Coast FIRE Calculator Financial Independence

Understanding Coast FIRE

Coast FIRE is the moment your invested savings become large enough that you no longer need to add another dollar to retire on time. From that point on, ordinary compound growth carries the portfolio the rest of the way. You still have to work to cover today's living expenses, but you are free to stop retirement saving and "coast" into retirement. It is the lowest, most achievable milestone on the FIRE (Financial Independence, Retire Early) ladder.

The appeal is psychological as much as financial. Hitting your Coast FIRE number means the hardest part — building the base — is done. A 32-year-old who has coasted can switch to a lower-paying but more meaningful job, take a career break, or simply stop stressing about their 401(k), and still expect a fully funded retirement at 60. Use the Compound Interest Calculator and Savings Calculator to plan your journey.

Coast FIRE Formula

The calculator uses a two-step calculation:

Target Corpus: The nest egg needed at retirement: $$\text{Target} = \frac{\text{Annual Spending}}{\text{Withdrawal Rate}}$$
Coast Number: The amount needed today to reach that target: $$\text{Coast Number} = \frac{\text{Target}}{(1 + r)^n}$$

Where $r$ is the expected real return (after inflation) and $n$ is the number of years until retirement.

How to Use the Calculator

Enter your current age and desired retirement age.
Enter your expected annual spending in retirement (in today's dollars).
Set your safe withdrawal rate (4% is the common default) and expected real return (7% is a common long-run stock assumption).
Enter your current invested savings and monthly contribution amount.
The calculator shows your Coast FIRE number, whether you've reached it, and how many years until you can coast.

Frequently Asked Questions

What is Coast FIRE?

Coast FIRE is the point where your existing investments are large enough that they will grow to fully fund your retirement without any additional contributions. You still need to work for living expenses, but you can stop saving for retirement.

Coast FIRE vs Barista FIRE — what's the difference?

Coast FIRE means you stop retirement contributions entirely. Barista FIRE means you downsize to a part-time job (often with benefits, like at Starbucks) and cover reduced living expenses while your investments continue growing. Barista FIRE is a middle ground between Coast FIRE and full FIRE.

Is Coast FIRE realistic?

For many people, yes — especially younger workers with a long time horizon. The power of compounding over decades makes the Coast FIRE number much lower than the full FIRE number. However, it depends on realistic return assumptions and consistent spending habits.

How do you calculate your Coast FIRE number?

First, determine your target nest egg by dividing your annual retirement spending by your safe withdrawal rate (e.g., $40,000 / 0.04 = $1,000,000). Then discount that back to today using expected returns: $1,000,000 / (1.07)^30 ≈ $131,000 for a 30-year-old planning to retire at 60 with 7% real returns.

What return and withdrawal rate should I use?

A 4% withdrawal rate (the "4% rule") and 7% real return (based on historical S&P 500 returns after inflation) are common defaults. For a more conservative approach, use 3.5% withdrawal and 5% real return. Your personal risk tolerance and portfolio allocation should guide these choices.

What are the limitations of Coast FIRE?

Real returns vary year to year, and a poor sequence of returns early on can leave you short. The model assumes you can cover all living costs without touching investments. Healthcare, taxes, and lifestyle inflation aren't captured. Treat your coast number as a confidence-building checkpoint, revisit it every year or two, and keep a margin of safety.

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Coast FIRE Calculator

Understanding Coast FIRE

Coast FIRE Formula

How to Use the Calculator

Frequently Asked Questions

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