Position Size Calculator
R-based sizing: risk a fixed % of your account per trade. This calculator converts that risk into the exact position size in both contracts and notional USD, so you never eyeball a position again. For deeper theory see our Kelly risk guide.
Account & trade
Sizing
How the math works
- Risk in USD = account_usd × (risk_percent / 100)
- Stop distance = |entry − stop|
- Position (contracts) = risk_usd / stop_distance
- Notional (USD) = position × entry
- Leverage used = notional / account
Rule of thumb: risk 0.5-1% per trade. Risking 5% means 20 losers in a row and you're down 64% · math does not care about how certain you felt going in.
Hypothetical result. Computed with hindsight from recorded prices or the numbers you entered; fees, slippage and funding only where a field says so; not a forecast, not a trade that was placed and not indicative of future results.
Questions
What is R-based position sizing?
You risk a fixed percentage of your account per trade. The calculator divides that risk in USD by your stop distance to get the exact position size in contracts and notional USD.
What risk percentage per trade is reasonable?
A common rule is 0.5-1% of the account per trade. Risking 5% per trade means 20 consecutive losses would draw the account down about 64%.
How is leverage derived here?
Leverage is an output, not an input: notional USD divided by account size. Size comes from risk and stop distance, and the leverage figure just follows.
Related
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