There's a point in your wealth-building journey where compound growth takes over. Where your existing investments, left untouched, will grow to your FIRE number by retirement age — even if you never invest another dollar. That point is called Coast FIRE.

For Australian professionals who feel the pressure of aggressive saving, Coast FIRE offers a liberating alternative. Instead of grinding toward a multi-million-dollar portfolio for decades, you front-load your savings early, then let compound growth do the heavy lifting while you downshift to a lower-stress career, reduce your hours, or simply stop worrying about your savings rate.

What is Coast FIRE?

Coast FIRE is the amount of invested assets you need right now such that, with no additional contributions, your portfolio will grow to your full FIRE number by your target retirement age.

Once you reach Coast FIRE, you only need to earn enough to cover your current living expenses. You don't need to save or invest anything more — your existing investments are "coasting" to your retirement target on their own.

The concept sits between regular FIRE (full financial independence) and simply having a good savings habit. You're not yet free from needing to work, but you're free from needing to save.

The math behind Coast FIRE

Coast FIRE relies on one of the most powerful forces in finance: compound growth. The formula is straightforward:

Coast FIRE number = FIRE number / (1 + real annual return) ^ years until retirement

Where:

• FIRE number is your target portfolio at retirement (typically annual expenses × 25)
• Real annual return is your expected investment return after inflation
• Years until retirement is how long your money has to grow

The "real return" part is important. By using inflation-adjusted returns, you get a Coast FIRE number in today's dollars — which is much easier to think about.

A diversified portfolio of ETFs has historically delivered roughly 6% real returns (after inflation) over long periods. Superannuation balanced options have delivered around 4-5% real.

Coast FIRE numbers by age

Let's say your FIRE number is $2,000,000 (enough to withdraw $80,000 per year at a 4% safe withdrawal rate). Assuming a 6% real return, here's your Coast FIRE number at different ages, targeting age 60:

At 30, you'd need roughly $349,000 invested to coast to $2 million by 60. At 25, just $260,000. The earlier you start, the less you need — because your money has more time to compound.

This is why Coast FIRE is particularly appealing to people in their late twenties and early thirties who've been saving aggressively. A few years of disciplined saving early in your career can set you up so that compound growth handles the rest.

Coast FIRE in the Australian context

Australia's retirement system actually has a built-in Coast FIRE mechanism: superannuation.

Your employer contributes 12% of your salary into super every year. That money is invested and compounds over decades until you can access it at preservation age (60 for most people). Even if you never made a single voluntary contribution, your super balance would grow substantially through employer contributions and investment returns alone.

But for FIRE planning, there's a crucial distinction between super and accessible investments.

Super is already "coasting" for you

Consider a 30-year-old with $80,000 in super. If they stopped contributing entirely (hypothetically), at a 7% nominal return that $80,000 would grow to roughly $609,000 by age 60. Add in 30 more years of employer SG contributions on a $150,000 salary (growing with wage inflation), and the super balance could reach well over $1.5 million.

In many cases, super alone gets you a significant portion of the way to your FIRE number — without any voluntary effort.

The bridge period still matters

The catch is that super is locked until 60. If you reach Coast FIRE at 35, you still need to cover 25 years of living expenses before you can access super. You don't need to save for retirement anymore, but you do need to keep earning.

This is where Coast FIRE differs from full FIRE. You're not financially independent — you still need income. But you only need enough income to cover your current expenses, with no need to save for the future.

For some people, that means switching from a high-pressure, high-paying career to something less demanding. For others, it means going part-time, freelancing, or pursuing work they find meaningful regardless of pay.

Coast FIRE vs other FIRE variants

Understanding where Coast FIRE sits among the different approaches helps you decide if it's right for you.

Regular FIRE — You have enough invested to cover all expenses indefinitely. You never need to work again. This requires the full FIRE number (e.g., $2,000,000).

Lean FIRE — Same as regular FIRE, but with minimal expenses. Lower target, tighter lifestyle.

Fat FIRE — Same as regular FIRE, but with generous expenses. Higher target, comfortable lifestyle.

Barista FIRE — You have enough that part-time work covers the gap between your investment income and your expenses. Similar to Coast FIRE, but typically implies a smaller portfolio and a specific plan for part-time income.

Coast FIRE — Your investments will grow to your FIRE number without further contributions. You still need to earn your living expenses, but you don't need to save. The key difference from Barista FIRE is that Coast FIRE is defined by your portfolio's growth trajectory, while Barista FIRE is defined by the income gap.

Who Coast FIRE suits

Coast FIRE is particularly appealing if you:

• Saved aggressively in your twenties and early thirties and want to ease off the intensity
• Want to change careers to something less lucrative but more fulfilling
• Want to work part-time or take extended breaks without worrying about retirement
• Feel burnt out from the relentless saving required for traditional FIRE
• Have a partner whose income can cover household expenses while your portfolio compounds
• Value time and flexibility now rather than waiting for full financial independence in your forties or fifties

It's less suitable if you want to stop working entirely in the near future, or if you're already close to your target retirement age (less time for compounding means a higher Coast FIRE number, making it less meaningfully different from regular FIRE).

How to calculate your personal Coast FIRE number

To work out your Coast FIRE number, you need three inputs:

1. Your FIRE number — Annual retirement expenses × 25 (or ÷ 0.04 if using the 4% rule)
2. Your target retirement age — When you want to access your full portfolio
3. Your expected real return — Typically 5-7% for a growth-oriented portfolio after inflation

Then apply the formula: FIRE number ÷ (1 + real return)^years.

But for Australian FIRE planning, you actually need to calculate two Coast FIRE numbers:

• Super Coast FIRE — Will your super balance grow to cover your post-60 retirement needs?
• Accessible investments Coast FIRE — Will your non-super investments grow to cover the bridge period between early retirement and super access?

This dual calculation is what makes Australian Coast FIRE planning more nuanced than the American version. You're essentially managing two separate portfolios with different access dates.

How Wealth Dashboard calculates Coast FIRE

Wealth Dashboard's projection engine calculates your Coast FIRE number automatically, factoring in the Australian-specific complexity that spreadsheets struggle with.

When you create a projection, the system:

• Calculates your Coast FIRE number based on your actual expenses, current portfolio, and target retirement age
• Separates super from accessible investments so you can see whether each bucket is on track to coast independently
• Models employer SG contributions that continue to build your super while you're still working
• Accounts for tax on investment earnings both inside and outside super

You can experiment with different scenarios using the simulation engine to see how changes to your savings rate or investment strategy affect when you reach Coast FIRE. Try the free FIRE calculator to get your baseline numbers, or create a Wealth Dashboard account for the full projection with super separation and year-by-year breakdowns.

A practical Coast FIRE example

Sarah is 32, earning $180,000. She has $120,000 in super and $95,000 in ETFs. Her annual expenses are $70,000, giving her a FIRE number of $1,750,000.

Coast FIRE calculation (targeting age 60, 6% real return):

• Years to 60: 28
• Coast FIRE number: $1,750,000 / (1.06)^28 = $342,000

Sarah's total invested assets are $215,000 ($120,000 super + $95,000 ETFs). She needs $342,000 to reach Coast FIRE. That's a gap of $127,000.

If she saves $40,000 per year (after tax and expenses), she'll close that gap in roughly three years — reaching Coast FIRE at 35.

At that point, she could switch to a lower-paying job she enjoys more, go part-time, or take a gap year — whatever she wants. Her portfolio, left alone, is projected to grow to $1.75 million by 60 without another dollar invested.

She still needs to cover her $70,000 annual expenses, but she doesn't need to save. That's a fundamentally different financial position than needing to earn $110,000+ to cover expenses and savings.

The psychological benefit

Beyond the numbers, Coast FIRE offers something powerful: the removal of financial anxiety about the future. Once you know your retirement is mathematically handled, the pressure to maximise income and savings rate dissolves.

For high-income professionals who've spent years optimising every dollar, reaching Coast FIRE is permission to stop optimising. To choose work based on meaning rather than money. To say no to the promotion that comes with 60-hour weeks. To take the sabbatical.

That shift — from "I must save more" to "I'm already on track" — can be worth more than any dollar amount.

Start calculating your Coast FIRE number

Understanding where you stand relative to Coast FIRE can fundamentally change how you think about your career and savings strategy. You might be closer than you think.

Use our free FIRE calculator to see your current trajectory, or create a Wealth Dashboard account to get detailed Coast FIRE projections that separate super from accessible investments and show exactly when compound growth takes over.

For more on the different paths to financial independence, see our complete guide to FIRE in Australia.