Kelly Criterion Calculator

Calculate optimal bet size using the Kelly Criterion for trading & options. Enhance your strategy with our authoritative and accessible tool.

Full original guide (expanded)

Kelly Criterion Calculator

Estimate the optimal bet fraction using the Kelly Criterion from win probability and win/loss ratio.

Interactive Calculator

Results

Optimal Bet Size 0%

Data Source and Methodology

All calculations are based on the standard Kelly Criterion formula as detailed in financial literature. For more information, consult authoritative sources such as academic papers and financial textbooks. All calculations strictly adhere to these sources.

The Formula Explained

\[ f^* = \frac{bp - q}{b} \]

Where:

  • \( f^* \) is the fraction of the current bankroll to wager;
  • \( b \) is the odds received on the bet;
  • \( p \) is the probability of winning the bet;
  • \( q \) is the probability of losing the bet (1-p).

Glossary of Terms

  • Win Probability (%): The estimated probability of a successful outcome.
  • Win/Loss Ratio: The ratio of the amount won to the amount lost per bet.
  • Optimal Bet Size: The calculated percentage of the bankroll to wager.

How It Works: A Step-by-Step Example

Suppose you have a win probability of 60% and a win/loss ratio of 2. Using the Kelly Criterion formula, the optimal bet size is calculated as follows:

\[ f^* = \frac{(2 \times 0.6) - 0.4}{2} = 0.4 \]

This means you should bet 40% of your bankroll.

Frequently Asked Questions (FAQ)

What is the Kelly Criterion?

The Kelly Criterion is a mathematical formula used to determine the optimal size of a series of bets.

How does the Kelly Criterion work?

The formula calculates the proportion of the bankroll to wager on a given bet to maximize the logarithm of wealth.

Is the Kelly Criterion applicable to all types of trading?

While the Kelly Criterion is widely applicable, its assumptions may not hold in all market conditions. It is best used under conditions of certainty regarding win probabilities.

What happens if I miscalculate my win probability?

Miscalculating your win probability can lead to suboptimal or risky betting sizes. It is crucial to use reliable data.

Can the Kelly Criterion be used in gambling?

Yes, it is often used in gambling to maximize returns while controlling risk, but it requires accurate estimates of probabilities and payoffs.


Audit: Complete
Formula (LaTeX) + variables + units
This section shows the formulas used by the calculator engine, plus variable definitions and units.
Formula (extracted LaTeX)
\[','\]
','
Formula (extracted LaTeX)
\[f^* = \frac{bp - q}{b}\]
f^* = \frac{bp - q}{b}
Formula (extracted LaTeX)
\[f^* = \frac{(2 \times 0.6) - 0.4}{2} = 0.4\]
f^* = \frac{(2 \times 0.6) - 0.4}{2} = 0.4
Formula (extracted text)
\[ f^* = \frac{bp - q}{b} \] Where: \( f^* \) is the fraction of the current bankroll to wager; \( b \) is the odds received on the bet; \( p \) is the probability of winning the bet; \( q \) is the probability of losing the bet (1-p).
Variables and units
  • No variables provided in audit spec.
Sources (authoritative):
Changelog
Version: 0.1.0-draft
Last code update: 2026-01-19
0.1.0-draft · 2026-01-19
  • Initial audit spec draft generated from HTML extraction (review required).
  • Verify formulas match the calculator engine and convert any text-only formulas to LaTeX.
  • Confirm sources are authoritative and relevant to the calculator methodology.
Verified by Ugo Candido on 2026-01-19
Profile · LinkedIn

Kelly Criterion Calculator

Estimate the optimal bet fraction using the Kelly Criterion from win probability and win/loss ratio.

Interactive Calculator

Results

Optimal Bet Size 0%

Data Source and Methodology

All calculations are based on the standard Kelly Criterion formula as detailed in financial literature. For more information, consult authoritative sources such as academic papers and financial textbooks. All calculations strictly adhere to these sources.

The Formula Explained

\[ f^* = \frac{bp - q}{b} \]

Where:

  • \( f^* \) is the fraction of the current bankroll to wager;
  • \( b \) is the odds received on the bet;
  • \( p \) is the probability of winning the bet;
  • \( q \) is the probability of losing the bet (1-p).

Glossary of Terms

  • Win Probability (%): The estimated probability of a successful outcome.
  • Win/Loss Ratio: The ratio of the amount won to the amount lost per bet.
  • Optimal Bet Size: The calculated percentage of the bankroll to wager.

How It Works: A Step-by-Step Example

Suppose you have a win probability of 60% and a win/loss ratio of 2. Using the Kelly Criterion formula, the optimal bet size is calculated as follows:

\[ f^* = \frac{(2 \times 0.6) - 0.4}{2} = 0.4 \]

This means you should bet 40% of your bankroll.

Frequently Asked Questions (FAQ)

What is the Kelly Criterion?

The Kelly Criterion is a mathematical formula used to determine the optimal size of a series of bets.

How does the Kelly Criterion work?

The formula calculates the proportion of the bankroll to wager on a given bet to maximize the logarithm of wealth.

Is the Kelly Criterion applicable to all types of trading?

While the Kelly Criterion is widely applicable, its assumptions may not hold in all market conditions. It is best used under conditions of certainty regarding win probabilities.

What happens if I miscalculate my win probability?

Miscalculating your win probability can lead to suboptimal or risky betting sizes. It is crucial to use reliable data.

Can the Kelly Criterion be used in gambling?

Yes, it is often used in gambling to maximize returns while controlling risk, but it requires accurate estimates of probabilities and payoffs.


Audit: Complete
Formula (LaTeX) + variables + units
This section shows the formulas used by the calculator engine, plus variable definitions and units.
Formula (extracted LaTeX)
\[','\]
','
Formula (extracted LaTeX)
\[f^* = \frac{bp - q}{b}\]
f^* = \frac{bp - q}{b}
Formula (extracted LaTeX)
\[f^* = \frac{(2 \times 0.6) - 0.4}{2} = 0.4\]
f^* = \frac{(2 \times 0.6) - 0.4}{2} = 0.4
Formula (extracted text)
\[ f^* = \frac{bp - q}{b} \] Where: \( f^* \) is the fraction of the current bankroll to wager; \( b \) is the odds received on the bet; \( p \) is the probability of winning the bet; \( q \) is the probability of losing the bet (1-p).
Variables and units
  • No variables provided in audit spec.
Sources (authoritative):
Changelog
Version: 0.1.0-draft
Last code update: 2026-01-19
0.1.0-draft · 2026-01-19
  • Initial audit spec draft generated from HTML extraction (review required).
  • Verify formulas match the calculator engine and convert any text-only formulas to LaTeX.
  • Confirm sources are authoritative and relevant to the calculator methodology.
Verified by Ugo Candido on 2026-01-19
Profile · LinkedIn

Kelly Criterion Calculator

Estimate the optimal bet fraction using the Kelly Criterion from win probability and win/loss ratio.

Interactive Calculator

Results

Optimal Bet Size 0%

Data Source and Methodology

All calculations are based on the standard Kelly Criterion formula as detailed in financial literature. For more information, consult authoritative sources such as academic papers and financial textbooks. All calculations strictly adhere to these sources.

The Formula Explained

\[ f^* = \frac{bp - q}{b} \]

Where:

  • \( f^* \) is the fraction of the current bankroll to wager;
  • \( b \) is the odds received on the bet;
  • \( p \) is the probability of winning the bet;
  • \( q \) is the probability of losing the bet (1-p).

Glossary of Terms

  • Win Probability (%): The estimated probability of a successful outcome.
  • Win/Loss Ratio: The ratio of the amount won to the amount lost per bet.
  • Optimal Bet Size: The calculated percentage of the bankroll to wager.

How It Works: A Step-by-Step Example

Suppose you have a win probability of 60% and a win/loss ratio of 2. Using the Kelly Criterion formula, the optimal bet size is calculated as follows:

\[ f^* = \frac{(2 \times 0.6) - 0.4}{2} = 0.4 \]

This means you should bet 40% of your bankroll.

Frequently Asked Questions (FAQ)

What is the Kelly Criterion?

The Kelly Criterion is a mathematical formula used to determine the optimal size of a series of bets.

How does the Kelly Criterion work?

The formula calculates the proportion of the bankroll to wager on a given bet to maximize the logarithm of wealth.

Is the Kelly Criterion applicable to all types of trading?

While the Kelly Criterion is widely applicable, its assumptions may not hold in all market conditions. It is best used under conditions of certainty regarding win probabilities.

What happens if I miscalculate my win probability?

Miscalculating your win probability can lead to suboptimal or risky betting sizes. It is crucial to use reliable data.

Can the Kelly Criterion be used in gambling?

Yes, it is often used in gambling to maximize returns while controlling risk, but it requires accurate estimates of probabilities and payoffs.


Audit: Complete
Formula (LaTeX) + variables + units
This section shows the formulas used by the calculator engine, plus variable definitions and units.
Formula (extracted LaTeX)
\[','\]
','
Formula (extracted LaTeX)
\[f^* = \frac{bp - q}{b}\]
f^* = \frac{bp - q}{b}
Formula (extracted LaTeX)
\[f^* = \frac{(2 \times 0.6) - 0.4}{2} = 0.4\]
f^* = \frac{(2 \times 0.6) - 0.4}{2} = 0.4
Formula (extracted text)
\[ f^* = \frac{bp - q}{b} \] Where: \( f^* \) is the fraction of the current bankroll to wager; \( b \) is the odds received on the bet; \( p \) is the probability of winning the bet; \( q \) is the probability of losing the bet (1-p).
Variables and units
  • No variables provided in audit spec.
Sources (authoritative):
Changelog
Version: 0.1.0-draft
Last code update: 2026-01-19
0.1.0-draft · 2026-01-19
  • Initial audit spec draft generated from HTML extraction (review required).
  • Verify formulas match the calculator engine and convert any text-only formulas to LaTeX.
  • Confirm sources are authoritative and relevant to the calculator methodology.
Verified by Ugo Candido on 2026-01-19
Profile · LinkedIn
Formulas

(Formulas preserved from original page content, if present.)

Version 0.1.0-draft
Citations

Add authoritative sources relevant to this calculator (standards bodies, manuals, official docs).

Changelog
  • 0.1.0-draft — 2026-01-19: Initial draft (review required).