3.3% withdrawal rate — which pushes your multiplier to 30x. If you retire at 67 with a shorter planning horizon, 4.5% may be defensible, giving you a 22x multiplier.
Here’s a simple example. Meet Sandra, 58, a healthcare administrator from Ohio. She spends $6,800 a month today. She expects to spend $7,200 a month in retirement — she’s factoring in travel and higher healthcare costs. That’s $86,400 a year.
Her Social Security benefit at 67 will be $2,100 a month — $25,200 a year. Her husband will receive $1,600 a month — $19,200 a year. Combined guaranteed income: $44,400.
Her annual portfolio need: $86,400 − $44,400 = $42,000. At a 4% withdrawal rate, her retirement number is $42,000 × 25 = $1,050,000. Not $2.16 million (what 25x her total spending would suggest). $1.05 million.
The difference is enormous. And most calculators don’t do this math.
The Social Security Wild Card
Social Security deserves its own section because the timing decision alone can change your retirement number by hundreds of thousands of dollars.
You can claim as early as 62, at your full retirement age (currently 67 for most people), or as late as 70. Every year you delay past your full retirement age, your benefit grows by 8%. That’s a guaranteed, inflation-adjusted 8% return — better than most investments you can make.
The break-even math: if your full retirement benefit is $2,000 a month at 67, waiting until 70 gives you $2,480 a month. If you live past your early 80s, waiting wins. If your health history suggests you won’t, claiming earlier may be the right call.
The point is: your Social Security timing decision directly affects how large your portfolio needs to be. Get this wrong and you’re either leaving tens of thousands on the table or withdrawing from your portfolio at a rate it can’t sustain.
What If You’re Behind? Here’s What Actually Moves the Needle
Let’s be honest about something. If you’re reading this in your 50s and your savings feel far short of what you need, that’s where most Americans actually are. A 2025 survey found the average retirement savings for people aged 55-64 is around $185,000. The median — which better reflects the typical person — is closer to $87,000.
If those numbers describe you, the answer isn’t panic. It’s prioritization. Here’s what actually moves the needle at this stage:
Maximize catch-up contributions. In 2026, if you’re 60-63, you can put up to $35,750 into your 401(k) — the highest contribution window in your working life. Use it. Every dollar you contribute now has 5-10 years of compound growth before you need it.
Delay retirement by even two years. Working until 67 instead of 65 doesn’t just add two more years of savings — it also shortens the period your portfolio needs to support you, increases your Social Security benefit, and reduces the years of healthcare costs you’ll face without employer coverage.
Right-size your lifestyle now, not at retirement. The biggest lever most people have isn’t their investment return — it’s the gap between what they earn and what they spend. Closing that gap by $500 a month for 10 years is worth over $75,000 at a 5% return.
Reconsider what retirement actually looks like. Full stop retirement at 65 is not the only option. Semi-retirement — part-time consulting, freelance work, a small business — can reduce portfolio withdrawals significantly in the early years when sequence of returns risk is highest.
Your Actual Next Step
The most dangerous thing you can do right now is nothing. Whether you’re on track or behind, the clarity that comes from running your actual numbers — not a generic calculator — is what makes the difference between a retirement that works and one that doesn’t.
Run your personalized retirement assessment now. It takes less than five minutes and gives you a starting picture of where you actually stand — including your specific retirement gap and the contribution levels that close it.
Your number is out there. Let’s go find it.
