What “house edge” means (and the quick math)
House edge is the casino’s average profit on a bet, measured as a percentage of your initial wager. If a game has a 5% house edge, the long-run average loss is $5 for every $100 bet. Mathematically it’s the expected loss divided by the initial bet; this is the standard definition used by casino-math references.
A useful cousin is “element of risk”: expected loss divided by the total amount you put at risk when a game allows raises (e.g., doubling in blackjack). It’s the better way to compare games that have extra wagering after the first bet.
House edge vs. RTP vs. volatility
Return to Player (RTP) is the long-run percentage a game pays back. It complements house edge (RTP + house edge ≈ 100%). Regulators explain RTP for gaming machines and why it’s measured over very many plays; your short-term results still swing around the average. Volatility describes swing size and frequency, not the edge.
Why the house wins in the long run (not on every spin)
Over many trials the law of large numbers makes actual results converge toward a game’s mathematical expectation—i.e., the house edge shows up more reliably the longer you play. That doesn’t mean past spins “owe” you a win; believing they do is the gambler’s fallacy.
Typical house edges (2025 snapshot)
| Game / Rule | House Edge |
|---|---|
| Roulette – American (0,00) | 5.26% |
| Roulette – European (single zero) | 2.70% |
| Roulette – Triple zero | 7.69% |
| Roulette – European with La Partage/En Prison (even-money bets) | ~1.35% |
| Blackjack (baseline rules, basic strategy) | ~0.5–0.7% (varies by rules) |
| Blackjack with 6:5 natural payout (vs 3:2) | adds ~1.39% to the edge |
| Craps – Pass Line | 1.41% |
| Craps – Free Odds (behind Pass/Don’t) | 0.00% on the odds portion |
| Baccarat – Banker / Player / Tie | 1.06% / 1.24% / ~14% |
| Video Poker – 9/6 Jacks or Better (perfect play) | 99.54% RTP (0.46% edge) |
Sources and notes: roulette edges, including the 5-number bet and triple-zero; La Partage halves the edge on even-money bets; blackjack rule impacts (6:5 vs 3:2); craps Pass Line and zero-edge odds; baccarat edges; video poker 9/6 JoB return.
How small rule changes swing the edge
Blackjack: the 6:5 trap
Paying 6:5 on a natural instead of 3:2 increases the house edge by about 1.39%—a huge jump for a single rule. If a 3:2 table is ~0.5–0.7%, a 6:5 table can push you well above 1.8% depending on other rules. Always prefer 3:2.
Roulette: zeros and protective rules
American wheels add a second zero that pushes the edge to 5.26%; triple-zero jumps to 7.69%. Conversely, La Partage or En Prison on European wheels return half or delay even-money losses on a zero, cutting those bets’ edge to ~1.35%.
Craps: use free odds
The Pass Line is 1.41%, but the free Odds bet behind it has no house edge (true odds payouts). That reduces your overall cost per unit of total money at risk—even though the original Pass Line itself stays 1.41%.
Slots and video poker: paytables matter
On slots, RTP is set in the math and can vary widely by title and jurisdiction; check the game info or the casino’s help pages where available, and remember the variance can be high. Regulators’ RTP materials explain what those percentages mean over time. On video poker, a small paytable tweak dramatically shifts return (e.g., 9/6 vs 9/5 Jacks or Better).
Fair games can still favor the house
Independent labs test game math and random number generators (RNGs) against technical standards such as GLI-11; that’s about randomness and rules compliance, not giving the player an advantage. A game can be perfectly fair and still have a built-in edge via its payouts.
Hold vs. house edge: a quick distinction
Industry reports often publish win % / hold %—the share of player handle the casino kept over a period. That’s a historical accounting measure and can differ from a game’s theoretical house edge, which is the long-run expectation built into the rules.
Your expected loss per hour (and an example)
A handy estimate:
expected loss ≈ average bet × decisions per hour × house edge.
Example: $10 average bet at American roulette, ~50 spins/hour. Total wagered = $10 × 50 = $500. At 5.26%, expected loss ≈ $500 × 0.0526 = $26.30 per hour. (Your real results will vary because of variance.) Numbers for the edge from the roulette references above.
Simple ways to lower the edge you face
- Prefer European roulette, and even better if the table offers La Partage/En Prison; avoid triple-zero.
- In blackjack, always choose 3:2 games, and learn basic strategy; avoid 6:5 or penalty rules.
- In craps, make Pass/Don’t and put the maximum free odds you can afford; skip high-edge prop bets.
- On baccarat, stick to Banker or Player; skip Tie and most side bets.
- For video poker, hunt for full-pay machines and play correct strategy (e.g., 9/6 JoB at 99.54% RTP).
FAQs
Is the house edge a guarantee I’ll lose?
No. It’s a long-run average. Short-term results can be positive or negative; the law of large numbers explains the convergence only over many trials.
If a number hasn’t hit in roulette, is it “due”?
No—spins are (ideally) independent. Believing past results change future probabilities is the gambler’s fallacy.
Do comps change the edge?
Comps don’t change the math of the game, but they effectively rebate a small portion of expected loss (casinos often comp a fraction of the theoretical). Still, playing lower-edge rules saves far more than comps return.
