How Much Do I Need to Retire? Find Your Number in 10 Minutes

Why 'how much do I need to retire' is the wrong question to fear

If you've ever typed 'how much do I need to retire' into a search bar and closed the tab in panic, you're not alone. Retirement number anxiety is one of the most common money fears, and it usually comes from thinking the answer requires a financial planning degree. It doesn't. Your retirement number—the total savings you need to cover your future expenses without running out of money—can be estimated in about 10 minutes using a few well-tested rules of thumb. This guide walks through exactly how to calculate your retirement number, why the calculation matters more than your current bank balance, and how to close the gap once you know where you stand.

The 25x rule: the fastest way to estimate your retirement number

The most widely used shortcut for calculating your retirement number is the 25x rule, which comes from the 4% safe withdrawal rate research. Here's how it works: take your estimated annual expenses in retirement and multiply that number by 25. If you expect to spend $50,000 per year in retirement, your retirement number is $1,250,000. If you expect to spend $40,000 per year, your number drops to $1,000,000. The logic behind the 25x rule is that withdrawing 4% of your portfolio annually has historically allowed retirement savings to last 30 years or more, even accounting for market downturns. It's not perfect, but it's an excellent starting point that takes 30 seconds to calculate once you know your expected annual spending.

Step 1: Estimate your realistic annual retirement expenses

Before you can calculate your retirement number, you need a realistic picture of what retirement will actually cost you. Start with your current annual spending and adjust for what changes in retirement. Some costs go down: no more commuting, no more retirement contributions, and often a paid-off mortgage. Other costs go up: healthcare premiums before Medicare eligibility, travel, and hobbies you'll finally have time for. A common rule of thumb is that retirees spend 70% to 80% of their pre-retirement income, but this varies widely based on lifestyle and whether your mortgage is paid off. The most accurate method is to track your actual monthly spending for a few months and project forward, adjusting categories up or down based on how your life will change.

Step 2: Account for Social Security and other guaranteed income

Your retirement number isn't just about what your savings need to cover—it's about the gap between your expenses and your guaranteed income sources like Social Security, pensions, or rental income. If you expect $30,000 per year in Social Security benefits and your annual expenses will be $60,000, your savings only need to cover the $30,000 gap, not the full $60,000. Using the 25x rule on that gap gives you a retirement number of $750,000 instead of $1,500,000. You can find your estimated Social Security benefit by creating a free account at ssa.gov and checking your statement. This single step often cuts a retirement number nearly in half, which is why skipping it leads to wildly inflated—and discouraging—estimates.

Step 3: Calculate the gap between your number and your current savings

Once you know your retirement number, compare it to your current total retirement savings across all accounts—401(k)s, IRAs, brokerage accounts, and any other investments earmarked for retirement. The difference between your number and your current total is your savings gap. If your retirement number is $900,000 and you currently have $200,000 saved, your gap is $700,000. This isn't meant to be discouraging—it's meant to be actionable. Knowing the exact gap lets you calculate how much you need to save monthly to close it, using your investment timeline and an assumed annual return (7% is a commonly used long-term average for a diversified stock and bond portfolio).

Step 4: Use compounding to work backward from your target date

The power of compounding means the earlier you start, the less you need to save each month to hit your number. For a simplified example starting from zero, reaching $700,000 in 30 years at a hypothetical 7% annual return compounded monthly requires about $574 deposited at the end of each month; over 15 years it requires about $2,208 per month. If you already have savings, project their growth separately and subtract that projected amount from your target before calculating new contributions. These figures ignore taxes, fees, and inflation; returns are not guaranteed. This is why financial advisors emphasize starting early: every year you delay significantly increases the monthly savings burden required to hit the same retirement number. Running these numbers with your actual timeline turns an abstract goal into a concrete monthly savings target.

Adjusting your number for lifestyle, longevity, and inflation

The basic 25x calculation is a starting point, not a final answer. A few adjustments make your retirement number more accurate to your actual life. If you plan to retire early (before 60), you may want a more conservative withdrawal rate than 4%, since your money needs to last longer—some early retirees use a 3% to 3.5% withdrawal rate instead, which means multiplying expenses by 28 to 33 rather than 25. If you have a family history of longevity or want extra safety margin, err toward the higher multiplier. Also remember that inflation erodes purchasing power over time, so your retirement number should be calculated in today's dollars, and your savings plan should assume your investments need to outpace inflation, not just grow in nominal terms.

Common retirement number mistakes that throw off your math

A few mistakes commonly distort retirement number calculations. The first is using your current income instead of your projected retirement expenses—these are often very different numbers. The second is forgetting healthcare costs, which tend to rise significantly with age and can be a major expense before Medicare kicks in at 65. The third is ignoring taxes: withdrawals from traditional 401(k)s and IRAs are taxed as ordinary income, so your retirement number may need to be higher to net your target after-tax spending amount. The fourth is failing to update the calculation over time—your retirement number should be revisited every year or two as your income, expenses, and savings evolve.

What to do once you know your retirement number

Calculating your retirement number is the easy part—the real value comes from what you do with it. Once you know your target and your current gap, you can set a concrete monthly savings goal, choose an appropriate investment allocation for your timeline, and track your progress annually to stay on course. Many people find that seeing the number itself, rather than avoiding it, removes a huge amount of retirement anxiety. Even if your number feels far away today, breaking it into a monthly savings target and a clear timeline turns retirement from an abstract worry into a plan you can actually execute.

Turn your number into a plan in the next 10 minutes

Now that you know your retirement number, the fastest way to put it into action is with a tool that tracks your progress automatically instead of a napkin calculation you'll lose track of. The Retirement Planner Bundle includes a built-in calculator that runs the 25x rule, Social Security offset, and monthly savings targets for you, alongside a workbook to log your accounts and a visual map to track your progress year over year. Spend the next 10 minutes plugging in your numbers, and you'll walk away with a clear, personalized retirement target instead of a vague sense of worry.