Esports books present prices in different formats, but the underlying math is the same. Once you can convert between decimal and American odds and translate them into implied probabilities, you can compare markets, estimate bookmaker margin, and decide if a price is worth taking.
What the main odds formats mean
Decimal odds show total return per 1 unit staked. For example, 2.50 returns 2.50 per 1 staked, including stake. American (moneyline) odds use positive numbers for underdogs (+150 returns 150 profit on 100 staked) and negative numbers for favorites (−200 means stake 200 to profit 100). Both formats convert cleanly to probabilities.
Quick conversion formulas you’ll actually use
American to decimal: for positive numbers, decimal = 1 + (US/100); for negative numbers, decimal = 1 − (100/US). Decimal to American: if decimal ≥ 2.00, US = (decimal − 1) × 100; if decimal < 2.00, US = −100 ÷ (decimal − 1). Fractional and probability formulas follow the same pattern and are handy to verify results.
Implied probability is the percentage chance embedded in a price. For decimal odds it’s 1/decimal; for American odds it’s 100/(US + 100) when positive and |US|/(|US| + 100) when negative. This is the foundation for comparing prices across books and formats.
Reading esports markets quickly
Popular esports markets include match winner, map winner, map handicaps (for example, −1.5 in best-of-3), totals like over/under rounds in Counter-Strike 2, and player or team props. Enterprise feeds that power sportsbooks cover the major titles and in-play markets, then expose them to operators via APIs.
From prices to percentages to margin
Bookmakers build a margin (overround) into their prices. On a two-way market, convert each side to implied probability and add them; anything above 100% is the margin. The same method extends to three-way markets by summing the three implied probabilities.
A more general definition: implied probability equals stake divided by total payout; summing implied probabilities across outcomes shows how much “extra” is baked into the market.
Removing the vig (no-vig normalization)
To estimate “fair” probabilities, divide each outcome’s implied probability by the sum of all implied probabilities so the total becomes 100%. This simple normalization is commonly used to strip out the bookmaker’s edge before comparing to your model or another book.
Worked example: two-way CS2 match (decimal → no-vig → American)
Suppose Team A is 1.60 and Team B is 2.40.
Step 1: implied probabilities
Team A: 1/1.60 = 0.625 (62.5%)
Team B: 1/2.40 ≈ 0.4167 (41.67%)
Sum = 0.625 + 0.4167 ≈ 1.0417 → market margin ≈ 4.17%.
Step 2: remove the vig
Fair pA = 0.625 ÷ 1.0417 ≈ 0.6000 (60.0%)
Fair pB = 0.4167 ÷ 1.0417 ≈ 0.4000 (40.0%).
Step 3: back to fair odds
Decimal: A = 1/0.60 ≈ 1.6667, B = 1/0.40 = 2.50.
American: A (decimal < 2): −100 ÷ (1.6667 − 1) ≈ −150; B (decimal ≥ 2): (2.50 − 1) × 100 = +150.
Three-way example (regulation market)
If a regulation market lists 2.10, 3.20, 3.40, first convert to implied probabilities: 1/2.10 ≈ 47.62%, 1/3.20 = 31.25%, 1/3.40 ≈ 29.41%. Sum ≈ 108.28% (margin ≈ 8.28%). Normalize each by 108.28% to get fair probabilities of roughly 43.98%, 28.86%, and 27.16%, then invert to fair decimals ≈ 2.27, 3.46, and 3.68. Same method, just three outcomes.
Crypto-friendly ways to build with odds and data
If you’re integrating esports odds or building tools for crypto bettors, these options are widely used:
PandaScore odds and data APIs provide pre-match and in-play markets and statistics across major titles, with commercial plans and documentation for coverage, pricing tiers, and usage limits.
Oddin.gg offers an esports odds feed, risk management, and SDKs that operators embed to power live markets and engagement features; recent releases and partnerships show wide B2B adoption.
Cloudbet, a long-running crypto sportsbook, exposes a public Trading API that supports placing bets and fetching markets, with documentation and currency support that includes BTC, ETH, USDT and others. This is a direct way to build crypto-native apps that interact with a live book.
Implementation tips that save time
Always read the game or match info panel for the posted RTP or rule quirks in casino titles and the official market definitions in sportsbooks. For pricing work, cache odds briefly, respect API rate limits, and standardize everything internally as decimal with probabilities so you can compare feeds consistently. If you strip vig, document which no-vig method you use so results are reproducible across two-way and three-way markets.
Legal and responsible-play note
Online gambling laws vary by country. For readers in Malaysia, the Court of Appeal ruled on October 18, 2023 that online gambling is an offence under the Common Gaming Houses Act 1953, and the regulator has reported extensive blocking of gambling websites. Obey local law and use licensed providers only where permitted. If gambling affects your wellbeing, seek confidential help.
Frequently asked questions
Which odds format is best for esports?
Decimal is easiest for quick math because 1/decimal gives implied probability instantly. Moneyline is common in the U.S., but both convert back and forth without loss.
What’s the fastest way to check if a price is fair?
Convert the market to implied probabilities, add them to see the margin, then normalize to 100% to get no-vig probabilities and invert back to fair odds. For two-way markets, the math is especially quick.
Where do esports operators get their odds?
Most books license a B2B esports feed or build in-house. PandaScore and Oddin.gg are two prominent suppliers; crypto-native apps can also integrate a sportsbook API like Cloudbet’s.
Does using crypto change the odds or payout math?
No. Currency affects deposits, withdrawals, and settlement, not the underlying probabilities or conversions. The same decimal and American math applies everywhere.
