Trading Risk and Position Size Calculator
A simple, private calculator that turns your risk rules into numbers: how much capital you are putting at risk, how far your stop sits from entry, and an illustrative position size. Everything runs in your browser — nothing you type is sent or stored.
Deciding position size is one of the most important parts of risk management. This tool applies the common approach of risking only a small, predefined portion of an account on any single idea, then working backwards to an illustrative size based on the distance to your stop. It is a mathematical illustration, not a recommendation.
Calculate your risk
Bring structure to every decision
Position sizing is one part of a considered approach. Mallee Capitholm combines market perspective with AI-assisted insight. Trading involves significant risk.
Explore Mallee CapitholmThe formula and assumptions
The calculator uses a standard risk-based sizing method:
Stop-loss distance = | Entry price − Stop-loss price |
Estimated position size = Maximum capital at risk ÷ (Stop-loss distance × value factor)
Exposure % = (Position value at entry ÷ Account value) × 100
Assumptions: the value factor defaults to 1 when left blank, meaning one unit of price movement equals one unit of currency per unit held. For instruments with contract sizes, lot conventions, currency conversion or tick values, enter the appropriate factor — otherwise the size shown will not match your instrument.
Why real position sizing is more involved
This tool deliberately keeps things simple. In practice, the size you can and should trade also depends on the instrument, its contract or lot size, the account currency and any conversion, the spread, likely slippage, financing costs, and your provider’s specific terms. Leverage changes how much capital is required and how quickly losses accumulate. Treat the output as a starting point for thinking, not a final answer.
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- U.S. Securities and Exchange Commission — investor education: investor.gov
- Financial Conduct Authority — consumer information: fca.org.uk