Your financial independence number is the amount of invested money that can cover your living costs so that working becomes optional. It’s often shortened to your FI number.
Most retirement advice gives you a single figure, usually $1 million, and stops there. That figure means very little until you know what you actually spend. Your number isn’t tied to a birthday. It depends on your spending, your other income, and how long the money has to last.
This guide shows how to calculate your financial independence number step by step. It also covers what pushes it up or down: healthcare, taxes, Social Security timing, and retirement age.
What Is a Financial Independence Number?
A financial independence number is the portfolio size that can pay for your yearly expenses through regular withdrawals. Once you reach it, your investments can, in theory, fund your lifestyle without a paycheck.
Two points are worth keeping in mind:
- It’s based on spending, not income. Someone earning $150,000 and spending $110,000 needs a much larger number than someone earning $80,000 and spending $45,000.
- It’s an estimate. Markets, inflation, and health costs change, so treat your target as a range rather than a promise.
The Basic Financial Independence Number Formula
The core formula is simple:
FI number = annual spending ÷ withdrawal rate
Most people use a 4% withdrawal rate, which works out to multiplying annual spending by 25. At 4%:
- $40,000 a year of spending points to about $1,000,000
- $60,000 a year points to about $1,500,000
- $90,000 a year points to about $2,250,000
Where the 4% Rule Comes From (and Why It’s Only a Starting Point)
The 4% rule traces back to research by William Bengen. You withdraw 4% of your portfolio in the first year of retirement, then raise that dollar amount with inflation each year, with the goal of making the money last about 30 years.
It’s a guideline, not a guarantee, and it’s the assumption behind most financial independence number estimates you’ll see online. Morningstar’s 2026 retirement income research puts the highest safe starting withdrawal rate at 3.9%, assuming a 30-year retirement and a 90% chance of money remaining at the end. The same research notes that retirees who take a flexible approach to spending can increase their spending power. That could mean trimming withdrawals after a bad market year.
The length of retirement also matters. A longer retirement generally calls for a lower starting rate, because the money has to last more years.
Here is how much the rate changes the result. On $60,000 of yearly spending, 4% puts your financial independence number at $1.5 million. A more cautious 3.5% gives you about $1.71 million. That’s roughly $214,000 more, from one assumption.
How to Calculate Your Financial Independence Number Step by Step
1. Estimate your annual spending in retirement. Start with what you spend now. Pull 6 to 12 months of bank and card statements and total them. Then adjust. Commuting and retirement contributions may drop, while healthcare and travel may rise.
Housing deserves extra attention. According to the Bureau of Labor Statistics, housing made up 33.4% of average household spending in 2024. A paid-off home can change your number dramatically.
2. Subtract guaranteed income. This includes Social Security, a pension, or an annuity. You can see your personal Social Security estimate in your my Social Security account. For context, the average retired worker’s benefit was estimated at about $2,071 a month in 2026. Yours depends on your earnings history and the age you claim.
3. Choose a withdrawal rate. Use 4% as a middle assumption. Go lower if you plan a very long retirement or want extra margin.
4. Divide the gap by your rate. The result is your financial independence number.
Worked Example: Retiring at 67
These figures are hypothetical:
- Annual spending: $60,000, including estimated taxes and healthcare
- Estimated Social Security: $24,000 a year ($2,000 a month)
- Gap to cover from savings: $36,000
- At 4%: $36,000 × 25 = $900,000
- At 3.9%: about $923,000
Social Security covers 40% of spending here, so the portfolio only needs to cover the rest. The financial independence number for this person is roughly $900,000 to $925,000.
Worked Example: Retiring at 50
Same $60,000 of spending, but very different math:
- Social Security can’t start until age 62 at the earliest, and claiming that early permanently reduces it.
- Medicare doesn’t start until 65, so you have to arrange your own health coverage until then.
- The money may need to last 40 years or more.
Using a cautious 3.5% rate, $60,000 ÷ 0.035 is about $1.71 million. That figure ignores future Social Security, so it leans conservative. A detailed projection could land lower, but it’s a sensible starting target.
Same spending, two very different numbers. That’s why a single “retirement number” you see online is rarely useful.
What Moves Your Financial Independence Number the Most
Your Spending
Every $1,000 a month you cut from your budget lowers your financial independence number by $300,000 at a 4% rate ($12,000 × 25). Even $100 a month is worth $30,000.
Small habits matter here. A simple pause like the 24-hour rule for spending can trim impulse purchases. That helps twice: you invest more today, and you need a smaller number later.
When You Claim Social Security
For anyone born in 1960 or later, full retirement age is 67. Claiming at 62 permanently cuts the monthly benefit by 30% for that group, while waiting past full retirement age adds 8% per year, up to 124% of the full benefit at 70. The Social Security Administration publishes the reduction schedule for each birth year.
Using the earlier example, a $2,000 monthly benefit at 67 becomes $1,400 at 62 or $2,480 at 70. A higher guaranteed benefit means a lower financial independence number, and the reverse is also true.
Benefits also get yearly cost-of-living increases. The 2026 adjustment was 2.8%, and the increase has averaged about 3.1% over the last decade, according to the SSA.
Healthcare
Healthcare is the line item people underestimate most when they work out their financial independence number. Fidelity estimates that a 65-year-old retiring in 2026 may spend an average of $185,500 on health care and medical costs throughout retirement. That estimate assumes traditional Medicare and no employer retiree coverage, and it leaves out long-term care.
The premiums alone add up. The standard Medicare Part B premium is $202.90 a month in 2026, according to CMS.
Medicare generally starts at 65. If you retire earlier, you’ll need coverage through a spouse’s plan, COBRA, or the Health Insurance Marketplace. Budget for it as its own line.
Taxes
Withdrawals from traditional 401(k)s and IRAs are generally taxed as ordinary income. Qualified Roth withdrawals generally aren’t. Depending on your total income, part of your Social Security benefit can be taxable too. The IRS has an overview of retirement plan rules.
Make sure your spending figure includes taxes. Otherwise your financial independence number will come up short. Two people with the same $60,000 budget can need different portfolio sizes depending on how their money is split between account types.
Debt
Debt payments are part of your spending, so eliminating them shrinks your target. High-interest credit card balances are the most expensive kind. If you pay your statement balance in full each month, the credit card grace period generally means you avoid interest on new purchases.
If you pay off a balance and notice your credit score dropped after paying off the account, that usually isn’t a reason to hold on to debt you’re trying to eliminate.
Getting to Your Money Before 59½
If you plan to retire early, access matters as much as the size of your financial independence number. Most withdrawals from 401(k)s and IRAs before age 59½ face an extra 10% tax on top of regular income tax, unless an exception applies. Two well-known exceptions are leaving an employer during or after the year you turn 55, and taking a series of substantially equal periodic payments. The IRS explains these exceptions in detail.
Both come with strict rules, so talk to a tax professional before relying on either one. Many early retirees also build a taxable brokerage account or cash reserve to cover the first years without touching retirement accounts.
How to Close the Gap
Once you know your financial independence number, compare it with what you have today. Then you have three levers: save more, spend less, or adjust the timeline.
Tax-advantaged accounts are the best place to start. For 2026, the IRS raised the 401(k) contribution limit to $24,500 and the IRA limit to $7,500. If your employer offers a match, capture all of it first.
Then revisit your number once a year. Spending, tax rules, and market conditions all shift, and a target you set five years ago may not fit today.
Common Mistakes When Calculating Your Financial Independence Number
- Using income instead of spending. The formula runs on what you spend, not what you earn.
- Treating 4% as a guarantee. It’s a research-based starting point that depends on market conditions and time horizon.
- Leaving out healthcare and taxes. Both can be large and are easy to forget.
- Assuming a Social Security amount without checking. Your statement and claiming age decide the real figure.
- Setting the number once and forgetting it. Recalculate at least yearly.
Frequently Asked Questions
Is $1 million enough to retire?
At a 4% rate, $1 million supports about $40,000 a year. At 3.9%, it’s about $39,000. Whether that’s enough depends on your spending, Social Security, healthcare costs, taxes, and how long you need the money to last.
Should I include Social Security in my financial independence number?
Many people calculate it both ways. A number without Social Security is more conservative. A number that includes it is more realistic if you expect to claim. Check your estimate in your Social Security account before counting on it.
How often should I recalculate?
At least once a year, and after any major change such as a job switch, a move, or a big shift in your expenses.
Final Thoughts
Your financial independence number isn’t a magic figure. It’s your annual spending, minus guaranteed income, divided by a withdrawal rate you’re comfortable with. Small changes to any of those inputs can move the result by hundreds of thousands of dollars.
Start with your real spending, check your Social Security estimate, and add healthcare and taxes to the calculation. Then run the math at two or three withdrawal rates to see the range for your own financial independence number.
This article is for educational purposes only and isn’t personalized financial, tax, or legal advice. For decisions specific to your situation, consider speaking with a qualified financial professional or tax advisor.
