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What is Variance in Poker? A Plain-English Guide

·8 min read

Understand variance, standard deviation, and downswings — and why a winning player can lose for months. With concrete numbers for NL cash and MTTs.

Variance is the reason poker is profitable. It's also the reason most people quit. Understanding it is the difference between a career and a hobby that ends in frustration.

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The one-sentence definition

Variance is how far your real results swing around your true win rate. High variance = bigger swings in both directions, even though your long-term EV is unchanged.

Concrete numbers

For a winning NL100 online cash player with a true win rate of 5 bb/100 and standard deviation of 100 bb/100:

  • 10,000 hands: there is a ~16% chance you're losing. Sixteen percent. After ten thousand hands.
  • 100,000 hands: still ~6% chance of being a loser despite being a real winner.
  • 1,000,000 hands: finally below 1%.

For MTTs, a player with 20% ROI can lose money over 40,000 tournaments. Most live grinders won't play that many in a decade.

What this means in practice

  • A 3-month downswing tells you almost nothing about your skill.
  • A 2-week heater tells you even less.
  • Sample size is the only honest answer to "am I actually good?"

How to survive variance

  1. Bankroll — see our bankroll guide. The numbers are not arbitrary; they're calibrated to typical SD.
  2. Track everything — without a database of sessions, you can't separate a downswing from a leak.
  3. Review hands, not results — if you'd play the hand the same way again with full information, the result is irrelevant.
  4. Don't move down emotionally, move down by rule — pre-commit: "If I drop X buy-ins from peak, I move down a stake."

The mindset shift

Stop asking "did I win?" after a session. Start asking "did I make good decisions?" The first question has a 50/50 answer driven by noise. The second is the only one you can control — and the only one that compounds.

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