What Is Theo? The Formula Casinos Use to Decide What You're Worth

Theo, short for theoretical loss, is the number a casino expects to win from your play over time. It is not what you actually lost. It is what the math says your action was worth, and nearly every comp decision (free play, meals, rooms, host attention) runs through it.

The formula

Casinos calculate theo the same basic way everywhere:

Theo = average bet × decisions per hour × hours played × house edge

A concrete example: you play blackjack at $25 a hand, the table deals about 70 hands per hour, you play 4 hours, and the casino rates the game at a 1.5% edge against the average player.

$25 × 70 × 4 × 1.5% = $105 of theo

You might have walked away a winner that day. The casino does not care. Your rating for the trip is $105, because that is what your action is worth to them on average, replayed thousands of times.

Why actual losses barely matter

New players often assume a big losing day earns big comps. It usually does not, and the reverse is also true: a winning player with heavy action still earns strong comps. Casinos comp the volume and quality of your play, not the outcome, because outcomes are noise and theo is signal. Some properties do track actual loss and blend it into host decisions, but the rated backbone is theo.

What percentage of theo comes back to you?

The standard industry range is roughly 10% to 40% of theo returned as comps, depending on the property, your tier, and how badly they want your segment of play. Using the example above, a $105 theo day might earn $10 to $40 in comp value. That is why comps can never make a negative expectation game profitable: you are getting back a slice of what the math already took.

How the inputs get fudged

Every input in the formula is an estimate, and the estimates favor the house:

• Average bet comes from periodic floor checks at table games. Bet big when the pit looks over and small when they do not, and your rating drifts up. Slots need no estimate at all: the card tracks every cent of coin-in exactly.
• Decisions per hour is a house assumption. A full blackjack table deals far fewer hands per player than a heads-up game, which is one reason identical bettors get different ratings.
• House edge is rated against an average player, not an optimal one. A perfect basic strategy player gets rated at the same edge as the tourist hitting hard 17.

That last point cuts both ways. Skilled play lowers your real cost below your rated theo, which makes low-edge games played well the best comp deal in the building.

The takeaway

Know your theo before you value a comp. If a “free” room required $400 of theo to earn, the room was not free. Run your own numbers with the comp calculator and compare what you gave to what you got.

Educational explanation only. No real-money gambling happens on LearnTheOdds.

Play for entertainment, not income. The math favors the house over time. Set limits, never chase losses, and if it stops being fun, take a break. 21+. Need help? Call 1-800-MY-RESET (1800myreset.org).