FIRE Calculator - Financial Independence Planner (2026)

How Much Do I Need to Retire? What Is My FIRE Number?

Your FIRE number is annual portfolio-funded spending divided by a sustainable withdrawal rate. At the classic 4% from Bengen 1994, you need 25× spending: $40,000 needs $1,000,000, $60,000 needs $1,500,000 and $80,000 needs $2,000,000. At 3.5% you need 28.57×: $60,000 needs $1,714,286, about $214,000 more than at 4% (Source: Bengen 1994; Cooley, Hubbard & Walz Trinity Study — 2024 update ~82% success at 4% over 30yr). Lean FIRE ($30k-$40k) targets about $750k-$1,333k, Fat FIRE ($100k) about $2.5M at 4%. Use the Retirement Savings Calculator to see the same $30,000 yearly grown without a part-time offset.

How Long Until I Reach Financial Independence at 3.88% Real?

Nominal return minus inflation is not the real return you should use — the formula is (1+nominal)/(1+inflation)−1. At 7% nominal and 3% inflation, real is 3.88%, so $100,000 for 20 years becomes $214,100 real and $30,000 yearly becomes $854,400, totaling about $1,068,500 real. At 6% nominal and 2.5% inflation, real is 3.41% and the total is about $987,000, $81,500 less. A 0.5% higher real return for 20 years adds about $110,000 on $30k yearly. At 6% nominal and 2.5% inflation, real is 3.41% and the same $30,000 for 20 years totals about $987,000 real versus $1,068,500 at 3.88% real, an $81,500 gap that shows why 0.5% real matters over 20 years.

Past performance does not guarantee future results; this assumes a constant 3.88% real and no taxes or fees. Raising savings from $30,000 to $36,000 adds six $6,000 yearly increments that each compound, adding about $170,000 over 20 years at 3.88% real. Model the paycheck side with the Payroll Calculator if you plan Barista part-time work.

Is a 4% Withdrawal Rate Safe or Should I Use 3.5%?

The 4% rule was based on U.S. historical data for a 50% stock / 50% bond portfolio over 30 years with annual inflation adjustments. The 2024 Trinity update showed about 82% inflation-adjusted success at 4% and about 90% at 3.5% over 30 years (Source: Trinity Study update 2024). The difference on $60,000 spending is $214,286 in required capital ($1,714,286 at 3.5% vs $1,500,000 at 4%).

Lower than 4% raises the required $1.5M by $214k and the years to FI at $30k yearly from about 25 to 28 years on $100k start. Higher than 4% cuts capital but raises failure risk, especially for early retirees with 40+ year horizons. Use the Compound Interest Calculator to stress the same $30k at 3.88% real versus 2.88% real.

Barista FIRE vs Fat FIRE: How Does Part-Time Income Change the Target?

Barista FIRE subtracts reliable part-time income before dividing by the withdrawal rate. At $60,000 spending, $0 part-time at 4% needs $1,500,000, $20,000 part-time needs $1,000,000 and $30,000 part-time needs $750,000 — the same as Lean FIRE on $30,000 spending with no part-time. The $20,000 part-time reduces the required portfolio by $500,000 (33.3%) and cuts the time to FI at 3.88% real from about 23 years to 17 years on $100k start + $30k yearly.

Fat FIRE is the opposite: $100,000 spending needs $2,500,000 at 4% and $3,333,333 at 3% without part-time, requiring about 28 years at $30k yearly versus 23 years for $60k. Health insurance and taxes often drive Barista math: a $12,000 health cost that part-time covers is equivalent to $300,000 of portfolio at 4% ($12,000/0.04). Plan the income stream that replaces that portfolio slice, not just the headline FI number.