Updated · Built and checked by the PlinzoTools team, formulas tested against published sources
Calculate the nest egg needed to support your desired spending indefinitely (Financial Independence).
$1000000.00
FIRE (Financial Independence, Retire Early) planning centers on one key number: how large a nest egg supports your desired spending indefinitely. This is the inverse of the Retirement Withdrawal Calculator's question -- instead of starting with a nest egg and finding a sustainable withdrawal, this starts with your desired spending and solves for the required nest egg (the "FIRE number").
Enter your desired annual expenses in retirement and your chosen safe withdrawal rate (4% is the classic FIRE-community starting point, though some prefer 3-3.5% for extra safety margin given a potentially very long retirement).
FIRE Number = Annual Expenses ÷ Withdrawal Rate %
This is mathematically the same as multiplying annual expenses by 25 (the inverse of a 4% withdrawal rate) -- the widely cited "25x expenses" FIRE rule of thumb.
A lower (more conservative) withdrawal rate requires a larger nest egg but provides more safety margin, especially relevant for early retirees planning for a retirement that could last 40-50+ years, much longer than the traditional ~30-year retirement horizon most withdrawal-rate research is based on.
The FIRE number is only as accurate as the spending figure you enter, and this is where most people go wrong. Use your expected spending in retirement, not your current income. Build it from categories: housing, food, transportation, healthcare, insurance, taxes, travel, and a cushion for irregular costs such as roof repairs or car replacement. Review a year of actual bank and card statements to avoid guessing. If you will pay off your mortgage before retiring, leave that payment out, but keep property taxes and upkeep.
Using hypothetical figures, compare $50,000 in yearly expenses at three rates. At 4% the FIRE number is $1,250,000. At 3.5% it is about $1,428,571. At 3% it is about $1,666,667. Now compare a $10,000 cut in expenses at 4%: the target falls by $250,000. Trimming spending shrinks the target by 25 times the savings, which is often easier than saving more or waiting for higher returns. This is why FIRE planning focuses so heavily on expenses.
Once you have a target, compare it with your current investments to see how far along you are. Then use a growth projection tool such as the Retirement Calculator to estimate how many years it would take with your current savings rate. If the timeline is longer than you like, adjust spending, savings, or the planned retirement age and rerun the numbers.
This page is educational. A fee-only planner can help stress test a plan for early retirement.
The 4% rule's research was based on roughly a 30-year retirement horizon -- someone retiring in their 30s or 40s needs their money to last considerably longer, so many FIRE planners use 3-3.5% instead for extra safety margin.
Yes -- dividing by a 4% withdrawal rate is mathematically identical to multiplying by 25, so both describe the same FIRE number calculation.
Yes. Include realistic premiums and out-of-pocket costs in your annual expenses, especially if you retire before Medicare eligibility.
Yes. If you expect income in retirement, subtract it from annual expenses before entering, so the portfolio only has to cover the gap. Be realistic about how reliable that income will be.
Spending often shifts across life stages. Run the tool with a higher and a lower figure to bracket the range, and revisit it regularly.
No. It marks the point at which your portfolio could cover your stated spending at the chosen rate. Many people keep working part time for flexibility.
Reference: Social Security Administration