Coast FIRE Calculator

Find when you can stop saving and let compound growth carry you to retirement

⚙ Your Details

Presets:

📈 Coast FIRE Results

⏳ Calculating...
FIRE Number $0 Spending / SWR
Coast FIRE Number $0 Invest this today, stop saving
Coast FIRE Age -- When you can stop contributing
Years of Saving Left -- Until coast status
Real Return Rate -- Nominal minus inflation
Monthly Savings Needed -- To reach coast target
Progress to Coast FIRE 0%

FIRE# = Spending / SWR
Coast# = FIRE# / (1+r)n
r = (1+nom)/(1+inf) - 1

Compare Scenarios

See how different return rates, retirement ages, and spending levels affect your Coast FIRE timeline.

Scenario A Conservative

FIRE #--
Coast #--
Coast Age--
Status--

Scenario B Moderate

FIRE #--
Coast #--
Coast Age--
Status--

Scenario C Aggressive

FIRE #--
Coast #--
Coast Age--
Status--

Investment Growth Projection

Watch your investments grow toward your FIRE number over time

Chart: growth chart.
Portfolio Growth Coast FIRE Line FIRE Number
📋

How to Use This Calculator

1

Enter Your Age

Input your current age and your target retirement age. The gap between these determines how long your money has to grow.

2

Add Your Investments

Enter the total value of your currently invested assets including 401(k), IRA, brokerage accounts, and other investments.

3

Set Return Assumptions

Choose your expected annual return rate and inflation rate. The calculator uses the real (inflation-adjusted) return for projections.

4

Define Retirement Spending

Enter your expected annual spending in retirement and your safe withdrawal rate (4% is the classic starting point).

5

Review Your Results

See your Coast FIRE number, coast age, and progress. Use the Scenario Analysis and Growth Chart tabs for deeper insight.

Formulas & Methods

V

inp.value.replace(/[^\d.]/g, '')

Real Return

(1 + nomReturn / 100) / (1 + inflation / 100) - 1

Fire Number

spending / (swrPct / 100)

Key Terms

Current AgeAn input parameter used in coast fire calculations. Adjust this value to see how it affects your results.
Retirement AgeAn input parameter used in coast fire calculations. Adjust this value to see how it affects your results.
Current Invested Assets ($)An input parameter used in coast fire calculations. Adjust this value to see how it affects your results.
Annual Return (%)An input parameter used in coast fire calculations. Adjust this value to see how it affects your results.
Inflation Rate (%)An input parameter used in coast fire calculations. Adjust this value to see how it affects your results.
Annual Spending in Retirement ($)An input parameter used in coast fire calculations. Adjust this value to see how it affects your results.

Real-World Examples

SA

Sarah

32-year-old marketing manager saving for her first home

Current Age
32
Retirement Age
32
Current Invested Assets ($)
15 A
Annual Return (%)
25%
Estimated total
$24,800

Try entering Sarah's values above to see the detailed breakdown.

Understanding Coast FIRE

What Is Coast FIRE?

Coast FIRE is a fundamental concept that this calculator helps you understand and apply. Whether you're a beginner or experienced professional, having precise calculations at your fingertips saves time and reduces errors.

Why It Matters

Understanding coast fire helps you make informed decisions backed by data rather than guesswork. Small miscalculations can compound into significant errors, making accurate tools essential for planning and analysis.

How It Works

The Coast FIRE Calculator applies established formulas and methodologies to your specific inputs. Results update in real-time, letting you experiment with different scenarios to find the optimal approach for your situation.

Tips & Best Practices

  • Start with realistic values — use actual data when available rather than rough estimates for more meaningful results.
  • Compare scenarios — try different input combinations to understand how each variable affects the outcome.
  • Save your work — use the Share button to bookmark specific calculations for future reference.
  • Consult professionals — for critical decisions, use calculator results as a starting point and verify with a qualified expert.
❓

Frequently Asked Questions

Basics What is Coast FIRE and how does it differ from regular FIRE?
Coast FIRE is the point where your existing investments will grow to your full FIRE number by retirement age without any additional contributions. Unlike regular FIRE where you need enough to retire immediately, Coast FIRE means you only need to cover current living expenses with your income — no more aggressive saving required.
Strategy What safe withdrawal rate should I use?
The 4% rule is the most commonly cited starting point, based on the Trinity Study. However, for early retirees with 40+ year horizons, many planners recommend 3.25–3.5%. If you plan to retire at a traditional age (65+), 4% is generally considered safe for a 30-year retirement.
Advanced Does the Coast FIRE number account for inflation?
Yes. The calculator uses the real return rate (nominal return minus inflation, via the Fisher equation) to discount your FIRE number back to today's dollars. This means your Coast FIRE number represents the amount you need in today's purchasing power.
Basics What happens after I reach Coast FIRE?
Once you reach Coast FIRE, you can stop contributing to investments and still reach your retirement target through compound growth. Many people use this milestone to switch careers, reduce work hours, pursue passion projects, or take a lower-paying but more fulfilling job.
Advanced How accurate are the growth projections?
The projections use a constant real return rate, which is a simplification. Actual market returns vary year to year. Use the Scenario Analysis tab to compare conservative, moderate, and aggressive assumptions. Real-world results will fluctuate, so consider these projections as directional guidance rather than guarantees.