Useful whenever you need to know how big a slice is: how much of your account one position uses, or what share of the month's result came from a single trade.
A position worth 45 inside a 180 account uses 45 ÷ 180 × 100 = 25% of it.
All nine calculators are also in the Growstones app for iPhone and Android — alongside position sizing, a growth simulator and a weekly journal. Your data stays in your iCloud.