Coast FIRE Calculator

How It Works

Enter your current age, target retirement age, expected annual investment return, and your retirement savings goal. The calculator divides your goal by the compound growth factor over the remaining years to find your Coast FIRE number — the amount you need invested right now. It then compares this to your current savings to show whether you have already reached Coast FIRE or how much more you need.

Example

If you want $1,000,000 by age 65, expect 7% annual returns, and you are currently 30, the Coast FIRE number is $1,000,000 / (1.07)^35 ≈ $93,663. If you already have $100,000 invested, you have passed your Coast FIRE number and could theoretically stop contributing to retirement.

When to use this calculator

• Use it to find out how much you need invested right now so compound growth handles the rest by retirement.
• Use it when considering a career change or reduced work schedule — to see if your savings can coast to your goal.
• Use it to compare different retirement ages and growth rate scenarios to find a plan that fits your risk tolerance.

The FIRE movement explained

• FIRE stands for Financial Independence, Retire Early — a strategy built on high savings rates, low expenses, and investment growth.
• The core principle is accumulating 25× your annual expenses (the 4% rule), then living off portfolio withdrawals.
• FIRE is not one-size-fits-all — your target depends on spending habits, risk tolerance, healthcare needs, and desired lifestyle.

Coast FIRE vs Lean FIRE vs Fat FIRE

• Coast FIRE: you have enough saved that compound growth will reach your retirement target — you stop contributing and just cover current expenses.
• Lean FIRE: you retire early on a minimal budget, typically under $40k/year in spending, requiring a smaller portfolio.
• Fat FIRE: you target a more comfortable retirement with higher annual spending ($100k+), requiring a significantly larger nest egg.

Investment assumptions and reality

• Calculators assume a constant annual return, but real markets fluctuate — some years gain 20%, others lose 30%.
• Inflation erodes purchasing power: a 7% nominal return with 3% inflation is only about 4% real growth.
• Fees matter — a 1% annual fund fee can reduce your final portfolio by 20–30% over decades compared to low-cost index funds.

Your path to coasting

• Calculate your Coast FIRE number, then compare it to your current invested assets to see how close you are.
• If you have not reached it yet, estimate how many more months of aggressive saving are needed at your current contribution rate.
• Once you hit the number, you can shift to lower-paying but more fulfilling work, reduce hours, or simply stop retirement contributions and redirect income to current-life goals.