Kelly Criterion Calculator

How much of my bankroll should I stake on a bet I believe has an edge?

The whole amount you are betting with, not the balance in front of you today.
The price you can actually get. Use the odds converter if the book quotes fractions or American prices.
Yours, and the only input here that is not a fact. Kelly amplifies an over-estimate faster than it rewards a correct one.
Full Kelly is the growth-optimal stake and is far more volatile than most people expect. Fractional Kelly gives up a little growth for a much smoother ride.
Stake this bet deserves41.82

The arithmetic,
line by line.

Every step of the Kelly Criterion Calculator, for the figures currently entered
StepValue
What one unit wins — decimal odds − 11.1000
Expected value per unit staked at 52.00%0.0920
Kelly fraction f*8.36%
Applied at half Kelly4.18%
Stake41.82
b  = decimal odds − 1        (what one unit wins)
p  = your probability ÷ 100
q  = 1 − p
f* = (b × p − q) ÷ b         (Kelly, 1956)
stake = bankroll × f* × fraction, and 0 whenever f* ≤ 0

Kelly Criterion Calculator by Solaspins