TradingCalcCrypto Position Size Calculator
RISK-BASED SIZING · PERPETUAL FUTURES · NEVER OVER-LEVERAGE
Calculate the correct position size from your maximum acceptable loss.
Position Side
How to use the position size calculator
- Enter your account balance in USDT.
- Set your risk percentage: the maximum you are willing to lose on this trade (recommended: 1–2%).
- Enter your entry price and stop loss price.
- Read the recommended position size: opening a position larger than this risks more than your limit.
Position size formula (risk-based)
The correct position size ensures your stop loss triggers before you lose more than your predefined risk amount:
- Max loss = accountBalance × riskPercent / 100
- Stop distance = |entryPrice − stopLossPrice| / entryPrice
- Position size = maxLoss / stopDistance
Position size is in notional USDT value (not margin). If your exchange uses leverage, the margin required = positionSize / leverage.
Worked example: SOL long, 1% risk
- Account: $5,000 · Risk: 1% · Entry: $150 · Stop loss: $142 · Leverage: 5×
- Max loss = $5,000 × 1% = $50
- Stop distance = ($150 − $142) / $150 = 5.33%
- Position size = $50 / 0.0533 = $938 notional
- Required margin = $938 / 5 = $187.50
You open a $938 SOL position using $187.50 in margin. If SOL drops to $142, your loss is exactly $50, 1% of capital. Without position sizing, traders often size by margin and accidentally risk 10–20% per trade.
Why the stop loss comes first
Position sizing is the opposite of how most beginners approach trading. Most traders decide how much to trade, then set a stop. The correct order: decide maximum acceptable loss, then find a technically valid stop loss level, then calculate position size from those two inputs. This separates risk management from price prediction and keeps losses consistent regardless of volatility.
Once you have a position size, check the Liquidation Calculator at your chosen leverage, or use the Max Safe Leverage Calculator to confirm that leverage is appropriate for the asset's volatility. If that size is large relative to the order book, check the real execution cost with the Order-Book Impact Calculator.
Run a full pre-trade risk check
Position size is one input. Before opening a trade, combine it with liquidation distance and funding cost in a single workflow:
Run Pre-Trade Risk Check →Use via API or MCP
Every calculation on this page is available as a deterministic API call. Plug exact position sizes into trading bots, risk dashboards, or AI agents: no approximations, no rounding surprises.
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What assumptions and edge cases does this calculator use?
Entry price, stop loss and the amount you risk must be above zero, leverage is above zero (default 1), and fees are fractions from 0 to 0.05. A combination of fees and prices that leaves no risk per unit is refused. Not covered: slippage past the stop, funding, your exchange lot size rounding and whether you have the margin.
What is position sizing in crypto trading?
Position sizing determines how much of your capital to risk on a single trade. Proper sizing protects your account from large losses. Most professional traders risk 1-2% of capital per trade.
How do I calculate position size from risk?
Divide your max acceptable loss by the distance to your stop loss (as a fraction of entry price), then multiply by leverage. This calculator does it automatically.
What's the 1% rule in trading?
Never risk more than 1-2% of your total capital on a single trade. If your account is $10,000, maximum loss per trade = $100-200. This rule preserves capital during losing streaks.
How does stop loss distance affect position size?
A tighter stop allows a larger position for the same risk amount. A wider stop requires a smaller position. Always set stop loss first, then calculate position size.