Position Size Calculator
Determine the correct position size from your risk amount, entry, and stop loss — the foundation of trade risk management.
Enter values and calculate to see results here
How the Position Size Calculator works
Formula
quantity = risk_amount / |per_quantity_risk|, where per_quantity_risk = |direction × (entry - stop_loss) × contract_size| for linear.
Example
EURUSD BUY at 1.0850, SL at 1.0800, risk $500, linear: per_unit_risk = $50, quantity = 0.10 lots
Inputs & units
Direction, entry, stop loss, risk amount (in the instrument's profit currency), and formula. Result includes mathematical and tradable quantity with volume validation.
Supported formulas
Linear (forex, stocks, indices), Futures tick value (futures), Inverse (crypto contracts).
Limitations
Gross P&L only. Spread, commissions, slippage, swap, funding, leverage, and margin are excluded. Quantity may be capped at volume_max or rounded to volume_step.
Metadata source
Contract specifications (contract_size, tick_size, tick_value, quantity_unit, profit_currency, volume rules) are sourced from the AlgoVistra instrument database.
This tool is for educational purposes only and does not constitute financial advice. Calculations are deterministic and do not account for market conditions, execution costs, or account-specific parameters.
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Open toolFrequently asked questions
How is position size calculated?
The tool divides your risk amount by the per-unit risk (from entry to stop loss), then adapts for the instrument's contract size and quantity unit.
What if I don't have instrument metadata?
The tool will still calculate a basic result, but selecting a specific instrument provides more accurate sizing for contract size and unit type.