Free trading calculators
Small, honest tools for the arithmetic behind a trade — sizing, risk, and compounding. Free, no sign-up, no account. They tell you what a rule should do; when you want to know whether a strategy actually beats buying and holding on real data, that's what the backtester is for. Sizing and risk come first — the groundwork before you ever test.
By using these calculators, you agree to our Terms of Use and Disclaimer. Results are hypothetical and educational — not investment advice. You decide and execute on your own broker.
How many shares or units to buy so a losing trade costs only what you decided to risk.
Open the calculator →Your reward-to-risk on a trade — and the win rate you'd need just to break even at it.
Open the calculator →Score a trade in R, and turn a win rate and average win/loss into an expectancy per trade.
Open the calculator →The gain you need to climb back from a loss — and why deep drawdowns are so punishing.
Open the calculator →Grow a starting balance at a periodic return, with optional contributions — see compounding work.
Open the calculator →Net profit or loss on a long or short trade — after fees — in dollars and as a return.
Open the calculator →Your new average price after buying more, and the move it takes to get back to break even.
Open the calculator →The bet size an edge mathematically justifies — and why most traders use a fraction of it.
Open the calculator →Monte-Carlo odds of blowing up: how bet size and edge decide whether variance wipes you out.
Open the calculator →Return earned per unit of risk, versus just holding cash — the standard risk-adjusted score.
Open the calculator →How many trades before an edge is more than luck — a floor to clear, never proof it works.
Open the calculator →A calculator shows what a rule should do on paper. Whether a strategy actually beats simply buying and holding — costs on, losses shown, no hindsight — is a different question, and the only one that pays. Test one on real data, free, no sign-up.