Position Sizing Guide — Calculate Optimal Trade Size with Smart Money Data
Master position sizing. Calculate exact trade sizes using risk percentage, Kelly criterion, and whale confidence metrics.
Why Position Sizing Determines Success
Trading system accuracy matters less than position sizing. A trader with 55% win rate + proper sizing beats 75% win rate trader with wrong sizing. Most losses come from over-sizing winners and under-sizing losers.
Smart Money API enhances sizing by providing whale conviction scores—helping you size bigger on fortress setups and smaller on weak signals.
Fixed Risk Method (Conservative)
Risk fixed percentage per trade (1-2% recommended):
Account Size: $50,000
Risk % per trade: 1%
Max loss per trade: $500
Setup: BTC at 43,000, stop at 42,500 (loss = $500)
Stop distance: 500 USD or 1.16%
Position size: ($500 / 500) = 1 BTC
Formula: Position Size = (Risk Amount / Stop Distance)
This guarantees you never lose more than your preset amount. Use 1-2% for normal trades, 0.5% for low-conviction setups.
Turn this guide into numbers. Model liquidation levels, funding drag and hedge ratios with live derivatives data — free to start.
Model your risk free →Kelly Criterion Method (Advanced)
Optimal sizing based on win rate and R:R ratio:
Kelly % = (Win% * AvgWin - Loss% * AvgLoss) / AvgWin
Example: 65% win rate, 2:1 R:R
Kelly = (0.65 * 2 - 0.35 * 1) / 2
Kelly = (1.30 - 0.35) / 2 = 0.475 = 47.5%
Conservative Kelly: Use 25% of Kelly (0.475 * 0.25 = 11.9%)
Position size: Account * 11.9% = $50k * 0.119 = $5,950
This sizes optimally while managing drawdown risk.
| System Win Rate | Avg R:R | Full Kelly | Safe Kelly (25%) |
|---|---|---|---|
| 55% | 1.5:1 | 12.5% | 3.1% |
| 60% | 2.0:1 | 35% | 8.75% |
| 65% | 2.5:1 | 52.5% | 13.1% |
Pro tip: Use 25% of Kelly to avoid catastrophic drawdowns. Most professional traders use 15-25% Kelly sizing.
Smart Money-Enhanced Sizing
Adjust Kelly sizing up or down based on whale conviction:
// Get whale conviction score
GET /whale-confidence?symbol=BTC&setup_type=support_bounce
Response:
{
"confidence_score": 0.82, // 82% whale conviction
"sizing_multiplier": 1.3, // 30% larger position
"base_kelly_size": 5,
"adjusted_size": 6.5 // Position increased 30%
}
Position sizing logic:
- High whale conviction (>0.75): Use 125-150% of Kelly
- Medium whale conviction (0.60-0.75): Use 100% of Kelly
- Low whale conviction (<0.60): Use 50-75% of Kelly
This lets you capitalize on fortress setups (where whales positioned) while protecting on weak setups (where uncertainty high).
Position Sizing Checklist
- Define maximum loss per trade (1-2% account)
- Calculate stop distance precisely
- Use Kelly criterion for optimal sizing
- Adjust for whale conviction (25-150% of Kelly)
- Never exceed maximum account risk
- Scale down in drawdown periods
- Track actual win rate and adjust sizing quarterly
Smart Position Sizing Calculator
Access Pro plan for automated position sizing with whale conviction adjustment.
Upgrade to Pro