Free calculators
Tools
Built around the rules prop firms actually enforce. Nothing to sign up for; everything runs in your browser.
Futures position sizer
Contracts per trade that keep one loss inside your chosen share of the remaining drawdown.
Trailing drawdown calculator
Where your floor sits now, how much room is left, and when it stops trailing. With an EOD vs intraday chart.
Consistency rule checker
Paste your daily P&L and see whether you meet a firm's best-day rule, and how much more profit you need if not.