Coast FIRE Calculator (VND)
Coast FIRE is the moment your invested portfolio is already large enough that — even if you never contribute another dong — it will grow on its own to your full FIRE number by the time you retire. You still work to cover today's living costs, but you can stop saving for retirement and let compounding carry the existing balance the rest of the way. For a foreigner building wealth in Vietnamese dong, it is a powerful, concrete milestone: the day your future is funded and every salary after that buys present-day freedom.
It is not the same as full FIRE. Full FIRE means your portfolio is big enough to live off entirely — under the 4% rule from the Trinity Study, roughly 25× your annual spending. On 24.000.000 VND/month of expenses (288.000.000 VND/year), that full number is 7.200.000.000 VND. Coast FIRE is the same destination discounted back to today: you do not need 25× now, only enough that 25× will grow itself over the years you have left before retiring.
The younger you are, the lower the Coast FIRE threshold, because money has more years to multiply. Using an illustrative real return of 5%/year (already net of inflation), someone aged 28 aiming to retire at 55 — 27 years of runway — needs just 1.928.507.897 VND invested today. The calculator above takes your current age, target retirement age, annual expenses, expected real return and current invested balance, then tells you whether you have already crossed the Coast FIRE line.
One caveat governs the whole page: the 5%/year figure is an illustrative assumption, not a forecast of any market or fund, and not adjusted for Vietnamese taxes or fees. Real returns swing and can be negative for years at a stretch — treat the output as a planning scenario, not a guarantee.
How the calculator works
Step 1 — Your FIRE number from the 4% rule
The 4% rule (Trinity Study) suggests that withdrawing about 4% of a portfolio in the first year, then adjusting for inflation, has historically lasted a 30-year retirement. Inverted, the target is:
FIRE number = annual expenses × 25
| Symbol | Meaning |
|---|---|
| Annual expenses | Total yearly cost of living in retirement |
| 25 | The reciprocal of a 4% withdrawal rate (1 ÷ 0.04 = 25) |
Example: 288.000.000 VND/year × 25 = 7.200.000.000 VND.
Step 2 — Discount it back to today
Coast FIRE is the amount needed right now so that, with no further contributions, it compounds into the FIRE number by your retirement age:
Coast = FIRE number ÷ (1 + r)^n
where r is the expected real annual return (net of inflation, 5% = 0.05) and n is the years until retirement (retirement age − current age). Using a real return means the FIRE number is already expressed in today's purchasing power, so you do not have to forecast inflation separately.
Step 3 — Have you hit Coast FIRE?
The tool compares your current invested balance against the Coast FIRE threshold:
- If invested ≥ Coast you are coasting: you can stop saving for retirement and only need to earn enough to cover present-day expenses.
- If invested < Coast the tool shows the shortfall so you know how much more to build.
What the model leaves out
It assumes a constant real return across the whole horizon, ignores taxes and fees, and treats the 4% rule as a general benchmark rather than a personal guarantee. Spending in later life may differ from today. Re-run it across a range of returns — especially a scenario below 5% — to see how sensitive the threshold is.
Worked example: 24.000.000 VND/month, retire at 55
Illustrative assumptions: a constant 5%/year real return, 288.000.000 VND/year of expenses, and no contributions once Coast FIRE is reached. The full FIRE number is fixed at 7.200.000.000 VND.
| Current age | Years to retirement (age 55) | Coast FIRE needed today |
|---|---|---|
| 25 | 30 | 1.665.917.630 |
| 28 | 27 | 1.928.507.897 |
| 35 | 20 | 2.713.604.277 |
| 45 | 10 | 4.420.175.425 |
Read across: for the same retirement-at-55 goal, a 25-year-old needs 1.665.917.630 VND, while a 45-year-old needs 4.420.175.425 VND — far more, simply because there are fewer years for compounding to work. That gap is the quantitative case for starting early.
Have you hit Coast FIRE?
Suppose you are 28 with 500.000.000 VND invested. Your Coast FIRE threshold is 1.928.507.897 VND, so you have not yet hit Coast FIRE: you are short by 1.428.507.897 VND. Once your investments (plus any contributions) reach 1.928.507.897 VND, you can switch into coast mode.
After crossing the line you still need income for current living costs, but the pressure to save for the future lifts — that is the freedom Coast FIRE buys. To push on to full FIRE, pair this with FiMo's FIRE calculator and compound interest tool to plan steady contributions.
Frequently asked questions
What is Coast FIRE?
Coast FIRE is the point where your invested portfolio is large enough to grow into your full retirement number on its own, even if you stop contributing. You keep working to cover today's bills, but you no longer need to save for retirement. With 24.000.000 VND/month of expenses and an illustrative 5%/year real return, someone aged 28 retiring at 55 needs about 1.928.507.897 VND invested today.
How is Coast FIRE different from full FIRE?
Full FIRE means your portfolio can fund your entire life with no job — roughly 25× annual expenses under the 4% rule, or 7.200.000.000 VND on 288.000.000 VND/year of spending. Coast FIRE is that same target discounted to the present: you do not need 25× yet, only enough that it will compound into 25× by retirement. At 28 retiring at 55, Coast FIRE is just 1.928.507.897 VND — far below the full FIRE figure.
What is the Coast FIRE formula?
Two steps. Step 1: FIRE number = annual expenses × 25 (the 4% rule). Step 2: Coast = FIRE number ÷ (1 + r)^n, where r is the expected real annual return and n is the years to retirement. Verifiable example: 288.000.000 VND/year → FIRE number 7.200.000.000 VND; at age 28 retiring at 55 (n = 27, r = 0.05) → Coast = 7.200.000.000 ÷ 1.05^27 = 1.928.507.897 VND.
What return rate should I enter?
Enter a real return (net of inflation), not a nominal one. This page uses 5%/year as an illustrative assumption to keep the math easy to follow — it is not a forecast. Long-run real equity returns are often cited somewhere in the 4–7%/year range depending on the market and period, but past performance does not guarantee the future. Try a rate below 5% too, to see how sensitive the Coast FIRE threshold is.
Do I still have to work after reaching Coast FIRE?
Yes — Coast FIRE does not mean quitting. You still need income to cover current living costs (rent, food, transport, family). What changes is that you no longer have to save for retirement, because the money already invested will grow to the target by itself. Many people use this freedom to move to lower-paid but more enjoyable work, go part-time, or start a business.
Why is Coast FIRE easier when you are younger?
Because more years until retirement gives compounding more time to work, so the amount needed today is smaller. For the same retire-at-55 goal: at 25 you need 1.665.917.630 VND, at 28 you need 1.928.507.897 VND, and at 45 you need 4.420.175.425 VND — much more. Starting early is the single biggest advantage in reaching Coast FIRE.
Is the 4% rule reliable for the FIRE number?
The 4% rule comes from the Trinity Study, based on historical US market data and a roughly 30-year retirement. It is a widely used benchmark, not a guarantee: if you retire early and live longer than 30 years, or hit a bad market sequence right at the start, a safer withdrawal rate may be lower (3–3.5%). This page uses 25× (i.e. 4%) as the default; you can be more conservative by entering higher expenses to inflate the target.