There are two ways to adjust your FIRE number for inflation, and they give the same answer if you’re consistent. You can keep your target in today’s dollars and project growth with a real (after-inflation) return, or inflate your spending to the year you retire and project growth with a nominal return. The first is simpler, and it’s what most FIRE planners use.
The mistake to avoid is mixing them: a today’s-dollars target with a nominal return makes you look years closer than you are.
Why inflation matters so much for FIRE #
At 3% a year, inflation roughly halves the buying power of a dollar in about 24 years. Here’s what $100,000 buys, in today’s terms, after:
| Years | Buying power of $100,000 at 3% inflation |
|---|---|
| 10 | about $74,400 |
| 20 | about $55,400 |
| 30 | about $41,200 |
Say you spend $60,000 a year and set a FIRE number of $1.5 million. If you reach that $1.5 million in 20 years without adjusting for inflation, a 4% withdrawal gives you $60,000 of future dollars, worth only about $33,000 of today’s spending. You’d be retiring on little more than half the lifestyle you planned.
Method 1: keep the target in today’s dollars #
This is the “real return” method.
- Set your target in today’s dollars. $80,000 of spending x 25 = $2,000,000.
- Use a real return for growth. If you expect about 10% a year before inflation and inflation runs about 3%, your real return is roughly 7% (6.8% if you calculate it precisely).
- Project your timeline with that real return. When your projection hits $2 million, you have $2 million of today’s buying power.
Pros: your target stays a number you understand, and you don’t recalculate it every year.
Cons: your actual account balances will run ahead of your model, since real accounts grow in nominal dollars. That’s expected, not a mistake.
Many planners use a real return of 5% to 7% for stocks rather than the full historical figure, to leave room for weaker decades. Our guide to what S&P 500 return to use for retirement planning covers the choice.
Retire Goals makes this method easy: its calculators have an optional inflation toggle that restates every projection in today’s dollars, so you can switch between the balance you’ll see in your account and what it will actually buy.
Method 2: inflate your target to future dollars #
This is the “nominal target” method.
- Inflate your spending to your retirement year. $60,000 of spending, 15 years away, at 3% inflation: $60,000 x 1.03^15 = about $93,478.
- Multiply by 25. $93,478 x 25 = about $2,336,950.
- Use a nominal return, such as 10%, for growth.
Pros: your milestones match the balances you see when you log into your accounts.
Cons: big future-dollar targets feel abstract, and you have to recalculate if your timeline changes.
| Method 1: real return | Method 2: nominal target | |
|---|---|---|
| Target is in | Today’s dollars | Future dollars |
| Growth rate | Real (about 5% to 7%) | Nominal (about 8% to 10%) |
| Recalculating needed | Rarely | Whenever your timeline moves |
| Matches account balances | No, balances run ahead | Yes |
Which inflation rate should you use? #
The Federal Reserve targets 2% inflation, and long-run U.S. inflation has averaged close to 3%. Most planners use 2.5% to 3%. Recent years are a reminder that it can run hotter; Social Security’s cost-of-living adjustment for 2026 was 2.8%, per the Social Security Administration’s 2026 notice.
Your personal inflation rate may differ from the national one:
- Housing: a fixed-rate mortgage locks in most of your housing cost, and paying it off removes it. Renters face rent increases that can outpace general inflation.
- Health care: it has tended to rise faster than overall prices. Some planners use 4% to 5% for the health care part of their budget.
- Lifestyle creep: spending more as you earn more isn’t inflation, but it raises your FIRE number just the same. Track it separately so you can tell which is which.
How inflation works after you retire #
The 4% rule already builds inflation in for the retirement phase: you withdraw 4% in year one, then raise that dollar amount each year by the previous year’s inflation. What it doesn’t do is adjust your target before retirement. That’s your job, using either method above.
Once retired, you have a few options if inflation spikes:
- Guardrails: trim discretionary spending in years when inflation is high and markets are down.
- A flexible withdrawal method like variable percentage withdrawal, which adjusts to your portfolio’s value.
- Inflation-protected income: Social Security benefits are adjusted each year, and Treasury Inflation-Protected Securities (TIPS) adjust their principal with inflation.
Before you retire, test the drawdown. The Will My Money Last calculator in Retire Goals raises your withdrawal each year for inflation and shows how many years your portfolio covers, plus the spending that would make it last 30.
Keep your number current #
Once a year, total your actual spending for the past 12 months and use that as your new baseline. That one step captures both real inflation and any lifestyle creep. If you’re chasing Coast FIRE, rerun that number too, with a conservative real return; see how to calculate your Coast FIRE number.
Frequently asked questions #
Does the 4% rule already account for inflation? #
Only after you retire. The rule assumes you raise withdrawals with inflation each year. Your target before retirement still needs adjusting, either by using a real return or by inflating the target to future dollars.
Should I use 2%, 3% or 4% for inflation? #
3% is a common, reasonably cautious choice for long-term planning. If you want extra margin, 3.5% or 4% builds a cushion, at the cost of a bigger target or a later date.
How do I adjust dividend income goals for inflation? #
Look at dividend growth. To keep your buying power, your portfolio’s dividends need to rise at least as fast as inflation. Funds focused on companies with long records of raising payouts are one way to aim for that.
What if inflation spikes right before I retire? #
Your spending, and so your FIRE number, jumps in dollar terms. You can delay a year or two, cover part of your spending with part-time work for a while, or start with a lower withdrawal rate such as 3.25% to 3.5%.