Crypto Position Sizer

Workflow

Step 1: Determine Risk Percentage

Step 2: Calculate Dollar Risk

dollar_risk = initial_balance * risk_percentage

Step 3: Calculate Position Size

stop_distance = abs(entry_price - stop_loss_price)
stop_distance_pct = stop_distance / entry_price
position_size_usdt = dollar_risk / stop_distance_pct
contracts = position_size_usdt / entry_price

Step 4: Validate Against Constraints

1. Margin check: position_margin = position_size_usdt / leverage
   • Current total margin + new margin must be < 25% of current balance
2. Notional check: Current total notional + new position notional < 2x initial balance
3. Portfolio heat check: Sum of all position risk_% < 5%
4. If ANY check fails → reduce position size to fit or reject trade

Step 5: Round Down

Always round position size DOWN to nearest valid lot size for the pair. Never round up.

Step 6: Output

## Position Size: {PAIR}

- Risk: {risk_pct}% = ${dollar_risk}
- Entry: {entry_price}
- Stop-Loss: {sl_price} ({sl_distance_pct}%)
- Position Size: {size} contracts (${notional_value})
- Margin Required: ${margin} ({margin_pct}% of balance)
- R:R at TP: {ratio}

### Constraint Check
- [x] Risk per trade: {pct}% <= 3% max
- [x] Margin: {current + new}% <= 25% max
- [x] Notional: ${total} <= ${2x_initial} max
- [x] Portfolio heat: {total_heat}% <= 5% max

Key Principles

1. Never exceed HyroTrader limits — account loss is permanent
2. Default to 1%, upgrade to 1.5% only for A+ — consistency beats aggression
3. Round DOWN always — never round up on position size
4. Check all 4 constraints — any single breach = no trade
5. Half-Kelly philosophy — optimal growth with reduced risk of ruin