CalcAtlas

Fat FIRE for a Tech Engineer

A high-spending Financial Independence plan for a 35-year-old engineer targeting a $120,000 real annual lifestyle by age 50, with a 3.5% withdrawal rate. A pre-filled FIRE calculator scenario.

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Last updated: 2026-08-12

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Your assumptions

$6,000
$0$10,000

Results

Behind your target age

FIRE number

$3,428,571

Annual spending ÷ withdrawal rate, in today's money.

Financially independent at

64 yrs

Time to independence: 29 years

Portfolio at target age

$2,782,236

In today's money: $1,921,038

Investment growth

$6,137,155

80% of the final portfolio comes from compounding

Coverage of the FIRE number56%

Total contributed

$1,539,122

Sustainable annual income

$67,236

Monthly saving needed to hit the target on time

$14,187

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CalcAtlascalc.100ideas.netFat FIRE for a Tech EngineerFIRE number$3,428,571Financially independent at64 yrsSustainable annual income$67,236calc.100ideas.net

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Portfolio projection

Year by year

AgeBalanceReal value
36$288,282$281,251
37$384,972$366,422
38$490,725$455,687
39$606,246$549,229
40$732,288$647,236
41$869,661$749,906
42$1,019,233$857,446
43$1,181,937$970,071
44$1,358,771$1,088,006
45$1,550,805$1,211,487
46$1,759,190$1,340,758
47$1,985,157$1,476,075
48$2,230,026$1,617,706
49$2,495,213$1,765,930
50$2,782,236$1,921,038
51$2,976,992$2,005,376
52$3,185,382$2,093,417
53$3,408,359$2,185,323
54$3,646,944$2,281,264
55$3,902,230$2,381,417
56$4,175,386$2,485,968
57$4,467,663$2,595,108
58$4,780,399$2,709,039
59$5,115,027$2,827,973
60$5,473,079$2,952,127
61$5,856,195$3,081,733
62$6,266,128$3,217,029
63$6,704,757$3,358,264
64$7,174,090$3,505,700
65$7,676,277$3,659,609

Scenario benchmark

Using the preset inputs, here is the calculated FIRE projection for Fat FIRE for a Tech Engineer.

FIRE number

$3,428,571

Financially independent at

64 yrs

Portfolio at target age

$2,782,236

Sustainable annual income

$67,236

Investment growth

$6,137,155

Coverage of the FIRE number

56%

Frequently asked questions

How the maths works

The projection compounds monthly and separates nominal currency from real purchasing power, because a portfolio that doubles while prices double has not made you richer.

  1. 1Convert the annual return r into a monthly rate: rm = (1 + r)^(1/12) − 1.
  2. 2For every month: balance = balance × (1 + rm) + contribution.
  3. 3Increase the contribution once per year by the salary-growth rate.
  4. 4Deflate the balance to today's money: real = nominal ÷ (1 + i)^years, where i is inflation.
  5. 5FIRE number = annual spending ÷ safe withdrawal rate (4% → 25× spending).
  6. 6Inflate the target forward each year and report the first year the nominal balance clears it.

Returns are modelled as a smooth average. Real markets are volatile and sequence-of-returns risk matters in the first years of withdrawal — treat the output as a planning baseline, not a promise.

Everything you need to know

Why compounding beats contribution size over time

In the first years, almost all portfolio growth comes from the money you deposit. Somewhere between year ten and year fifteen — depending on the return you assume — the annual gain produced by the portfolio itself overtakes the annual contribution. From that point on, time in the market matters more than the size of each deposit.

This is why the chart shows contributions and total balance separately: the gap between the two lines is the part of your wealth that compounding built for you.

Reading the 4% rule correctly

The 4% safe withdrawal rate comes from the Trinity study and its successors, which tested historical 30-year retirements against a portfolio of stocks and bonds. It implies a FIRE number of roughly 25 times annual spending.

It is a heuristic, not a law. Longer retirements, lower expected returns, high fees or an early bear market all argue for a lower rate — 3.25% to 3.5% is a common conservative choice, which raises the target to roughly 29–31 times spending.

  • 4.0% → 25× annual spending
  • 3.5% → about 29× annual spending
  • 3.0% → about 33× annual spending
  • 5.0% → 20× annual spending, but with materially higher depletion risk

Inflation is the quiet variable

At 2.5% inflation, prices roughly double in 28 years. A portfolio target set in today's money must therefore be inflated to the year you actually retire, otherwise you will hit a nominal number that no longer buys the life you planned.

The calculator does both: the nominal line shows the balance you will literally see in your account, and the real line shows what it is worth in the prices you know today.

FIRE scenarios

Pre-filled starting points for common Financial Independence goals.

Fat FIRE for a Tech Engineer

A senior tech professional who wants a comfortable, premium retirement rather than a lean one.

You are here
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A location-independent worker who keeps expenses low so the target portfolio stays small.

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Coast FIRE in Your 20s

A young saver who front-loads contributions and then coasts on market growth.

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