Coast FIRE, Barista FIRE, Lean FIRE: pick your target

The FIRE movement has generated more terminology than almost any other personal finance community. Most of the terms are used imprecisely, which creates the impression that choosing between them is a matter of taste rather than mathematics. It isn't. Each variant of FIRE corresponds to a specific financial situation with specific trade-offs, and picking the wrong target is one of the most common ways people end up working harder than they need to, or retiring earlier than they can afford.

This post defines the four main variants honestly, explains what each requires, and helps you work out which one your current savings trajectory actually points toward.

The canonical FIRE definition

Before the variants, the baseline. Standard FIRE — sometimes called "Full FIRE" or just "FIRE" — means accumulating a portfolio large enough that investment returns fully cover your living expenses indefinitely. The arithmetic is the inverse of a withdrawal rate: at 4% withdrawal, you need 25 times your annual spending. At 3.5%, you need roughly 28.5 times. At 3%, you need 33.3 times.

A household spending £40,000 a year targeting 3.5% SWR needs £1.14M. A household spending £80,000 needs £2.28M. These numbers are what the anchor post in this series works through in detail for three jurisdictions.

Full FIRE is the most financially demanding variant. It assumes you will never earn money again after your retirement date. It builds a portfolio large enough to survive bad sequences, inflation, and a potentially 40-year horizon with no new contributions. It is also, consequently, the variant most people cannot actually reach in a reasonable timeframe without extreme savings rates.

Most FIRE variants exist because most people, looked at honestly, are not going to reach Full FIRE. The variants are what you do instead.

Coast FIRE

Coast FIRE is the mathematical observation that if you save aggressively early enough, compound growth alone can carry you to a traditional retirement without further contributions. The "coast" is the period after your required saving stops.

The mechanics: you accumulate a portfolio by some age X, stop contributing, and let it compound at the real return rate until your chosen retirement age Y, at which point it reaches your full FIRE number. Your working life between X and Y only needs to cover current expenses, not fund retirement.

Worked example. Assume 5% real investment returns, target retirement age of 65, desired retirement spending of £40,000 per year requiring £1M at 4% SWR. Working backwards: you'd need £481k by 50, £295k by 40, or £232k by 35. The further in the future your chosen retirement age, the smaller the portfolio you need right now.

Accumulating £232,000 by age 35 is a much less demanding task than accumulating £1M by age 45. From age 35 onwards, you only need to earn enough to cover current expenses. You can switch careers, work part-time, take sabbaticals, or take a lower-paying job you enjoy more.

Coast FIRE is not early retirement. It is early freedom from retirement-saving pressure. The terminology is misleading because people hear "FIRE" and assume the retire-early component. Coast FIRE explicitly defers retirement to a traditional age in exchange for lower lifetime required earnings.

The trade-off: Coast FIRE assumes your real return assumption is correct for the next 30 to 40 years. A 5% real return assumption is generous by historical standards for non-US markets. At 4% real (closer to the global historical average per Anarkulova 2025), the Coast FIRE numbers become much larger. At 3% real, the approach barely works. The further out your retirement age, the more sensitive the plan is to return assumptions, and the more a bad sequence in the coasting period can wreck it.

Barista FIRE

Barista FIRE is Full FIRE minus some amount, with the gap covered by part-time or low-intensity work. The name comes from the original idea that your part-time work might be as a barista at Starbucks, where US workers could historically access employer health insurance without full-time hours — a meaningful consideration in the pre-ACA US healthcare system. The term has stuck even as the specific reference has become dated.

The mechanics: you accumulate a portfolio large enough to cover some fraction of your expenses, and work for the remainder. If you need £40,000 annually and your portfolio covers £25,000 (meaning £714k at 3.5% SWR), your part-time work needs to generate the remaining £15,000 post-tax. That's perhaps 15-20 hours a week at a modest hourly rate, sustainable almost indefinitely, and the portfolio stays largely intact to serve as a full retirement fund when you stop working entirely.

Barista FIRE is the variant most people actually achieve, even if they don't call it that. Millions of people in their fifties and sixties work reduced hours supplementing pension income — that's Barista FIRE under a different name. The FIRE framing makes it a target rather than a fallback, which is the genuinely useful contribution of the terminology.

The trade-offs are real but bounded. You are still working, just less. Your work has to exist — some careers don't have part-time equivalents, which limits which jobs can support this lifestyle. Your earnings have to stay relatively stable, which depends on health, industry, and luck. Healthcare arrangements matter enormously in the US and much less in the UK, France, and most of the EU.

The sequence risk story from the previous post in this series applies here too, with a twist: Barista FIRE is more resilient to sequence risk than Full FIRE, because the earned income specifically reduces withdrawals during any bad period. A Barista FIRE retiree who needs £15,000 from work and £25,000 from portfolio is drawing £25,000 even during a bad first decade, not £40,000. That 40% reduction in portfolio withdrawals during the sequence-risk-critical period is a significant structural advantage.

Lean FIRE

Lean FIRE is Full FIRE at a low spending level. The variant assumes the retiree is willing and able to live on materially less than conventional retirement budgets, which makes the required portfolio proportionally smaller.

The convention in the US FIRE community has been to define Lean FIRE as requiring less than $40,000 per year in retirement spending, though the threshold is arbitrary. In the UK, a reasonable working definition is under £30,000 per year; in the EU, under €30,000.

The appeal is obvious: at 3.5% SWR, a £25,000 spending target requires £714k rather than the £1.14M needed for a £40,000 target. The portfolio required is 37% smaller, which can easily represent ten fewer years of accumulation.

The trade-offs are harder to quantify honestly.

Lean FIRE works for people who genuinely have low fixed costs and whose values genuinely align with a lower-spending lifestyle. It does not work for people who are rationalising a retirement they can't actually afford. The distinction matters because lifestyle inflation is invisible until tested. Someone who has been earning £80,000 and spending £50,000 will find it much harder to stabilise at £25,000 than someone who has been earning £40,000 and spending £25,000 all along. The Lean FIRE maths is the same for both; the psychological difficulty is not.

Lean FIRE also depends critically on health and housing. If you plan to Lean FIRE at £25,000 per year in a paid-off house in a low-cost area, the maths works. If you plan to Lean FIRE at £25,000 while renting in London, you are running a plan that assumes rents will not outpace investment returns over thirty years, which is historically a poor assumption. The housing situation is the single largest variable in whether Lean FIRE is actually viable.

Healthcare, again, is a US-specific concern. In the UK, France, Germany, and most developed systems outside the US, a Lean FIRE retiree has the same healthcare access as anyone else. In the US, the viability of Lean FIRE depends on ACA subsidy structure, which depends on policy choices made by Congress, which is a risk factor the FIRE community tends to downplay.

Fat FIRE

For completeness: Fat FIRE is Full FIRE at a high spending level — typically defined as more than $100,000 per year in the US or more than £80,000 in the UK. The maths is mechanically identical to Full FIRE, just with a bigger number: at 3.5% SWR, £100,000 per year requires £2.86M. It is achievable by people with high-earning careers who can save aggressively while spending generously, and not achievable by most others in a reasonable timeframe. For most savers, the realistic range runs from Lean through standard Full FIRE; Fat is mentioned mainly as the upper bound of the taxonomy.

How to pick

The honest way to approach this is not to choose a variant first and build a plan around it. It's to calculate your current accumulation trajectory and see which variant it actually points to.

Start with three numbers: your current portfolio value, your current annual savings, and a real return assumption (3-4% is honest for a globally diversified investor; 5-6% is optimistic). Project forward to your desired retirement age. Calculate what annual spending that portfolio supports at 3-3.5% SWR.

One of four things will be true.

If the projected spending matches or exceeds your current lifestyle, you're on track for Full FIRE. Keep doing what you're doing, possibly with some slack to reduce savings or accelerate retirement.

If the projected spending falls short but you could cover the gap with a smaller ongoing income, you're on track for Barista FIRE. Plan around what kind of part-time work you could sustain and whether your skills translate to it.

If the projected spending is well below your current lifestyle but you genuinely would be content with less, you're on track for Lean FIRE. The critical check is whether you've actually lived on that lower number for a meaningful period. If you haven't, the plan is untested.

If the projected portfolio is smaller than your Full FIRE number but large enough to coast on, you're on track for Coast FIRE at traditional retirement age. Plan your career trade-offs accordingly.

Most people's honest answer is some combination. A common trajectory is Coast FIRE by 40, optional Barista FIRE by 50, Full FIRE by 60. That progression is not a failure mode. It's a rational staircase of options, each of which reduces the pressure on the next.

The mistake is treating these variants as identity labels rather than financial situations. No-one "is" a Lean FIRE person or a Barista FIRE person. They have a portfolio, a spending pattern, and a set of options. The variant is what emerges from those inputs, not a lifestyle badge to pursue.

Where Endute fits

Endute's FIRE simulator doesn't force you to pick a variant upfront. You enter your current situation and target retirement age, and the output shows what spending level is achievable, under what assumptions, and how sensitive the answer is to return variation. The variant emerges from the numbers, which is the right order of operations for serious retirement planning.

A note on terminology

These terms originated in online communities (Mr. Money Mustache, Bogleheads, r/financialindependence) and are not standardised — different sources use slightly different thresholds and trade-offs. The definitions above reflect common 2026 usage. More specialised terms (Flamingo FIRE, Coast-Barista hybrids) exist but add little; the four variants here, plus Fat as a contrast point, capture essentially all the real strategic choices.

This is the sixth post in a cluster on early retirement planning. The preceding posts cover the headline FIRE calculation, the tax-advantaged wrappers that build the pot, the bridge problem of accessing it before pension age, sequence-of-returns risk, and why the 4% rule performs poorly outside the US. Future posts in the series examine stress-testing your FIRE number, tax-efficient withdrawal order in early retirement, and what happens to FIRE plans if inflation stays high for a decade.