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Retirement

Coast FI Calculator

Find the amount that, left invested, grows to your retirement number on its own — and whether you're there yet.

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Your results will appear here.
Adjust the numbers, then press Calculate.

Assumptions
  • FI number = spending ÷ withdrawal rate. Real returns keep everything in today's dollars. Social Security and pensions aren't counted (they'd lower the number).

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Coast FI is a milestone many healthcare professionals find freeing. It's the point where your retirement savings, if left alone, will grow to everything you need by your planned retirement age. After that, your paycheck only has to cover today's life, not tomorrow's retirement. This calculator finds your Coast FI number and shows how close you are.

What this calculator does

Enter your yearly spending in retirement in today's dollars, a safe withdrawal rate, your current age, retirement age, retirement savings today and a real (after-inflation) return. The calculator shows:

  • your Coast FI number today,
  • your full retirement (FI) number,
  • where you are relative to Coast FI,
  • what your current savings would grow to with no new contributions, and
  • the age at which your current savings would reach FI on their own.

The formula in plain English

FI number = yearly retirement spending ÷ safe withdrawal rate. At 4%, that's 25 times your spending.

Coast FI number = FI number ÷ (1 + real return) raised to the number of years until retirement. It's the amount that grows into your FI number by then.

Projected savings = current savings × (1 + real return) raised to the years until retirement.

Coast age = the age when current savings alone would reach your FI number.

A worked example

Dr. Nguyen is 38, has $400,000 in retirement savings, and wants to retire at 62 spending $100,000 a year in today's dollars. She uses a 4% withdrawal rate and a 5% real return.

  • FI number: $100,000 ÷ 4% = $2.5 million.
  • Coast FI number today: about $775,000.
  • She's about 52% of the way to Coast FI.
  • With no new contributions, her savings would grow to about $1.29 million by 62.
  • Her current savings alone would reach FI at about age 75.6.

If she saves aggressively for about six more years, she'd likely reach Coast FI around her mid-40s, and could then choose to work part-time or in a role she enjoys more.

Why it matters at each career stage

If you're: Resident / fellow

Coast FI may feel far away in training, but small amounts saved now have decades to grow. Every $10,000 invested at 30 grows to about $43,000 in today's dollars by 60 at a 5% real return.

If you're: Employed

Many attendings reach Coast FI in their 40s with steady saving. Knowing your number can make career decisions less stressful: you can cut back clinical hours, step away from call or take a sabbatical without derailing retirement.

If you're: Practice owner

Practice owners often have uneven income. Reaching Coast FI with personal savings, separate from practice value, gives you security if the practice's value or income changes.

Using Coast FI wisely

Be honest about spending. Retirement spending often includes travel, healthcare before Medicare and helping family.

Use a conservative return. 4%–5% real is a reasonable planning range for a diversified portfolio.

Don't touch the money. Coast FI only works if you leave the savings invested.

Keep covering today. You still need income for current expenses, insurance and an emergency fund.

Revisit yearly. Market swings can move you closer to or further from Coast FI.

Beyond Coast FI

After Coast FI, there's "Barista FI" (savings cover most expenses, with part-time work covering the rest) and full FI (savings cover everything). Each milestone gives you more choice over how you work.

Next, find your full FI number, see how compound growth works, and estimate what going part-time would cost.

FAQ

Frequently asked questions

What does Coast FI mean?

It means you've saved enough that, with no more retirement contributions, your investments are expected to grow to your full retirement number by your target age. You still need to cover today's expenses, but you no longer have to save for retirement.

What is a safe withdrawal rate?

The share of your savings you can withdraw each year in retirement with a low chance of running out. 4% is a common rule of thumb for a 30-year retirement; a longer retirement may call for 3%–3.5%.

Why use a real return?

A real return is your return after inflation. Using it keeps all numbers in today's dollars, so your spending target doesn't need to be adjusted for future prices.

Should I stop saving once I reach Coast FI?

You could, but many people keep saving to retire earlier or build a cushion. Reaching Coast FI gives you options: part-time work, a career change or a lower-paying job you enjoy.

Does this include Social Security?

No. Social Security or a pension would lower the savings you need, so this estimate is conservative.

Keep going

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