--- title: "Why the house edge decides every long game" url: https://get-certified.net/ description: "How games of chance actually work: odds and expected value, the house edge derived from payout terms, game design, the history of lotteries and betting, and how." --- # Why the house edge decides every long game Mathematics · Updated 17 August 2026 The advantage a gambling game holds is not luck, a streak or a mood. It is a fixed fraction of every stake, written into the payout terms before anyone plays. Expected bankroll against number of bets. The line is straight because each bet subtracts the same fraction of the amount staked. [Read the full guide on the house edge](https://get-certified.net/house-edge/) ## Field notes [01**Best Casino Slots: Buffalo Gold, Dragon Link and Others**Sep 16, 2026](https://get-certified.net/best-slot-machines-to-play-at-the-casino-a-safer-selection-guide/) [02**How Betting Bankroll Limits Work: A Practical Checklist**Sep 14, 2026](https://get-certified.net/how-betting-bankroll-limits-work-a-practical-checklist/) [03**The 10 Best Sweepstakes Casinos for Slots Variety**Aug 23, 2026](https://get-certified.net/the-10-best-sweepstakes-casinos-for-slots-variety/) [04**Free Play: What to Look for in a Sweepstakes Casino**Aug 15, 2026](https://get-certified.net/free-play-what-to-look-for-in-a-sweepstakes-casino/) [05**Top 7 Alternatives of Playtech**Aug 15, 2026](https://get-certified.net/top-7-alternatives-of-playtech/) [06**Payment Collection: A Practical Guide for Enterprise Operations**Aug 12, 2026](https://get-certified.net/payment-collection-a-practical-guide-for-enterprise-operations/) [07**Welcome Bonuses: What to Look for in a Sweepstakes Casino**Aug 09, 2026](https://get-certified.net/welcome-bonuses-what-to-look-for-in-a-sweepstakes-casino/) [08**How to Choose the Best Sweepstakes Casinos for Instant Withdrawals**Aug 08, 2026](https://get-certified.net/how-to-choose-the-best-sweepstakes-casinos-for-instant-withdrawals/) [09**Top 5 Sweepstakes Casinos for Legit Payouts**Aug 06, 2026](https://get-certified.net/top-5-sweepstakes-casinos-for-legit-payouts/) [10**The 10 Best Sweepstakes & Social Casinos for Sweepstakes Eligibility**Aug 02, 2026](https://get-certified.net/the-10-best-sweepstakes-social-casinos-for-sweepstakes-eligibility/) More [11**Who's the Best for Game Aggregation Services: SOFTSWISS vs Kanggiten**Jul 30, 2026](https://get-certified.net/who-s-the-best-for-game-aggregation-services-softswiss-vs-kanggiten/) [12**Sweeps Coins Value: What to Look for in a Sweepstakes Casino**Jul 28, 2026](https://get-certified.net/sweeps-coins-value-what-to-look-for-in-a-sweepstakes-casino/) [13**6 WhatsApp Bulk Message Sender Tools for Customer Updates**Jul 26, 2026](https://get-certified.net/6-whatsapp-bulk-message-sender-tools-for-customer-updates/) [14**Top 3 Alternatives of NuxGame for Turnkey Solutions**Jul 23, 2026](https://get-certified.net/top-3-alternatives-of-nuxgame-for-turnkey-solutions/) [15**Top 7 Alternatives of Tecpinion**Jul 23, 2026](https://get-certified.net/top-7-alternatives-of-tecpinion/) [16**Who's the Best for Live Casino Studios: Playtech vs Kanggiten**Jul 22, 2026](https://get-certified.net/who-s-the-best-for-live-casino-studios-playtech-vs-kanggiten/) Key result edge = 1/37 = 2.70% single-zero roulette: 35 to 1 on 1 of 37 pockets -> return 36/37 = 0.9730 -> edge 0.0270 ## All guides, most recently revised first 1. Mathematics · Updated 17 August 2026[Why the house edge decides every long game](https://get-certified.net/house-edge/)A fixed fraction of every stake, set by paying less than true odds. 2. Mathematics · Updated 17 August 2026[Probability, odds and expected value](https://get-certified.net/probability-and-odds/)Fractional, decimal and implied probability, and how expectation is computed. 3. Games · Updated 17 August 2026[Roulette: a fixed edge built into the wheel](https://get-certified.net/roulette/)One or two extra pockets set an edge that every bet on the cloth shares. 4. Games · Updated 17 August 2026[Dice: the oldest randomiser](https://get-certified.net/dice-games/)The thirty-six outcomes of two dice, and the pass line derived from them. 5. Games · Updated 17 August 2026[Cards: where skill changes the arithmetic](https://get-certified.net/card-games/)Dependent draws, combinatorics of 52 cards and the limits of skill. 6. Games · Updated 17 August 2026[Slot machines: from reels to number generators](https://get-certified.net/slot-machines/)Weighted stops, virtual reels and what a return figure actually means. 7. Games · Updated 17 August 2026[Lotteries: the arithmetic of very long odds](https://get-certified.net/lotteries/)Combinations, prize-fund share, rollovers and shared jackpots. 8. Games · Updated 17 August 2026[Betting markets, prices and the overround](https://get-certified.net/betting-markets/)Converting prices to probabilities and reading the margin in a book. 9. History · Updated 17 August 2026[A short history of games of chance](https://get-certified.net/history-of-games-of-chance/)Astragali to cards to the seventeenth-century correspondence that started probability. 10. Design · Updated 17 August 2026[How games of chance are designed](https://get-certified.net/how-games-are-designed/)Paytables set below true odds, hit frequency and the volatility trade-off. 11. Regulation · Updated 17 August 2026[How regulation of the industry developed](https://get-certified.net/regulation/)From prohibition to licensing, testing regimes and published return figures. 12. Glossary · Updated 17 August 2026[Glossary of terms](https://get-certified.net/glossary/)Twenty-four defined terms with links into the guide that develops each. 13. Method · Updated 17 August 2026[How these guides are written](https://get-certified.net/method/)Scope, derivation, and what this site deliberately does not do. ## Seven common bets, and what each keeps Each row is derived from the payout terms alone. The last column shows the arithmetic. *Expected return and house edge derived from payout terms* | Bet | Payout terms | Expected return | House edge | Arithmetic | |---|---|---|---|---| | Single-zero roulette, straight | 35 to 1, 1 of 37 | 0.9730 | 2.70% | 36/37 | | Double-zero roulette, straight | 35 to 1, 1 of 38 | 0.9474 | 5.26% | 36/38 | | Coin toss at evens | 1 to 1, 1 of 2 | 1.0000 | 0.00% | 2 x 1/2 | | Craps pass line | 1 to 1, p = 244/495 | 0.9859 | 1.41% | 2 x 244/495 | | Lottery, 6 from 49 jackpot | share of prize fund | set by fund share | large | 1 in 13,983,816 | | Two-way market at 10/11 each | 10 to 11 both sides | 0.9545 | 4.55% | 1/1.0476 | | Machine stating 96% return | declared paytable | 0.9600 | 4.00% | 1 - 0.96 | ## How these guides are worked out Every figure on this site is derived from the stated rules of the game it describes, using elementary probability, and the arithmetic is printed beside the result so that a reader can check it. No gambling company, product or offer is named, rated or linked anywhere on the site, and nothing here is certified or assessed. These guides explain how the games work and why the arithmetic favours whoever sets the terms; they do not explain how to play, and they treat gambling as a subject rather than an activity to take up. [Read the full method note](https://get-certified.net/method/)