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Poker glossary

Variance

What it means

Variance measures how much your actual results differ from your expected results over a given period. It’s the mathematical reality that even when you make correct decisions, you can still lose money in the short term - or win more than you should. High variance means bigger swings up and down; low variance means results closer to expectation.

How it works at the table

Say you’re playing $1/$2 and get dealt AA five times in a session. The expected value says you should win about 85% of these hands against a single opponent. But variance means you might win all five (lucky) or lose three of them (unlucky). One player shoves 100bb with K♦K♠, you call with A♠A♦, and the board runs out K♥ 7♣ 2♦ 8♠ 3♥. You played perfectly but lost $200. That’s variance. Over thousands of hands, these swings balance out, but any single session can deviate wildly from expectation.

Strategic context

Understanding variance helps you make better decisions about bankroll management and game selection. Tournament players face higher variance than cash game players because of the top-heavy payout structures. Playing loose-aggressive creates more variance than tight play. You need a bigger bankroll to handle the swings if you’re playing high-variance styles or formats. Professional players think in terms of expected value, not results, because they know variance evens out over time.

Common mistakes

Players often confuse variance with bad play - losing three buy-ins doesn’t mean you’re playing poorly. They also change their strategy after a downswing, tightening up unnecessarily or making desperate moves to “get even.” Another error is playing stakes too high for their bankroll, where normal variance can wipe them out. Many players claim “bad variance” when they’re actually making -EV decisions.

Variance connects directly to implied odds since high-variance plays often rely on hitting big hands occasionally. Standard deviation measures variance mathematically - most poker results fall within two standard deviations of expectation. The concept of equity helps you understand your expected value, while variance explains why actual results differ. Risk of ruin calculations use variance to determine safe bankroll requirements for different games and stakes.