How does Kelly Criterion work for tournaments?

Kelly Criterion for tournaments adapts the original formula to account for discrete, heavily right-skewed payout distributions. Instead of a simple edge/odds calculation, tournament Kelly incorporates your ROI, field size, and the actual payout structure to determine what fraction of your bankroll each buy-in should represent.

What buy-in should I play with my bankroll?

Use the Half-Kelly recommendation: divide your bankroll by the calculator's suggested number of buy-ins. For example, with a $10,000 bankroll and 30% ROI in 1,000-player fields, Half-Kelly typically recommends buy-ins representing 0.5-1.5% of your bankroll. The exact amount depends on field size and your edge.

Why is Half-Kelly better for MTTs?

Full Kelly maximizes long-run growth rate but assumes you know your exact edge and face continuous bet sizing. Tournament poker violates both assumptions: ROI estimates are noisy, and buy-ins are discrete. Half-Kelly sacrifices roughly 25% of the theoretical growth rate while cutting variance by 50% and dramatically reducing the probability of large drawdowns.

How does field size affect Kelly recommendations?

Larger fields increase variance per tournament because payouts become more top-heavy and min-cash frequency decreases. Kelly responds by recommending smaller buy-ins relative to bankroll. A player with 30% ROI should use roughly 40% smaller buy-ins in a 5,000-player field compared to a 200-player field.

MTT Kelly Calculator

Optimal tournament buy-in for your bankroll under Kelly Criterion.

Kelly Parameters

Your ROI (%)

Average Field Size

Typical Buy-in ($)

Current Bankroll ($)

Calculating Kelly allocation...

Half-Kelly max buy-in	--
Bankroll in buy-ins	--
EV per tournament	--

Buy-in Levels

Buy-in	Kelly Utilization	Recommendation

Growth Rate Comparison

Strategy	Buy-in	Growth Rate	Drawdown Risk

What the Numbers Mean

The half-Kelly max buy-in is the largest tournament you should regularly fire given your bankroll, ROI, and typical field size. Unlike a simple bankroll-divided-by-X rule, this calculator models actual payout distributions for the field size you enter. A 1,000-player field pays out differently than a 200-player sit-and-go, and the Kelly fraction adjusts accordingly. If the number is below your usual buy-in, your bankroll does not support your current schedule at half-Kelly sizing. If it is well above, you have room to take shots at higher stakes or add volume at your current level.

Field Size and Variance

Larger fields produce more top-heavy payout structures. In a 200-player tournament, the top prize might be 25-30% of the pool. In a 5,000-player field, first place can exceed 15% of a much larger pool, but the probability of getting there drops proportionally. Kelly responds to this by recommending smaller buy-ins relative to bankroll as field size grows. A player with 30% ROI should use roughly 40% smaller buy-ins in a 5,000-player field compared to a 200-player field. Different rooms run different field sizes at similar buy-in levels, so the room you play on directly affects your Kelly allocation even if buy-in and ROI stay the same.

What This Calculator Does Not Do

ROI is assumed constant across all buy-in levels and field sizes. In practice, your edge may differ at different stakes. The model does not account for late registration, re-entry effects on payout structure, or satellite entries that change your effective buy-in. For a full Monte Carlo simulation of your tournament bankroll trajectory, use the MTT bankroll simulator.