Advanced Coast FIRE Calculator
The quick calculator uses default assumptions. This one lets you control everything — your return rate, inflation expectations, withdrawal strategy, and even calculate for two.
Coast FIRE
Your Coast FIRE Projection
This chart shows two lines: your projected net worth (growing over time) and the Coast FIRE target (shrinking as retirement approaches). When they cross, you've hit Coast FIRE.
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How to Use This Calculator
Get your personalized Coast FIRE number in 4 steps:
Enter Your Basic Info
Start with your current age, target retirement age, and how much you've already saved. The calculator uses these to figure out how long your money has to grow.
Set Your Annual Expenses
How much do you plan to spend per year in retirement? Be realistic — include housing, healthcare, travel, and a buffer for surprises. This determines your target nest egg.
Adjust the Assumptions
This is where the advanced calculator shines. Tweak the investment return rate, inflation rate, and withdrawal rate. Not sure? Use the Optimistic or Conservative presets as starting points.
Read Your Results
Your Coast FIRE number appears instantly. The progress bar shows how close you are. The chart below visualizes when your net worth will cross the target line.
💡 Pro tip: Try both Optimistic and Conservative scenarios. If you're on track in both, you're in great shape.
Why Use the Advanced Calculator?
The quick calculator on the homepage is great for a first look. But real financial planning needs more control.
Test Different Scenarios
Markets don't always return 7%. What if returns are 5%? What if inflation hits 4%? The advanced calculator lets you stress-test your plan against different futures.
Plan as a Couple
Two people, two ages, two savings balances. Couple Mode handles the math — whether you want to combine everything or see individual numbers side by side.
Fine-tune Your Withdrawal Rate
The 4% rule isn't for everyone. If you're retiring early or want extra safety, you might use 3.5% or even 3%. This calculator lets you see exactly how that changes your target.
Frequently Asked Questions
7% is the standard for long-term stock market investing. Here's the math: S&P 500 has averaged about 10% nominal returns over the past century. Subtract 3% for inflation, and you get 7% real return.
If you're cautious, use 5%. If you're optimistic (or investing more aggressively), try 10%. The scenario presets let you compare both instantly — just click Optimistic or Conservative at the top of the calculator.
The two scenarios use different assumptions:
Optimistic: 10% return, 2% inflation, 4% withdrawal rate. This assumes strong market performance and low inflation — good for best-case planning.
Conservative: 5% return, 4% inflation, 3.5% withdrawal rate. This assumes weaker returns and higher inflation — good for stress-testing your plan.
If you're on track in the Conservative scenario, you're probably in good shape. Custom mode lets you set any values you want.
Toggle on Couple Mode to enter both partners' ages, retirement dates, and savings balances.
You'll see two calculation options: • Combined: Merges both savings accounts and uses the younger partner's timeline. This makes sense if you'll share expenses in retirement. • Separate: Shows individual Coast FIRE numbers side by side. Useful if you're tracking progress independently.
Most couples use Combined since they'll be splitting retirement costs anyway.
Higher inflation means you need more money. Here's why: if inflation averages 3%, $1 million today will only buy $412,000 worth of stuff in 30 years.
The calculator handles this by showing everything in today's dollars. Your Coast FIRE number is what you need today — the actual future amount will be higher, but it'll have the same purchasing power.
If you're worried about inflation, try the Conservative scenario (4% inflation) to see how it affects your target.
The quick calculator on the homepage uses fixed assumptions: 7% return, 3% inflation, 4% withdrawal rate. That's fine for a rough estimate.
But real financial planning needs flexibility. Maybe you want to see what happens with 5% returns. Maybe you're planning with a spouse. Maybe you want a more conservative withdrawal rate for early retirement.
This advanced calculator lets you test all of that. You can compare scenarios, adjust every parameter, and make sure your plan holds up under different conditions.
"It's not that I don't want to work hard—I just want to work hard for myself."
May you reach the shore soon 🌅