---
name: sizing-e8fce0a6f29e
description: "Position sizing with Kelly criterion and bankroll management"
emoji: "📐"
---

# Sizing - Complete API Reference

Calculate optimal position sizes using Kelly criterion, fractional Kelly, and portfolio-level allocation.

---

## Chat Commands

### Kelly Calculator

```
/kelly 0.45 0.55 10000              Market price, your prob, bankroll
/kelly "Trump 2028" 0.55 --bank 10k Calculate for specific market
/kelly --half 0.45 0.55 10000       Half Kelly (safer)
/kelly --quarter 0.45 0.55 10000    Quarter Kelly (conservative)
```

### Position Sizing

```
/size 10000 --risk 2%               Size for 2% risk per trade
/size 10000 --max-position 25%      Max 25% in single position
/size portfolio --rebalance         Rebalance to target weights
```

### Edge Calculation

```
/edge 0.45 0.55                     Calculate edge (prob - price)
/edge "Trump 2028" --estimate 0.55  Edge vs market price
```

---

## TypeScript API Reference

### Create Sizing Calculator

```typescript
import { createSizingCalculator } from 'clodds/sizing';

const sizing = createSizingCalculator({
  // Bankroll
  bankroll: 10000,

  // Kelly fraction (1 = full, 0.5 = half)
  kellyFraction: 0.5,

  // Limits
  maxPositionPercent: 25,
  maxTotalExposure: 80,
});
```

### Basic Kelly

```typescript
// Binary outcome (YES/NO market)
const size = sizing.kelly({
  marketPrice: 0.45,        // Current price
  estimatedProb: 0.55,      // Your probability estimate
  bankroll: 10000,
});

console.log(`Optimal bet: $${size.optimalSize}`);
console.log(`Edge: ${size.edge}%`);
console.log(`Kelly %: ${size.kellyPercent}%`);
console.log(`Expected value: $${size.expectedValue}`);
```

### Fractional Kelly

```typescript
// Half Kelly (recommended for most traders)
const halfKelly = sizing.kelly({
  marketPrice: 0.45,
  estimatedProb: 0.55,
  bankroll: 10000,
  fraction: 0.5,  // Half Kelly
});

// Quarter Kelly (very conservative)
const quarterKelly = sizing.kelly({
  marketPrice: 0.45,
  estimatedProb: 0.55,
  bankroll: 10000,
  fraction: 0.25,
});

console.log(`Full Kelly: $${sizing.kelly({...}).optimalSize}`);
console.log(`Half Kelly: $${halfKelly.optimalSize}`);
console.log(`Quarter Kelly: $${quarterKelly.optimalSize}`);
```

### Multi-Outcome Kelly

```typescript
// For markets with 3+ outcomes
const multiKelly = sizing.kellyMultiOutcome({
  outcomes: [
    { name: 'Trump', price: 0.35, estimatedProb: 0.40 },
    { name: 'DeSantis', price: 0.25, estimatedProb: 0.20 },
    { name: 'Haley', price: 0.15, estimatedProb: 0.15 },
    { name: 'Other', price: 0.25, estimatedProb: 0.25 },
  ],
  bankroll: 10000,
  fraction: 0.5,
});

for (const alloc of multiKelly.allocations) {
  console.log(`${alloc.name}: $${alloc.size} (${alloc.percent}%)`);
}
```

### Portfolio-Level Kelly

```typescript
// Optimal allocation across multiple markets
const portfolio = sizing.kellyPortfolio({
  positions: [
    { market: 'Trump 2028', price: 0.45, prob: 0.55 },
    { market: 'Fed Rate Cut', price: 0.60, prob: 0.70 },
    { market: 'BTC > 100k', price: 0.30, prob: 0.40 },
  ],
  bankroll: 10000,
  correlations: correlationMatrix,  // Optional
  fraction: 0.5,
});

console.log('Optimal Portfolio:');
for (const pos of portfolio.positions) {
  console.log(`  ${pos.market}: $${pos.size}`);
}
console.log(`Total exposure: ${portfolio.totalExposure}%`);
```

### Confidence-Adjusted Sizing

```typescript
// Reduce size when less confident
const size = sizing.kellyWithConfidence({
  marketPrice: 0.45,
  estimatedProb: 0.55,
  confidence: 0.7,  // 70% confident in estimate
  bankroll: 10000,
});

// Size is reduced proportionally to confidence
console.log(`Confidence-adjusted size: $${size.optimalSize}`);
```

### Edge Calculation

```typescript
// Calculate edge
const edge = sizing.calculateEdge({
  marketPrice: 0.45,
  estimatedProb: 0.55,
});

console.log(`Edge: ${edge.edgePercent}%`);
console.log(`EV per dollar: $${edge.evPerDollar}`);
console.log(`Implied odds: ${edge.impliedOdds}`);
console.log(`True odds: ${edge.trueOdds}`);
```

### Risk-Based Sizing

```typescript
// Size based on risk per trade
const size = sizing.riskBased({
  bankroll: 10000,
  riskPercent: 2,     // Risk 2% per trade
  stopLossPercent: 10, // 10% stop loss
});

console.log(`Position size: $${size.positionSize}`);
console.log(`Max loss: $${size.maxLoss}`);
```

---

## Kelly Fractions

| Fraction | Risk Level | Use Case |
|----------|------------|----------|
| **Full (1.0)** | Aggressive | Mathematical optimum, high variance |
| **Half (0.5)** | Moderate | Most traders, good balance |
| **Quarter (0.25)** | Conservative | New traders, uncertain edges |
| **Tenth (0.1)** | Very Safe | Learning, small edges |

---

## Edge Requirements

| Edge | Recommendation |
|------|----------------|
| < 2% | Don't trade |
| 2-5% | Small size (quarter Kelly) |
| 5-10% | Normal size (half Kelly) |
| 10%+ | Larger size, verify edge |

---

## Formulas

### Kelly Formula
```
f* = (p * b - q) / b

Where:
f* = fraction of bankroll to bet
p = probability of winning
q = probability of losing (1 - p)
b = odds received (1/price - 1)
```

### Edge Formula
```
Edge = Estimated Prob - Market Price
EV = Edge * Bet Size
```

---

## Best Practices

1. **Use fractional Kelly** — Full Kelly has too much variance
2. **Be conservative on edge** — Overconfidence kills accounts
3. **Account for correlation** — Don't over-expose to same theme
4. **Set max position** — Never more than 25% in one market
5. **Reassess regularly** — Edge changes as prices move


---
Source attribution: alsk1992
Original project: https://github.com/alsk1992/CloddsBot/blob/c930628c47a4a745f497e29035a3b64622f97cc7/src/skills/bundled/sizing/SKILL.md
License: MIT
License information: https://opensource.org/license/mit
Original upstream instructions; downloaded from Mega AI Hub.

## Upstream license notice

MIT License

Copyright (c) 2026 alsk1992

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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SOFTWARE.



# Mega AI Hub resource metadata

Creator / publisher: alsk1992
Original project: https://github.com/alsk1992/CloddsBot/blob/c930628c47a4a745f497e29035a3b64622f97cc7/src/skills/bundled/sizing/SKILL.md
Attribution basis: Source repository record

Fields of work: Finance & Accounting
Roles: Accountant, CFO / FP&A, Financial Analyst
Specialties: API
Tools: Clodds
Country applicability: Country not specified
Classification basis: Source catalog labels
Instruction SHA-256: 1f71c6c2e0b7472dfb021687c07797e716c3c8edbb9ea296370128d81cf54d40