CoastFIRE for Parents: Retirement vs College Savings

Picture this: you're 47, you've been dutifully maxing out your 401(k) for over a decade, and your oldest just started high school. College is four years away. Your youngest has six. You're staring at two 529 plans that feel perpetually underfunded while also wondering whether you'll ever actually be able to retire. Sound familiar?

Here's a question worth sitting with: what if your retirement savings had already done most of the heavy lifting, and you just didn't know it yet? That's the core idea behind CoastFIRE, and for parents in the thick of peak earning years, it might reframe the whole retirement-versus-college dilemma. Not by making the tension disappear, but by helping you see it more clearly.

CoastFIRE is a concept from the broader FIRE (Financial Independence, Retire Early) movement. The idea is straightforward: at a certain savings balance, compound growth alone could theoretically carry you to your full retirement number by the time you want to stop working, without you adding another cent.

At that point, you've hit your CoastFIRE number. You haven't retired. You haven't even slowed down necessarily. But your retirement may no longer need to be actively funded. Any income beyond living expenses could, in theory, go elsewhere.

For parents, "elsewhere" often means a college fund.

The math behind CoastFIRE rests on assumed long-term growth rates. A commonly discussed figure is around 7% annually in real (inflation-adjusted) terms, based on broad historical stock market averages, though this is not guaranteed and past performance doesn't predict future results. Your actual returns will vary depending on your asset allocation, market conditions, and timing. That's a crucial caveat to keep in mind throughout any CoastFIRE calculation.

Calculating your CoastFIRE number involves a few moving parts. Here's the general framework many people use, presented as a way to understand the concept rather than as a personalised financial plan:

1. Estimate your full retirement number. A widely referenced starting point is the 4% rule: multiply your expected annual retirement spending by 25. So if you anticipate needing $80,000 per year, your target might be around $2,000,000. For a deeper look at how this rule holds up today, safe withdrawal rate research in 2026 is worth reviewing.
2. Identify your target retirement age. The more years compound growth has to work, the lower your CoastFIRE number today. A 47-year-old targeting retirement at 65 has 18 years of runway. A 52-year-old has 13. Those seven years make a significant difference.
3. Work backwards using a present value calculation. If you need $2,000,000 at 65 and you're assuming a 7% nominal annual return (not inflation-adjusted for this version), you can use the present value formula: PV = FV / (1 + r)^n. For 18 years: $2,000,000 / (1.07)^18 equals roughly $596,000. That's the hypothetical CoastFIRE number for this scenario.
4. Compare that figure to what you've actually saved. If your retirement accounts are at or above that number, you may have technically hit CoastFIRE, under the assumed growth rate.

Again, these are illustrative calculations. Real returns fluctuate, fees matter, and sequence of returns risk (the danger of a bad market early in retirement) is real. A qualified financial adviser can help model scenarios specific to your situation.

Consider a hypothetical couple: Maria and David Garcia, both 47, with two kids aged 13 and 10. They've saved $580,000 across their 401(k)s and IRAs combined. They're aiming to retire at 65 and estimate they'll need about $75,000 per year in today's dollars.

Using a 4% guideline, their rough retirement target is $1,875,000. Working backwards with an assumed 7% nominal growth rate over 18 years, their hypothetical CoastFIRE number is approximately $560,000.

Their current balance of $580,000 puts them slightly above that figure, under those assumptions.

What might this mean practically? If the Garcias stopped contributing to retirement accounts entirely and their investments grew at that assumed rate (not guaranteed), compound growth could theoretically carry them to their target by 65. In this hypothetical, any additional savings they generate could potentially be redirected toward college costs, debt payoff, or other goals.

Does this mean they should stop contributing to retirement? Not necessarily. It's a thought experiment, not a plan. Factors like market downturns, inflation above expectations, healthcare costs, and changing retirement spending could all shift the picture significantly. But knowing they may be in CoastFIRE territory changes how they might think about trade-offs.

For comparison: if the Garcias were only 44 and had the same balance, their CoastFIRE number (21 years to 65 at 7%) would be roughly $459,000. They'd be well past it, with more flexibility. If they were 52 with only $350,000, their number would be approximately $752,000. They'd have meaningful ground to cover before reaching CoastFIRE and would likely want to keep prioritising retirement contributions.

Here's something financial planners frequently point out: your kids can borrow for college. You can't borrow for retirement. That's not a harsh sentiment. It's a structural reality of how the financial system works, and it shapes how many families end up prioritising their goals.

Student loans, work-study programmes, scholarships, community college pathways, in-state tuition options and family contributions can all play a role in funding higher education. Retirement has no equivalent safety net beyond Social Security, which the Social Security Administration itself notes is designed to replace only a portion of pre-retirement income. According to the SSA, Social Security replaces roughly 40% of pre-retirement earnings for average wage earners, though the actual amount varies.

This doesn't mean college planning gets ignored. It means the sequencing matters. For families who haven't yet reached their CoastFIRE number, many financial planners suggest a general approach of securing retirement contributions before fully funding college accounts. Once CoastFIRE is reached, the calculus shifts.

There's also a newer wrinkle worth knowing about: under SECURE 2.0 legislation, unused 529 plan funds can be rolled into a Roth IRA for the beneficiary, subject to conditions. Our post on the 529 to Roth IRA rollover rules walks through how this works. It means overfunding a 529 isn't quite the trap it used to be, which may give some families more flexibility to save aggressively for both goals.

For families actively weighing college and retirement savings, here are some of the factors commonly explored in financial planning conversations:

• Tax-advantaged accounts on both sides. A 529 plan grows tax-free for qualified education expenses. Meanwhile, a Roth IRA grows tax-free for retirement. Some families explore Roth IRAs as a dual-purpose vehicle because contributions (not earnings) can be withdrawn penalty-free, though using retirement accounts for education costs has long-term trade-offs worth discussing with an adviser.
• Catch-up contributions after kids leave home. Once college costs end, the financial picture often changes meaningfully. For those aged 50 and over, the IRS allows catch-up contributions of up to $8,000 to IRAs ($7,000 base plus $1,000 catch-up) and $30,500 to 401(k)s ($23,000 base plus $7,500 catch-up) in 2024. Ages 60-63 have an even larger catch-up opportunity under SECURE 2.0.
• The impact of part-time income. Some families find that reaching CoastFIRE opens the door to reducing work hours or switching to lower-stress employment while college bills are being paid. If retirement is theoretically on autopilot, income only needs to cover current living costs plus education expenses. This is related to what's often called BaristaFIRE, a semi-retirement approach worth understanding.
• Financial aid implications. Retirement accounts are generally not counted as assets in federal financial aid calculations (FAFSA), while 529 plans are. This is one reason some families choose to prioritise retirement savings in the years before college applications. The rules are nuanced, and a financial aid counsellor can help navigate this.
• Your savings rate still matters. Even if you've hit CoastFIRE, your overall savings rate shapes how much flexibility you'll have for education, emergencies, and life. Reaching CoastFIRE doesn't mean coasting on spending.

It's worth being honest about the limits of CoastFIRE thinking, especially for parents with a lot riding on the outcome.

Market returns are not guaranteed. Every CoastFIRE calculation assumes a steady growth rate. Real markets don't work that way. A prolonged downturn in the years just before or after retirement can dramatically change outcomes. This is known as sequence of returns risk, and it's one of the more underappreciated risks in retirement planning.

Healthcare costs are often underestimated. If early retirement or semi-retirement is part of the picture, coverage before Medicare eligibility at 65 can be expensive. It's a significant planning variable.

Life changes. Divorce, job loss, disability, or caring for aging parents can all alter a carefully constructed projection. CoastFIRE numbers should be revisited regularly, not treated as a fixed destination.

College costs are highly variable. Tuition inflation has outpaced general inflation for decades. What a four-year degree costs in 10 years is genuinely uncertain. Any college savings projection carries similar assumption risk to a retirement projection.

All of this points toward one conclusion: CoastFIRE is a useful lens, not a complete plan. It helps you ask better questions. A qualified financial adviser helps you answer them in the context of your actual household.

Disclaimer: This article is for general educational purposes only and does not constitute personalised financial, tax, or investment advice. Fidser is not a registered investment adviser or financial planner. All scenarios and calculations are hypothetical and illustrative only. Assumed growth rates are not guaranteed, and past market performance does not predict future results. Before making any decisions about retirement contributions, college savings, or investment strategy, please consult a qualified financial adviser who can assess your specific circumstances.