Calculate exact share or contract size from your account risk and stop distance.
How this is calculated
Risk amount = account balance × (risk percentage ÷ 100)
Stop distance = |entry price − stop-loss price|
Stocks: shares = floor(risk amount ÷ stop distance); position value = shares × entry price
Futures: ticks at risk = stop distance ÷ tick size; risk per contract = ticks at risk × tick value; contracts = floor(risk amount ÷ risk per contract)
Forex: pips at risk = stop distance ÷ pip size; lots = risk amount ÷ (pips at risk × pip value per standard lot)
Worked example
Account balance $25,000.00, risk 1%, entry $182.40, stop $179.90.
Risk amount = 25,000 × 0.01 = $250.00.
Stop distance = 182.40 − 179.90 = $2.50.
Shares = floor(250 ÷ 2.50) = 100 shares, a position value of $18,240.00.
Understanding position sizing
Position sizing is the arithmetic step that connects a stop-loss level to the number of shares, contracts or lots a position holds. The inputs are an account balance, the percentage of that balance a trader has decided to expose on a single idea, and the distance between entry and stop.
Because size is derived from stop distance, a wider stop produces a smaller position and a tighter stop produces a larger one for the same cash risk. That relationship is mechanical, not predictive: it describes what the position costs if the stop is reached, not how likely that is.
Instruments differ only in how the stop distance is converted to cash. Shares use the price distance directly, futures convert it into ticks and multiply by tick value, and forex converts it into pips and multiplies by the pip value of a standard lot.
Slippage, commissions and gaps mean the realised loss can exceed the calculated risk amount. Minimum increments — whole shares, whole contracts — also force rounding down, so the executed size is usually slightly smaller than the raw output.
Frequently asked questions
What risk percentage should I enter?
That is a personal decision defined by your own trading plan or, for funded accounts, by your firm's rules. The calculator applies whatever percentage you enter and does not recommend a value.
Why are shares and contracts rounded down?
Both trade in whole units. Rounding down keeps the position at or below the cash risk you specified rather than above it.
Does the result account for commissions and slippage?
No. The output is the raw arithmetic size implied by your inputs. Fees, spread and slippage are additional costs that can make the realised loss larger than the calculated risk amount.
Why does a tighter stop produce a larger position?
Cash risk is held constant, so dividing the same risk amount by a smaller stop distance yields more units. The dollar risk is unchanged; only the unit count moves.
Which pip size do JPY pairs use?
Yen-quoted pairs conventionally use 0.01 as the pip size rather than the 0.0001 used by most other pairs. Change the pip size field on the Forex tab accordingly.