Keno: Probabilities, Catch Rates & House Edge Guide

You choose between 1 and 10 numbers (sometimes up to 15 or 20, depending on the game) from a pool of 80. The casino then draws 20 numbers at random. Payouts depend on how many of your numbers appear in the draw — these matches are called “catches.”

Keno is one of the oldest casino games and one of the simplest to play. There are no decisions after number selection — the outcome is entirely determined by the random draw.

The educational value of keno is exceptional because the game is a direct application of combinatorial mathematics. Every probability can be computed exactly using the hypergeometric distribution.

The number of spots you play is the most important structural decision in keno. It determines the probability distribution of catches, the payout schedule, and the volatility profile of your ticket.

Which specific numbers you pick does not matter mathematically. Every number from 1 to 80 has exactly the same probability of appearing in the draw: 20 out of 80, or 25%. The common belief that certain numbers are “hot” or “cold” is a misunderstanding of independent random events.

The draw is without replacement — once a number is drawn, it cannot appear again in the same round. This is why the math uses combinations (choosing k from n) rather than simple multiplication.

In live keno, 80 numbered balls are loaded into a bubble or hopper, and 20 are extracted. In video keno and online keno, a pseudorandom number generator selects 20 distinct numbers from the 1–80 pool.

The probability of catching exactly k numbers when you pick s spots from 80 and 20 are drawn is:

C(80, 20) — the total number of ways to choose 20 numbers from 80 — equals approximately 3.54 × 10¹⁸. This enormous denominator is why high-catch probabilities are so small: the number of favorable outcomes is a tiny fraction of total possible draws.

This is the hypergeometric distribution. Unlike a coin flip or dice roll, keno draws are without replacement, which is why simple multiplication of independent probabilities gives the wrong answer.

Video keno machines often allow 4, 10, or 20 cards simultaneously. Each card has its own set of numbers and pays independently against the same 20-number draw.

Multi-card play does not change the probability of any individual card winning. It increases total action per draw, which means the house edge applies to a larger total wager. The entertainment value is higher, but so is the per-draw cost.

Progressive keno jackpots grow with each draw until someone hits the qualifying catch (usually catching all 8, 9, or 10 on a high-spot ticket). The jackpot contribution typically comes out of the RTP, meaning the base paytable is even worse than standard keno.

In theory, a progressive jackpot could grow large enough that the expected value of the ticket becomes less negative. In practice, this almost never happens because the qualifying catch is so rare and the jackpot is usually hit before reaching that threshold.