Lean, Fat, Coast, Barista — the types of FIRE explained

FIRE — financial independence, retire early — is not one plan with one number. It is an equation with two open variables (spending and a withdrawal rate) and a timeline, and "Lean," "Fat," "Coast," and "Barista" are simply names for which of those variables a plan leans on to get somewhere different. None of them changes the underlying maths; each just moves a different lever.

That matters because the labels get treated as four separate lifestyles to choose between, when they are better understood as four answers to the same question: given how much I actually spend, how much I want to spend, how long I am willing to wait, and how much paid work I am willing to keep doing, what does my number look like? Work through the levers in order and the type that fits usually becomes obvious rather than chosen.

Four levers, one equation

Every FIRE number starts from the same relationship: portfolio target equals annual spending divided by withdrawal rate. Push spending down and the target falls. Push spending up and it rises. Change nothing about spending but stretch how long the money has to grow, and the balance you need today falls even though the eventual target does not. Keep working part-time instead of stopping entirely, and the portfolio only has to cover the gap paid work does not. Lean, Fat, Coast, and Barista are what happen when you pull each of those levers on its own — the four-percent rule is the withdrawal-rate half of the equation each of them still depends on, and it is worth understanding before comparing the four.

Lean FIRE: spending down

Lean FIRE moves the spending lever down. Instead of funding your current lifestyle, you price a deliberately minimal one — smaller housing, no dependants' private schooling, modest travel — and build the FIRE number against that figure instead. Someone spending $30,000 a year needs a portfolio of $750,000 at a 4% withdrawal rate, against $1.2 million for a household spending $48,000. The smaller number is reached sooner on the same savings rate, which is the entire appeal.

The tradeoff is margin. A lean budget has little room for an expense shock — a major repair, a health cost, a bad year for a landlord to raise rent sharply — because the plan was built with the fewest optional categories in the first place. Lean FIRE suits people whose current spending is already close to the target, not people planning to cut sharply the day they stop working; a lifestyle rehearsed for a few years before the number is hit is far more reliable than one assumed on paper. The lean FIRE calculator prices a bare-bones number from five essential categories rather than a single guessed figure.

Fat FIRE: the target up

Fat FIRE moves the same lever the other way: a bigger annual spending figure, funding a fuller lifestyle rather than a pared-down one, with the target sized accordingly. At $96,000 a year, the 4% number is $2.4 million — double the spending, double the portfolio, same arithmetic. Many Fat FIRE plans also shift the withdrawal rate down to 3.5% rather than 4%, on the reasoning that a larger absolute dollar amount riding on the portfolio has more to lose from an unlucky sequence of returns early in retirement; at 3.5%, that same $96,000 becomes a target of roughly $2.74 million.

Fat FIRE suits people whose fixed costs are already high and not easily cut — an expensive housing market, dependants' education, ongoing support for family — or who simply want retirement to fund the same lifestyle current income does, undiminished. It usually takes a higher income, a longer working stretch, or both, to reach; it is the version of the plan built for people unwilling to trade lifestyle for an earlier date. The fat FIRE calculator grosses the number up for the tax a large withdrawal usually triggers, which a simple spending-times-25 estimate leaves out.

Coast FIRE: stretching the timeline

Coast FIRE leaves spending and the eventual target alone and instead moves the timeline. The idea: if you have already saved enough that growth alone — with no further contributions — will reach your full number by a normal retirement age, you can stop adding to the portfolio today and simply let it compound. You still work, and your income still needs to cover today's spending, but none of it has to go toward retirement any more.

Take someone age 30 who spends $48,000 a year, whose full FIRE number at 4% is $1.2 million, and who has already built $217,500. Invested at a 5% real return with no further contributions, compounding alone carries that balance to roughly $1.2 million by 65 — the same number the full calculation targets, reached without saving another dollar for it.

A $217,500 balance coasting to $1.2 million

	Portfolio value
Age 30	217500
40	354300
50	577100
Age 65	1200000

Assumes a 5% real annual return and no further contributions after age 30.

Coast FIRE suits people who front-loaded savings early — a strong first decade of income, an early inheritance, a high starting savings rate — and now want flexibility rather than a bigger cushion: a lower-paying but more interesting role, reduced hours, a career change with a pay cut. What it does not offer is an early exit; you keep working until the traditional finish line, just without the added pressure of also having to save while you do. The coast FIRE calculator works this figure out from your own age, target, and return assumption, and the coast FIRE mathematics walks through why the "stop contributing" line lands where it does.

Barista FIRE: bridging the gap with income

Barista FIRE moves the fourth lever: how much of ongoing spending paid work still needs to cover. Rather than funding all of it from withdrawals, a smaller portfolio funds part of it, and continuing part-time income covers the rest — the name borrows from the idea of a lower-stress job replacing a full-time career rather than ending work outright.

Run the same $48,000-a-year household through it. Part-time income of $16,000 a year leaves a $32,000 gap; at 4%, that gap needs $800,000 rather than the full $1.2 million — a third smaller, and reachable considerably sooner on the same savings rate. In Canada the appeal is less about employer health coverage than it is in places without universal care, and more about structure, income continuity, and simply not stopping paid work cold — for some, a part-time role that still tops up a workplace benefits plan or a pension is worth planning around directly.

Run your numbersFIRE number→

Barista FIRE suits people who want to leave a demanding career sooner without giving up income and structure entirely, and who are comfortable with a plan that depends partly on continuing to be employable in some form indefinitely — which is its real tradeoff against the other three: a Barista plan is only as durable as the part-time income it counts on. The barista FIRE calculator solves the gap for any target income and spending pair rather than the one example above.

Comparing the four

All four numbers below assume the same $48,000-a-year household and a 4% withdrawal rate except where noted, so the only thing changing between rows is the lever each variant pulls:

Moving between them

Few people commit to one label permanently, and the useful way to think about the four is as positions you pass through rather than a single choice made once. A few paths show up repeatedly:

• A high-income early career reaches a Coast number well before it reaches a full one, and the plan shifts from "save aggressively" to "let it ride" without anyone renaming it at the time.
• A Fat target proves further away than the working years someone actually wants to put in, and the plan downshifts to Barista or Lean — trading some of the cushion for reaching independence sooner.
• A Coast plan gets knocked off track by a market downturn or a job loss, and contributions resume, or part-time income steps in to close the gap Coast alone no longer covers on its own.
• Spending itself changes — a home paid off, dependants grown, a move to a cheaper area — and a household drifts from Standard toward Lean, or the reverse, without any deliberate decision to switch types.

None of this requires picking a lane in advance. Work out your FIRE number at your actual spending first, check it against a FIRE calculator with your own savings rate and timeline, and the variant that fits will usually be visible in the gap between where you are and where the standard number sits — closer than expected points toward Coast, a long way off points toward Lean or Barista, and a lifestyle you are unwilling to shrink points toward Fat.