Casino House Edge Explained: The Math Behind Every Bet

How the chandelier gets paid for

Walk into a bright casino. See the big lights, soft seats, and the tall glass bar. Nothing here is an accident. Every chair, every bell, every carpet line is paid for by a tiny slice of each bet. That small slice has a name: house edge. It is not a trick or a scam. It is math. And it is baked into almost every game on the floor.

This guide shows what house edge is, how it is set, and how rules and skill change it. We will do quick math checks you can follow. We will show a clear table of common bets. We will point you to trusted sources. And we will keep the language plain and direct.

Quick answer first: the one-sentence truth

House edge is the average rate the casino expects to win on a bet, set by the game’s rules, over many plays. For a clear house edge definition, think of it as the built‑in fee you pay to play, shown as a percent of your stake.

The truth-in-numbers table (what you play is what you pay)

Use this table to see typical house edges and what can move them. Local laws and table rules can shift numbers a lot. Slots and video poker pay tables also change by place and time. For real data across years, check state reports, like Nevada’s public charts on casino hold and player payback data.

Roulette (Single-Zero)	Even-money (outside)	~1.35% (with en prison / la partage), ~2.70% (standard)	None	Low–Med	Special rules on even-money bets cut edge in half
Roulette (Double-Zero)	Even-money (outside)	~5.26%	None	Low–Med	Extra 00 adds edge; avoid if single-zero is offered
Roulette (Single-Zero)	Straight-up (1 number)	~2.70%	None	High	Big swings; same edge as other inside bets (no en prison)
Blackjack	3:2 payouts, S17, DAS, basic strategy	~0.30%–0.50%	High	Med	6:5 or H17 raise edge fast; rules matter a lot
Blackjack	6:5 payouts, H17, no surrender	~1.5%–2.0%+	High	Med	Looks small, costs big over time
Baccarat	Banker bet (5% commission)	~1.06%	None	Low	Best common bet on many floors
Baccarat	Player bet	~1.24%	None	Low	Close to Banker, but a bit worse
Baccarat	Tie bet	~14%+	None	High	Pays a lot, costs a lot
Craps	Pass Line (no odds)	~1.41%	Low	Med	Good base bet
Craps	Pass Line + Max Odds	~1.41% on line; 0% on odds	Low	Med–High	More odds = lower blended edge on total stake
Video Poker	Jacks or Better 9/6, optimal play	~0.46%	High	Med	Pay table is key; skill matters
Video Poker	Poor pay tables (e.g., 8/5)	~2%–3%+	High	Med	Same game name, worse math
Slots	$0.01–$1 denom (common)	~4%–12% (varies by venue)	None	High	RTP is set by chip/profile; often not shown
Keno	Straight ticket	~20%–35%	None	High	Among the worst edges on the floor
Big Six Wheel	Any number	~11%–24%	None	High	Simple, but very costly on average

All values are typical and may vary by rules, pay tables, or local law. Ask for rule cards or pay table screens and compare before you play.

Two-minute math check: EV without the headache

You do not need a math degree to see why the house wins. One idea is enough: expected value (EV). EV tells you the average change to your stake for one bet if you could run it a huge number of times. A simple form is: EV = sum of (probability × payoff) − stake. If EV is negative, the game takes a slice on average. For a friendly walk‑through on this idea, see expected value explained.

Roulette is a clean test. On a single‑zero wheel, there are 37 pockets: 18 red, 18 black, and one zero. If you bet $1 on red (even‑money), your chance to win is 18/37 and to lose is 19/37. EV = (18/37 × +$1) + (19/37 × −$1) = −$1/37 ≈ −2.70%. That is the house edge for that bet. Over a long run, you lose about 2.7 cents per dollar bet.

Switch to a double‑zero wheel (38 pockets). Now the math is worse. EV on even‑money = (18/38 × +$1) + (20/38 × −$1) = −$2/38 ≈ −5.26%. That small extra zero doubles the long‑term cost on many bets. This is why table rules and wheel type matter. For a deeper but clear view of the math, see probability and expected value.

Skill, rules, and the “you control some of it” factor

Blackjack is the big case where player choices matter. With good rules (3:2 for blackjack, dealer stands on soft 17, double after split, surrender allowed) and basic strategy, the house edge can drop under 0.5%. Change one line on the felt (say, 6:5 for blackjack or dealer hits soft 17), and the edge jumps. A rule card or felt print defines the math. For a broad set of studies and charts, the UNLV team keeps deep notes on blackjack rules and house edge by rule set.

Video poker looks like slots, but it runs on stated pay tables. A classic “9/6 Jacks or Better” (9 for full house, 6 for flush) with perfect play is close to 99.54% return. Shift that to “8/5,” and the edge leaps. Skill is key, and so are the pay tables on the screen. For source work and archives, see video poker paytables research held by UNLV libraries and gaming collections.

Craps gives you a rare bet with no house edge: the free odds you take behind a Pass or Don’t Pass. The line bet still has an edge, but odds bets pay at true odds. The more odds the table allows, the lower your blended edge on the total money you put at risk. To step back and see the full layout and its many bets, read a neutral craps odds and house rules overview.

Baccarat is simple by design. The Banker bet is best at about 1.06% edge, thanks to a 5% fee on wins. The Player bet is close at ~1.24%. The Tie bet pays more but comes with a huge edge (often over 14%). If you wonder why the fee exists at all, start here: baccarat banker commission rationale.

Slots and the stuff you don’t see (PAR sheets, RNG, volatility)

Slots hide their math more than table games. Each title has a pay table on the glass, but the true return is set in a profile on the chip. Makers create a few return options for each game. The casino picks one when they install it. Public rules in some places ask for ranges, but most floors do not show the exact RTP by unit. The U.K. has clear notes on what “return to player” means in law; see RTP guidance for remote games.

What about fairness? Slots use a random number generator (RNG) to map spins to results. Labs test and seal games so the math matches the approved profile and the RNG passes checks. That does not raise the RTP, but it keeps the game honest to its file. If you want to know who does that work, look at gaming device certification groups like GLI.

Volatility is the feel of a game. High‑volatility slots pay less often but hit bigger when they do. Low‑volatility slots pay more often but in small drops. Both can have the same RTP. That is why two games can feel so different in one hour even if both return 96% in the long run. Short runs swing. Long runs level out.

Also note: denomination matters. Often, higher‑denom slots have better returns than penny machines on the same floor. That is not a law, but it shows up in state reports. It pays to check.

Sports betting math in one line (-110 and beyond)

On most point spreads, you lay -110. Risk $110 to win $100. If the true game is 50/50, the book’s fee (the “vig”) is built in. EV = 0.5 × $100 − 0.5 × $110 = −$5 per $110 risked, or about −4.54%. That is the house edge for an even game at -110. Change the price to -105 and the edge drops; move to -115 and it rises. Parlay cards pack more edge because each leg multiplies both the risk and the fee. For a broad look at how books make money and where the fees sit, browse the AGA hub on sports betting economics.

Variance is not the villain (short term vs long term)

Variance is why a bad bet can win today and a good bet can lose now. It is the bounce in your results. High‑variance games like slots and straight‑up roulette can jump a lot in one session. Low‑variance games like baccarat banker feel smoother, but swings still happen. Variance does not change the house edge. It only changes how fast or slow you feel the pull of it.

Over many plays, the average result moves toward the math. This is the law of large numbers. It does not mean you “must” win after a loss streak. It means the average result will tend to the EV as the count of trials grows. If you want a clear class note on this idea, see MIT’s page on the law of large numbers.

Practical picks: what to play, what to skip (not advice, just math)

• Better picks, if you want lower long‑term cost: Single‑zero roulette over double‑zero. If you can find en prison or la partage on even‑money bets, that is even better. Baccarat banker. Simple, steady, low edge. Player is close too. Blackjack with 3:2 payouts, S17, DAS, surrender. Use basic strategy. Avoid 6:5. Video poker with strong pay tables (e.g., 9/6 Jacks or Better) and optimal play. Craps Pass (or Don’t Pass) plus max odds allowed.
• Single‑zero roulette over double‑zero. If you can find en prison or la partage on even‑money bets, that is even better.
• Baccarat banker. Simple, steady, low edge. Player is close too.
• Blackjack with 3:2 payouts, S17, DAS, surrender. Use basic strategy. Avoid 6:5.
• Video poker with strong pay tables (e.g., 9/6 Jacks or Better) and optimal play.
• Craps Pass (or Don’t Pass) plus max odds allowed.
• Poor picks, if you care about edge: Keno and Big Six wheel. Fun and simple, but very high edge. Double‑zero roulette when single‑zero is also on the floor. Blackjack with 6:5 payouts or other harsh rules.
• Keno and Big Six wheel. Fun and simple, but very high edge.
• Double‑zero roulette when single‑zero is also on the floor.
• Blackjack with 6:5 payouts or other harsh rules.
• Comps and promos: They can cut your “effective edge” a bit. A 0.2%–0.5% comp rate on coin‑in helps, but it does not flip a bad game into a good one. Take the value, but do not chase it.
• Rules move. Before you sit down, read the felt or pay table. Ask the dealer. Compare across rooms.

• Single‑zero roulette over double‑zero. If you can find en prison or la partage on even‑money bets, that is even better.
• Baccarat banker. Simple, steady, low edge. Player is close too.
• Blackjack with 3:2 payouts, S17, DAS, surrender. Use basic strategy. Avoid 6:5.
• Video poker with strong pay tables (e.g., 9/6 Jacks or Better) and optimal play.
• Craps Pass (or Don’t Pass) plus max odds allowed.

• Keno and Big Six wheel. Fun and simple, but very high edge.
• Double‑zero roulette when single‑zero is also on the floor.
• Blackjack with 6:5 payouts or other harsh rules.

Your bench of sources (and where to dig deeper)

Data beats hype. Regulators post hold and payout reports. Universities keep archives of rule sets and pay tables. Stats classes explain the core math. That mix will serve you better than ads and splash screens. If you want a map for a new room, start with reports, then look at the felt, then play small while you confirm how a table runs.

If you want a quick way to compare real table rules or see current pay tables before you play, I keep a neutral notes page with field checks and screenshots. For readers in Sweden who compare welcome offers and BankID flow, I also keep a plain‑language field report at casino med free spins that links rules and on‑site photos so you can verify terms before you sit down.

Mini‑FAQ

Is house edge the same as RTP?

They point to the same idea from two sides. House edge is the share the casino keeps on average. RTP (return to player) is what comes back to players on average. If RTP is 97.3%, the house edge is 2.7%.

Can strategy beat the house long‑term?

In most games, no. In blackjack, strong skill and rare, clean rules can get you close to break even before comps. Advantage play (like card counting) is real but hard, and casinos watch for it. In video poker, perfect play on top pay tables can be near even. Most players do not reach that level.

Why do some slots feel “hot”?

Short‑term luck and high variance. The RNG does not remember. Past spins do not change future spins. A hot streak is just a streak. It can end at any time.

What is the lowest house edge I can find?

Baccarat banker is one of the best common bets (~1.06%). Blackjack can get near or below 0.5% with great rules and perfect basic play. Craps odds bets have 0% edge, but you must place a line bet first, which has an edge.

Does table speed change house edge?

No. It changes how fast you face it. More hands per hour mean more exposure to the same edge. Slower play lowers loss per hour, on average.

Small myths to drop right now

• “I am due.” No. Trials are independent. The wheel and the shoe do not track your pain.
• “Higher payback means easy wins.” No. RTP is a long‑run stat. Variance can hide it for hours.
• “Comps make the math fair.” No. They help, but they do not erase the edge.
• “Dealer skill matters in roulette.” No. The wheel and ball set the odds. One zero or two is what counts.

Hands‑on mini checks you can use at the table

• Roulette wheel check: Count the zeros. One zero good. Two zeros bad. En prison or la partage on even‑money is a clear plus.
• Blackjack felt scan: Look for “Blackjack pays 3:2,” “Dealer stands on soft 17,” “Double after split,” “Surrender.” Any 6:5 sign is a red flag.
• Video poker screen: Tap “Help/Paytable.” If Jacks or Better does not show “9/6,” know you pay more to play.
• Craps odds: Ask max odds. If the sign says 3x‑4x‑5x or higher, good. Take them if your bankroll can swing.
• Slots denomination: If you can, move up a denom one step. Many floors set higher returns there.

Responsible play and closing note

Set a budget you can afford to lose. Set a time limit. Take breaks. Never chase. If you feel stress or loss of control, stop and get help. In the U.S., start with the National Council on Problem Gambling’s problem gambling help page. In other regions, check local health sites or helplines.

House edge is not a moral call. It is a math fact. If you choose to play, know the numbers, pick the better rules, and enjoy the night for what it is: paid entertainment with swings.

Sources and methodology

Numbers in this guide come from a mix of regulator reports, standard math texts, and long‑run tests on pay tables. For fast checks, see Nevada’s payout reports, the UKGC’s RTP guidance, and GLI’s notes on device tests. For math basics, see the EV and LLN links above. This page is for education, not for tips or sure wins.

• Definitions: Investopedia on house edge.
• Math: Khan Academy (EV), Wolfram (expected value), MIT OCW (law of large numbers).
• Games: UNLV Center for Gaming Research; UNLV Libraries gaming collections.
• Rules and odds: Britannica (craps, baccarat).
• Devices and fairness: GLI certification notes.
• Market view: AGA resources on sports betting.
• Public returns: Nevada Gaming Control Board reports.

About the author: I study casino math and track rule sheets and pay tables in the field. I test examples by hand and with simple code. I update this page when rules change or when new public data is posted. Last reviewed: this year.