FIRE (Financial Independence, Retire Early) has become a mainstream goal. The math is straightforward: save 25 times your annual expenses, invest it in low-cost index funds, and you can live off a 4% annual withdrawal indefinitely. The hard part is the savings rate required to get there in your 40s or earlier.

For most Americans, the biggest barrier is a structural one: child costs. Remove that barrier, and the timeline changes dramatically.

What FILE means

FILE stands for Financial Independence, Live Early. It resonates with the childfree community because it acknowledges a specific structural advantage: without the $16,857-per-year average cost of raising a child, savings rates can be dramatically higher from the beginning of your career, not just after the kids leave the house.

The difference is about when you reach the number, not just the amount. Reaching it ten years earlier isn't a marginal improvement. Ten more years of work, compounding in the wrong direction, is a decade of your finite life.

The math on the head start

Consider two households, otherwise identical:

  • Household A (DINK): Combined income $120,000, monthly savings $3,000 ($36,000/year), starting at 28.
  • Household B (with one child): Same income, but $16,857/year goes to child costs. Savings drops to roughly $1,600/month ($19,000/year) for 18 years, then returns to $3,000/month.

At a 7% annual return, Household A reaches $1 million (a rough FI threshold for a $40,000/year lifestyle) at around age 47. Household B reaches the same milestone at around age 54. Seven years of difference, from the same income, same savings discipline, same investments.

And $1 million is a conservative FI number. If your target is $1.5 million or $2 million, the gap widens because Household A is compounding a larger base during those early years.

The DINK Wealth Projection calculator on this site lets you run your own numbers. Plug in your monthly savings, current age, and target retirement age and it shows you the divergence in real time.

Why the early years matter most

The FILE advantage is so large because of when the savings happen. A dollar invested at 28 compounds for 37 years before a standard retirement age of 65. At 7%, that dollar becomes $12.

A dollar that went to child costs at 28 doesn't compound at all. It's gone.

Household B's savings shortfall during the child-rearing years (18 years × ~$17,000/year shortfall = ~$306,000 in uninvested money) doesn't mean $306,000 less at retirement. It means roughly $1.2 million less, because that money never compounded.

The real figure is the $1 million+ in lost compounding, not just the $303,000 in avoided expenses.

What a realistic FILE path looks like

For a childfree household earning a combined $120,000-$180,000, a practical FILE plan looks something like this:

Savings rate target: 30-40% of gross income. Aggressive but achievable without children. It means living on roughly $70,000-$100,000 on a $150,000 income, which is a comfortable life in most U.S. cities.

Accounts to fill in order:

  1. 401(k)s to the employer match (free money, never skip it)
  2. HSA if eligible ($4,300 individual / $8,550 family in 2025, triple tax advantage)
  3. Roth IRA ($7,000 each in 2025, if income-eligible)
  4. 401(k)s to the full $23,000 each limit
  5. Taxable brokerage for everything above

Asset allocation: A simple two-fund or three-fund portfolio (total U.S. market plus international, possibly with bonds as you approach your target) is all you need. The edge in FILE comes from savings rate and time, not from picking the right funds.

The 4% rule and flexibility: If you retire at 45 with $1.5 million, you can withdraw $60,000/year indefinitely under historical scenarios. That number holds up over 50+ year retirement periods in most backtesting. If you want a larger buffer, work a few extra years or build in part-time income during your 50s.

The tax and healthcare gap

Early retirement has two structural challenges that FIRE discussions often gloss over: healthcare and the gap years before Social Security.

Healthcare: If you leave a W-2 job before 65 (Medicare eligibility), you're on your own for health insurance. ACA marketplace plans are the primary option, and income-based subsidies can significantly reduce the cost if your taxable income is managed carefully, which it can be since capital gains and Roth conversions give you levers to control your tax bracket.

Social Security: Retiring at 45 means 20+ fewer years of contributions. Your eventual Social Security benefit will be lower than if you'd worked to 62 or 67. For most early retirees this is acceptable because the investment portfolio more than compensates, but it's worth factoring into your number.

The real point

FILE requires high savings rates, index-fund discipline, and a long time horizon. But it avoids the uphill battle it becomes for households with children, where the savings rate is structurally suppressed during exactly the years when compounding matters most.

The childfree wealth advantage is large, measurable, and actionable. The question is whether you're doing anything with it.

Start with your number. Use the DINK Wealth Projection calculator to see when you can realistically hit financial independence at your current savings rate. Then decide if you want to get there faster.

Further reading