OddsRX • Free Betting Tool

Kelly Bet Size Calculator

Kelly Criterion is a staking formula that sizes a wager based on bankroll, odds, and estimated edge. Many bettors use fractional Kelly because full Kelly can be volatile.

← Back to all tools

Calculator

Kelly Bet Size Calculator

Free Tool

American odds

Your projected win probability (%)

Bankroll ($)

Kelly fraction (%)

Use 25 for quarter Kelly.

Full Kelly %—

Suggested stake—

Responsible-use note

OddsRX tools are for informational and educational purposes only. They are not financial, investment, legal, or gambling advice. Odds and probabilities do not guarantee outcomes or profits. Use responsibly and only where lawful.