Kelly Criterion betting calculator

The Kelly Citerion calculator calculates:

• The optimal stake according to the Kelly Criterion

Calculating the optimal stake according to the Kelly criterion
The Kelly criterion calculates your optimal stake based on the size of your bank relative to the difference between a selection's price and its actual probability of winning (ie relative to the "value" in the price). In this example, you have a bank of £250 and want to back a selection priced at 2.22 because you believe that it has a 50% chance of winning. The Kelly Criterion calculator recommends an optimal stake of £22.54.


Note that if the selection were priced at 2.00, the Kelly criterion would recommend a stake of £0.00, in other words "no bet". Another way of looking at this is to consider that the rational better would decline the offer of evens for heads in a coin toss. If you are using a betting exchange price, also remember to use Actual Pricer to obtain the selection's effective price after commission.