Your Coast FIRE number is the amount you need invested today so that, left alone with no further contributions, compound growth carries it to your full retirement goal by your target age. For a 30-year-old planning to retire at 65 with a $1.5 million goal, that number is roughly $272,000 at a 5% real return. Once you hit it, you can stop maxing out retirement accounts and just cover your current cost of living.
What Coast FIRE Actually Means
Coast FIRE is a variant of the Financial Independence, Retire Early movement, but it is far less extreme than traditional FIRE. Instead of saving 50–75% of your income to retire in your 30s, you front-load your retirement investing early, hit a calculated number, and then “coast” — meaning you stop adding new money to retirement accounts and simply earn enough to cover your living expenses until traditional retirement age.
The appeal in 2026 is obvious. The US personal savings rate sits at just 3.6%, mortgage rates remain above 6%, and most workers feel like they cannot save aggressively and live normally at the same time. Coast FIRE searches are up roughly 174% year-over-year because it offers a middle path: do the hard saving work once, early, then relax the pace without abandoning retirement entirely.
The Coast FIRE Formula
The calculation has three inputs: your target retirement number, your expected real rate of return, and the number of years until retirement.
Coast FIRE Number = Target Retirement Number ÷ (1 + real return rate) ^ years until retirement
To find your target retirement number, most people use the 25x rule: multiply your expected annual retirement spending by 25 (the inverse of a 4% safe withdrawal rate). If you plan to spend $50,000 a year in retirement, your target is $1,250,000.
Step-by-step calculation
- Estimate your annual retirement spending in today’s dollars — be specific, not aspirational.
- Multiply by 25 to get your full retirement number (based on a 4% withdrawal rate).
- Choose a real return assumption. Most calculators use 5–7% for a stock-heavy portfolio, net of inflation.
- Count the years until your target retirement age.
- Divide your retirement number by (1 + return)^years. That result is your Coast FIRE number — what you need invested right now.
Coast FIRE Number by Age: Real Examples
| Current Age | Retirement Target | Years to 65 | Real Return | Coast FIRE Number Today |
|---|---|---|---|---|
| 25 | $1,250,000 | 40 | 6% | ~$121,600 |
| 30 | $1,500,000 | 35 | 5% | ~$272,000 |
| 35 | $1,900,000 | 30 | 7% | ~$250,000 |
| 40 | $1,500,000 | 25 | 6% | ~$349,600 |
| 45 | $1,250,000 | 20 | 5% | ~$471,000 |
The pattern is stark: each five-year delay in reaching your number raises the required starting balance by roughly 25–30%, because there are fewer years left for compounding to do the work. A 35-year-old with $250,000 already invested at a 7% real return does not need to add another dollar to retirement accounts — that balance alone could grow past $1.9 million by 65.
How to Know You’ve Actually Hit Your Number
Reaching your Coast FIRE number is not just about the account balance — it also depends on whether your current income can realistically cover your living expenses without new retirement contributions. Check three things before declaring yourself “coasted”:
- Your invested balance matches or exceeds your calculated Coast FIRE number, not just your total net worth (home equity and cash reserves do not count for this calculation).
- Your household budget works without the retirement contribution. If you have been saving 20% of income and stop, does the remaining 80% still cover your life comfortably?
- You still have an emergency fund separate from retirement accounts. Coasting on retirement contributions does not mean skipping emergency savings — you still need 3–6 months of expenses in cash.
What to Do Once You’ve Coasted
Hitting your number does not mean you stop thinking about retirement — it means your investment contributions become optional rather than mandatory. Most people who reach Coast FIRE status redirect the freed-up cash flow toward a lower-stress or part-time job, a home down payment, or simply a higher standard of living today.
One thing worth keeping regardless: if your employer still offers a 401(k) match, keep contributing at least enough to capture it. The 2026 contribution limit is $24,500, with an $8,000 catch-up for those 50 and older. An employer match is free money you should not leave behind — the same logic applies if your employer ever pauses that match and you need to adjust.
Tracking Progress Without Linking Your Accounts
Most Coast FIRE calculators are one-time tools — you plug in numbers once and get a static answer. The harder part is tracking your actual invested balance against that target month over month, especially if you hold accounts across multiple brokerages and employer plans.
Tefteri lets you set a custom savings goal with pace tracking, so you can log your combined retirement balance periodically and see whether you are ahead of or behind your Coast FIRE timeline — without linking a brokerage account or sharing investment credentials. For anyone who wants a privacy-first way to check “am I coasting yet,” a manually updated goal is often simpler than juggling five different account logins.
Tefteri is a personal finance app for iPhone that helps you track expenses, income, and long-term savings goals — organized by category, stored locally on your device, and designed to make financial clarity effortless.
Frequently Asked Questions
What is a good Coast FIRE number for a 30-year-old?
It depends heavily on your target retirement spending and expected investment return, but a common range is $150,000–$300,000 invested by age 30, assuming retirement around 65 and a 5–6% real return. The exact figure changes significantly with your assumed retirement age and lifestyle — someone planning to retire at 55 needs a much larger number by 30 than someone planning to work until 67.
Is Coast FIRE realistic on an average salary?
Yes, more realistic than full FIRE. Coast FIRE does not require saving 50% of your income — it requires an intense saving period early on (often 15–25% of income in your 20s and early 30s) followed by a much lighter pace. Someone earning a median salary who maximizes retirement contributions for 8–10 years in their 20s can often reach a meaningful Coast FIRE number before other financial obligations, like a mortgage or kids’ expenses, increase.
Does Coast FIRE account for Social Security?
Most Coast FIRE calculators exclude Social Security to be conservative, since benefit levels depend on your future earnings history and policy changes decades out. If you factor in a conservative estimate, your actual required number is somewhat lower — but treat it as a bonus, not a load-bearing part of your plan.
What real rate of return should I use in the calculation?
Most planners use 5% to 7% for a stock-heavy portfolio, net of inflation. A more conservative planner might use 4–5% to account for fees, sequence-of-returns risk, and a more balanced asset allocation as you age. Running your calculation at two different return assumptions — one conservative, one optimistic — gives you a realistic range rather than a single fragile number.
What happens if I coast too early and I’m wrong about the math?
This is the biggest risk of Coast FIRE: stopping contributions based on assumptions that do not hold up, whether due to a market downturn or overly optimistic return assumptions. Recheck your invested balance against your target at least once a year, and resume contributing if a downturn or life change puts you meaningfully behind schedule. Coasting is a flexible strategy, not a one-time decision carved in stone.
