Kelly Criterion Calculator

Even if you have spotted a value bet, the main question remains: how much should you stake? Stake too much and you can quickly burn through your bankroll; stake too little and you miss out on profit. A Kelly Criterion Calculator solves that problem by telling you the optimal stake size, balancing risk and expected return.

What is the Kelly Criterion?

The Kelly Criterion is a formula that shows what fraction of your bankroll you should wager to achieve the maximum long-term growth of capital.

It factors in both the bookmaker’s odds and your own probability estimate. When your assessed probability is higher than the probability implied by the odds, Kelly computes the stake size that is both profitable and safe.

How the Kelly Calculator Works

To run a calculation, you enter:

• The bookmaker’s odds for the chosen outcome;
• Your true probability estimate (e.g., 60 %);
• Your current bankroll, from which the stake will be calculated.

Using the Kelly formula, the calculator tells you what share of your roll to stake for the best long-term result.

EXAMPLE

You believe the true probability is 60 %, while the bookmaker offers odds of 2.00. Your bankroll is $1,000.

The Kelly Calculator shows that the optimal stake is 10 % of your roll, or $100—a safe, mathematically sound choice.

How to Use the Kelly Calculator — Step by Step

1. Estimate the probability. Analyse the event and decide the chance of the desired outcome.
2. Check the odds. Find the price in the bookmaker’s line.
3. Enter your bankroll. This is your overall betting budget.
4. Plug the data into the calculator. Input odds, probability, and bankroll size.
5. Read the result. The tool shows what percentage of the roll you should stake.

Points to Remember:

• Kelly offers no guarantee on any single bet; its edge appears over a large sample of wagers.
• Over-estimating probability will inflate the recommended stake—stay objective.
• Many bettors use a fractional Kelly (e.g., half-Kelly) to reduce variance, staking only part of the calculated amount.

A Kelly Calculator is an excellent assistant for anyone who wants to bet rationally and manage their bankroll with discipline.