Free trading risk calculators

Four calculators covering the arithmetic that actually decides whether a strategy survives: how much to buy, whether the edge is real, whether the position size will destroy you, and how bad a normal losing run gets.

No signup, no limits, nothing stored. Each runs entirely in your browser.

• Position size calculator

  How many units to buy so that hitting your stop costs a fixed, chosen percentage of the account — never more.

  Answers: How much should I buy?

• Expectancy calculator

  Whether a strategy makes money at all, plus the win rate it would need to break even at your reward-to-risk.

  Answers: Does this actually have an edge?

• Risk of ruin simulator

  Monte Carlo over thousands of trade sequences, showing how often your position size ends the account.

  Answers: Will my position size blow me up?

• Losing streak simulator

  The longest run of losses your win rate actually predicts, so an ordinary drawdown does not look like failure.

  Answers: Is this losing run normal?