Coast FIRE vs Full, Lean and Barista FIRE
By Retire Growth · Updated 2026-10-27 · No independent professional financial review is claimed.
Four planning questions that use different relationships between work income, spending and investments.
Coast, Full, Lean and Barista FIRE describe different funding questions. They do not identify investment products or guarantee retirement outcomes. Comparing the cash flows behind the labels is more useful than choosing a label first.
Coast: investments for a later date
Coast FIRE asks how much needs to be invested now so that growth alone could reach a later retirement target. Current living costs are funded separately. The model leaves the investments untouched during this period.
The key input beyond spending and a withdrawal assumption is time. Discounting the future target by the chosen real growth factor gives today's Coast threshold. The Coast FIRE calculator shows this threshold and a possible crossing while you keep saving.
Full FIRE: the whole spending budget
Full FIRE asks about a portfolio that could support the entered spending budget when financial independence begins. The simplified sizing formula is annual spending divided by an initial withdrawal fraction. At an illustrative 4%, a $48,000 annual budget implies a $1,200,000 target.
That ratio is arithmetic, not proof that withdrawals will last. A long retirement, adverse market returns, taxes and rising costs can all change the practical question.
Lean: a smaller personal budget
Lean FIRE uses a smaller spending plan. There is no universal spending cutoff in our model. A person must decide which housing, health, tax and irregular costs belong in the budget before the target calculation is meaningful.
For an illustrative $30,000 annual budget at 4%, the target is $750,000. Reducing spending changes the target directly, but the formula does not test how resilient that budget is to surprises.
Barista: part-time income covers a gap
Barista FIRE subtracts ongoing net work income from spending before sizing the portfolio. For a $48,000 spending budget and $18,000 of annual part-time income, the investment gap is $30,000. At an illustrative 4%, that gap implies a $750,000 portfolio target.
This assumes the income continues when needed and is measured on the same after-tax and inflation basis as spending. If work stops, the portfolio may need to cover the full budget. A temporary income stream requires a separate time-based model.
Keep the units consistent
A future-dollar salary should not be subtracted directly from a today-dollar spending budget. Gross pay should not silently become take-home income. A Coast balance today should not be mistaken for a portfolio ready to fund withdrawals now.
Our current release focuses on Coast FIRE. Dedicated tools for other approaches are later work; these examples explain the differences rather than present those tools as live. Read the calculation method, the Coast age guide and the withdrawal-rate limitations for the assumptions behind the comparison.
Updated October 27, 2026. Educational content; no independent professional financial review is claimed.