What Is Coast FIRE? The Lazy Path to Early Retirement

Coast FIRE is the idea that once your investments reach a certain size, you can stop making retirement contributions entirely and simply "coast" to your retirement goal — letting compound interest do all the heavy lifting from that point forward.

The math behind it is surprisingly powerful. If you have enough invested today, and you leave it alone for 20, 30, or 40 years, the market's historical average return (~7-10% annually) will grow that balance to your full retirement number on its own. No more contributions required. You just need to cover your living expenses in the meantime.

To calculate your Coast FIRE number, you work backwards from your retirement target. Start with your FIRE number (typically 25x your annual spending, based on the 4% withdrawal rule). Then discount that number back to today using your expected rate of return. The result is what you need invested right now to coast to retirement.

For example, if you want $1.5 million at 65 and you're currently 35, and you expect a 7% real return: you need about $393,000 invested today. Once you hit that number, you could technically stop contributing and still reach $1.5M by 65 — even if you never add another dollar.

This is why Coast FIRE is so popular: it's achievable much earlier than full FIRE. You don't need to be a high earner or an extreme saver. You just need to start early enough that compounding does the work for you.

The real-world implication is significant. Once you hit Coast FIRE, you only need to earn enough to cover your current expenses — not save for retirement on top of them. That dramatically reduces your income requirements and gives you career flexibility, the ability to take lower-stress jobs, or transition to work you actually enjoy.

The biggest risk with Coast FIRE is sequence-of-returns: a major market downturn early in your "coasting" period can extend your timeline. Most financial planners suggest building a buffer of 10-15% above your strict Coast number before truly stopping contributions.

One underrated move: even after hitting Coast FIRE, small contributions make a meaningful difference. Even $100-200 a month after hitting your Coast number can shave years off your timeline or add significant cushion against bad market stretches.

The most important thing about Coast FIRE is starting early. The earlier you hit your Coast number, the longer compounding works for you — and the less you ultimately need to save. Time is the single most powerful variable in the equation.