What is Coast FIRE
Coast FIRE is an intermediate milestone in the FIRE movement. The core idea:
Once your assets reach a certain threshold, even if you stop contributing new money today, the long-term compound growth of what you already have will reach your retirement target by your planned retirement age.
Someone who has hit Coast FIRE cannot retire today — they still need income to cover daily expenses. But they no longer need to save specifically for retirement. It's a state of "you can switch to a lower-stress job, stop saving, and do what you actually want to do."
How to calculate Coast FIRE
The formula has two steps.
Step 1: Calculate the retirement target
This follows the 4% withdrawal rate approach:
Retirement assets needed = Annual expenses ÷ withdrawal rate
Example: expect to spend NT$600,000 per year in retirement, using a 4% withdrawal rate:
- Retirement assets needed = 600K ÷ 0.04 = NT$15,000,000 (15M)
Step 2: Discount back to today
If you have N years until retirement and expect an annualized return of r%, discount the retirement target back to today:
Coast FIRE number = Retirement target ÷ (1 + r)^N
Example: using the NT$15M target above, you're 30 now and plan to retire at 65, assuming 5% annualized returns:
- N = 35 years
- Coast FIRE number = 15M ÷ (1.05)^35 ≈ NT$2,720,000
That means if you have NT$2.72M invested today, even if you contribute nothing more, 35 years of 5% compounding gets you to NT$15M.
Why this concept is useful
Traditional FIRE emphasizes reaching "full financial independence" as fast as possible. But for most people, accumulating NT$15M–25M to retire immediately is a long slog that requires an uncomfortably high savings rate.
Coast FIRE provides an intermediate milestone:
- Early high-savings years have the highest return on effort — compounding time is longest
- Once you pass the threshold you can let go — a clear psychological marker
- Career options open up — after hitting Coast FIRE you can accept lower-paying but more interesting work, as long as it covers daily expenses
Taiwan-specific considerations
The Coast FIRE math doesn't depend on country, but a few local adjustments are worth thinking about.
Labor Insurance (勞保) and Labor Pension (勞退)
Taiwan's Labor Insurance old-age pension and Labor Pension (6% employer + optional self-contribution) provide retirement income. Factoring them in reduces the "personal investment assets" needed, which in turn lowers the Coast FIRE threshold. For Labor Insurance estimates see the Bureau of Labor Insurance website; for Labor Pension, check your individual retirement account.
National Health Insurance and medical costs
Taiwan's National Health Insurance covers basic medical care and remains affordable in retirement, but self-pay items (private rooms, advanced treatments) still require a buffer. This affects your "annual expenses" figure.
Inflation assumption
The Trinity Study and similar US research assume roughly 3% inflation, but Taiwan's actual inflation over the past decade has been 1–2%. The inflation assumption materially shifts results — using 3% makes the Coast FIRE threshold look much higher than using 2%.
Currency risk
If you hold mainly US stocks and bonds, converting back to TWD for retirement spending adds exchange-rate risk. This variable is often overlooked in localized calculations.
Using the winpie tool
The Coast FIRE calculator on this site runs the above formula live. You can adjust withdrawal rate, annualized return, current assets, and monthly contributions to see the corresponding Coast FIRE threshold and time to reach it.
One caveat: Coast FIRE is fundamentally a scenario calculation, not a prediction. Real returns fluctuate, and both markets and personal circumstances change. Treat it as a conceptual milestone or a thinking tool, not a precise target.