Trading Instruments · Educational Tools
Calculators, grounded in the books.
Three tools built from real trading-book fundamentals. Not investment advice; every number here is yours to set.
Position size calculator
How many shares to buy so a single trade never risks more than you've decided in advance. Set your stop-loss first — the position size follows from it, not the other way round.
Account size $100,000
Risk per trade % of account2.0%
0.1%2.5%5%7.5%10%
Entry price
Stop-loss price
Position size
$ at risk
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Capital deployed
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Where the % goes if this trade loses
Stop distance vs. account risk, drawn to scale.