Skip to main content
/
financial independenceFIREFI numbersavings rateretirement4% ruleinvesting
//// Financial · Independence & FIRE

Financial Independence: How Close Are You?

Your FI number is annual expenses times 25. The variable that changes everything is your savings rate. See the math — and the timeline.

Where this fits

📈 Investing & WealthCash FlowRetirement Plan

This tool lives inside Cash Flow + Retirement Plan and is most useful for people making this kind of decision.

401(k) Limit 2024$23,000
Roth IRA Limit$7,000
S&P 500 Avg Return~10%/yr
Your FI Number
$1,250,000
Annual expenses × 25 (4% rule)
Years to FI
28 years
At your current savings rate
FI Age
Age 53
Traditional retirement range

Your Numbers

What If You Saved $200/Month More?

At your current savings rate you're FI at age 53. If you save $200/month more, you'd be FI at age 51 — that's 2 years earlier.

$200/month = $2,400/year in additional savings — 2 fewer years of working.

Progress to FI

1%

You're 1% of the way to your FI Number. Gap remaining: $1,240,000.

Savings Rate Impact

Your savings rate is the most powerful lever you have. Here's how each rate changes your timeline (same starting assets and return).

Savings RateYears to FIFI Age
10%37Age 62
20%← you28Age 53
30%24Age 49
40%20Age 45
50%18Age 43
60%16Age 41
70%15Age 40
1

FI Number (4% rule)

FI Number = Annual Expenses × 25

$50,000 × 25

= $1,250,000

Based on the 4% safe withdrawal rate — a portfolio 25× your annual expenses can sustain 30+ years of withdrawals with high historical probability.

2

Current savings rate

Savings Rate = Annual Savings ÷ Annual Income × 100

$15,000 ÷ $75,000 × 100

= 20.0%

3

Gap to FI

Gap = FI Number − Current Invested Assets

$1,250,000 − $10,000

= $1,240,000

4

Compound growth formula

FV = P×(1+r)^n + PMT×((1+r)^n − 1)/r

P=$10,000, PMT=$15,000/yr, r=7%

= Used to find n where FV ≥ FI Number

Iterates year by year until the portfolio reaches the FI Number. Uses real (inflation-adjusted) return so all values are in today's dollars.

5

Years to FI

Solve for n: FV(n) ≥ FI Number

Start: $10,000, target: $1,250,000

= 28 years

6

FI age

FI Age = Current Age + Years to FI

25 + 28

= Age 53

7

Savings rate sensitivity

Higher savings rate → fewer years working

At 20% rate: 28 yrs | At 50% rate: 18 yrs

= See table below for all rates

Savings rate is the single biggest lever. Going from 20% to 40% can cut your working years nearly in half.

Key insight

The 4% rule and compound growth math are the foundation. But your savings rate is the variable that actually changes everything — higher savings both grows the portfolio faster AND lowers the FI target.

#ShowYourWork

You might also need

Financial Independence Number Calculator

Calculate your FI number at three expense tiers: essential-only, full lifestyle, and dream life. See years to each tier at your savings rate, your Coast FI number, and the monthly savings needed to retire by your target age.

Try it

Retirement Savings Calculator

Find out if you're on track to retire comfortably. See your projected balance, inflation-adjusted income, and exactly how much more to save each month to close any gap.

Try it

Savings Rate Calculator

Calculate your savings rate and see how it affects your path to financial independence. FI number, years to FI, projected retirement balance, and a sensitivity table across 5–70% savings rates.

Try it

💰More Financial tools

Roth vs Traditional IRA→401(k) Contribution Optimizer→Contractor Retirement Catch-Up Calculator→Time Value of Money Calculator→All Financial tools