Risk Management Tools
Five calculators that answer position size from five different angles: the basic risk math, the account-level cap, the mathematically optimal size, a stress test against a bad move, and a reusable reference table for next time.
Most traders size a position one of two ways: a rough guess, or a single rule they apply the same way every time regardless of how the setup actually looks. Position size isn't one number, it's the output of several separate checks: how many shares your risk per trade and stop distance allow, whether that's too much of your account in one name, what your actual edge says you should be sizing if you want to grow the account efficiently, and what happens to that position if the stock does something worse than your stop expects.
The five tools below aren't five separate topics. They're five views of the same decision, in the order most traders actually need them: size the trade from your risk, cap it against your account, check what the math says is optimal, stress-test it against a bad move, and build a table so you're not redoing this math on every single trade.
Before anything else, this is the number most traders actually use: given your account, your risk per trade, your entry, and your stop, how many shares can you buy without risking more than you meant to? Every other tool in this toolkit builds on getting this one right first.
Position Size Calculator →A trade can pass the risk-per-trade math and still be too concentrated, if the stop is wide enough that the position itself eats a large share of the account. This calculator checks the trade against a separate cap: the most you should ever put into one position as a percent of total account value.
Max Position Concentration Calculator →The Kelly Criterion takes your actual win rate and your average win-to-loss ratio and calculates the position size that theoretically grows an account fastest over a large number of trades. Most traders use a fraction of the full Kelly number rather than the raw output, but seeing the full calculation first shows exactly how aggressive or conservative your usual sizing really is by comparison.
Kelly Criterion Calculator →A stop-loss price is a plan, not a guarantee, gaps and fast moves can blow through it. This tool asks a different question: if the stock moved three times its normal daily range against you, all at once, how much would this position actually cost, and is that number one you could actually live with?
Volatility Stress Test Calculator →Once the first four checks make sense together, the last step is turning that math into something you don't have to redo from scratch on every trade. This generates a full reference table of position sizes across a range of stop distances for your account, so sizing a new trade becomes a lookup instead of a calculation.
Position Size Cheat Sheet Generator →None of these numbers is complete on its own. The basic risk-based size can still be too concentrated. The account cap doesn't tell you if you're sizing too small relative to your actual edge. The Kelly number assumes a stable win rate that real trading rarely holds exactly. And no stop distance survives every kind of move. Run all five together and you get a position size that's been checked from every angle that actually matters, not just the one you happened to think of first.