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About Position Size Calculator Online
This tool calculates how many shares, contracts, or lots to trade based on your account size, the maximum percentage of capital you're willing to risk per trade, and the distance between your entry and your stop-loss. The result is the largest position you can take that still respects your risk rules if the stop is hit.
Position sizing is the single most important risk control in active trading. Profitable strategies fail when a single oversized loss erases months of gains. Sizing every trade by your stop distance instead of by gut feeling enforces consistent risk per trade and protects the account from disaster.
Use it before placing any trade, especially when entering a market with unfamiliar volatility — currencies, futures, options, or volatile small-cap stocks.
How to use this tool
How to size a trade based on risk and stop distance
Account size and risk
"Account size" is your trading capital. "Risk % of account" is the slice you're willing to lose on this idea (0–100; common values are 0.25–2%). Negative or > 100 throws a clear error.
Stop distance in price units
"Stop distance (price units)" is how far from entry your stop sits, in the instrument's price units (dollars for stocks, pips for FX expressed as price, ticks for futures). Sign doesn't matter — the absolute value is used.
Pick the contract step
"Contract step" decides how the position is counted: Single unit (1 share/coin/contract), Micro lot (1,000 base units), Mini lot (10,000), Standard lot (100,000), or Custom. Custom mode requires "Custom units per increment".
Press Run
Result returns positionSize (in base units), riskAmount (account × risk%, in currency), unitsPerIncrement (the resolved step size), and incrementCount (how many lots/contracts to enter).