Coast FIRE explained

Coast FIRE is the point where an existing retirement portfolio is modeled to reach its later target through growth alone, without additional retirement contributions.

Discount the future target

Begin with a retirement spending target and withdrawal rate, then discount that portfolio amount back to today using years until retirement and an assumed real return.

Time does the heavy lifting

The threshold is especially sensitive to age. More years allow more compounding; delaying the calculation by several years can require a much larger current balance.

What changes after the threshold

Some people reduce contributions, change careers, or prioritize other goals. Current living expenses still require earned income or other resources.

Build a margin

Returns do not arrive smoothly, and future spending is uncertain. Continuing some contributions or targeting a later retirement date can provide room for error.

Primary source

SEC Investor.gov: saving and investing basics