Guide · Drawdown
The short answer
A 20% loss needs 25% to recover, a 50% loss needs 100%. The asymmetry is the whole argument for small size.
The reasoning is set out in full on the live site. In this build the article carries its position, the calculator that does the arithmetic, and the assumptions the answer depends on, so the structure and the internal linking can be reviewed before the prose is written.
What will not change is the shape: a claim in the first line, the method that supports it, the number it produces, and a link to the tool so a reader can put their own inputs in rather than take ours.