Finance

Coast FI Calculator

Find out whether you've already saved enough to coast to retirement on a lighter income — or exactly when you will.

Timeline

Current age

Retirement age

Savings

Current invested savings

Retirement and brokerage accounts — not home equity or cash reserves.

Monthly contribution

Set to $0 to check whether you could already stop contributing.

Assumptions

Expected annual return

Use an inflation-adjusted (real) return — long-run US stock returns average roughly 6-7% real.

Safe withdrawal rate

4% is the traditional rule of thumb; some use 3-3.5% for extra margin.

Desired annual retirement spending

In today's dollars — this calculator works entirely in today's purchasing power.

Result

Coast FI number — what you need invested today

$130,105

At this contribution rate, you're projected to reach Coast FI at age 58 — after that you could stop saving for retirement entirely and still hit your number by age 65.

Your progress toward Coast FI: 38%
FI number (target portfolio at 65): $1,000,000
Projected value at 65 (with contributions): $1,052,913
Projected value at 65 (if you stopped today): $384,304
Years to retirement: 35

A planning estimate, not a guarantee — real markets don't return a steady rate every year, and this doesn't account for taxes, Social Security, or changes to your spending goal over time.

How this works

This starts from your desired retirement spending and safe withdrawal rate to find your FI number — the portfolio you'd need to retire on. It then works backward: how much would you need invested today for compounding alone to reach that number by your retirement age? That's your Coast FI number. If your current savings already clear it, you're coasting. If not, it simulates your savings year by year — including your monthly contributions — to find the age you're projected to cross that line, since the bar itself moves as retirement gets closer.

FAQ

What is Coast FI?: Coast FI (Coast Financial Independence) is the point at which your current invested savings, left alone to grow, will reach your retirement number by your target retirement age — without any further contributions. You'd still need income to cover today's living expenses, but you could stop saving specifically for retirement and let compounding do the rest.
How is the Coast FI number calculated?: First, this finds your FI number — the portfolio size needed to sustain your desired spending using your safe withdrawal rate (spending ÷ withdrawal rate). Then it discounts that number back to today using your expected return over the years remaining: Coast FI number = FI number ÷ (1 + return)^years. If your current savings meet or exceed that discounted number, you've already coasted.
Why does this use a real (inflation-adjusted) rate of return?: Working in real terms means every number in this calculator — your savings, your spending goal, your projections — is expressed in today's purchasing power, so you don't have to separately guess at future inflation. If you'd rather use a nominal return, also increase your spending goal each year by your assumed inflation rate to keep the comparison fair.
What doesn't this calculator account for?: Real markets don't return a steady percentage every year — sequence-of-returns risk means a bad stretch early in retirement can matter more than the long-run average. It also doesn't factor in taxes, Social Security or pension income, healthcare costs (which often outpace general inflation), or a spending goal that changes over time. Treat the result as a directional estimate, not a guarantee.