Find the amount you need invested today so that, with zero new contributions, it grows into your full retirement number on its own.
Filled in with example numbers. Replace them with yours.
Changes ahead that move your saving up or down, or add or take out a lump sum: a new job, a baby, a career break, an inheritance, a home down payment.
Includes your chapters.
| Per month | Coast FI at | Years away |
|---|
Your return, plus 1% and 2% either side. Each line stops where that return reaches Coast. Small changes in the return you assume move the answer a lot.
| Return | Coast number today | Coast FI at |
|---|
Full FI number spending ÷ withdrawal rate. Spending $50,000 a year at 4% means you need $1,250,000.
Coast FI number FI number ÷ (1 + return)years. It's the amount that grows into your FI number by retirement with no more contributions.
At $0 a month, you never catch up: your balance and your target grow at the same rate, so the gap stays the same size. Contributions are what close it.
Other retirement income lowers what your investments have to cover: (spending − income) ÷ withdrawal rate. If the income starts after you retire, the calculator adds a bridge: enough set aside at retirement to cover that income for the gap years, growing at your expected return.
Chapters change your monthly saving for a stretch of years, or add or take out a one-time amount. You save while you're below the Coast line and stop once you reach it. After that, saving less changes nothing, but money taken out still counts. If a withdrawal drops you back below the line, saving starts again until you're back.
Coast number with chapters is what you'd need today with no new saving, counting the chapters' one-time amounts and any withdrawals. Only count money you're confident about, like an inheritance that's certain.