Why odds matter in esports
Esports odds are just price tags on probabilities. The numbers reflect the market’s view of how likely each outcome is, plus a built-in margin for the bookmaker. Being able to translate odds into implied probability—and to see the margin—lets you compare lines, evaluate risk, and avoid overpaying.
Odds formats at a glance (and how to convert them)
- Decimal odds (e.g., 1.80): implied probability = 1 / 1.80 = 55.56%.
- Fractional odds (e.g., 5/2): implied probability = 2 / (5 + 2) = 28.57%.
- American/moneyline odds:
- +150 → implied probability = 100 / (150 + 100) = 40.00%
- −150 → implied probability = 150 / (150 + 100) = 60.00%
These conversions are industry-standard and work the same whether you’re pricing CS2 maps or LoL props.
Bookmaker margin (overround): finding the “vig”
If you convert every selection in a market to implied probabilities and add them up, you’ll usually get more than 100%. That excess is the margin (also called overround or “vig”). Example (two-way market): margin% = (100/oddsA + 100/oddsB) − 100. Smaller margins mean better long-term value for the bettor.
Game-by-game: how formats shape markets
CS2 (Counter-Strike 2)
CS2 regulation uses MR12 (12 rounds per half). First to 13 rounds wins the map; overtime follows at 12–12. Expect Bo1/Bo3/Bo5 series depending on tournament stage.
Common CS2 markets include match/map winner, total rounds (over/under), round handicaps (e.g., −3.5), pistol round winner, correct score, and overtime yes/no. Handicaps and round totals line up naturally with the 13-round win condition.
Practical read: because MR12 compresses scoring, small round edges matter more; pistol rounds can swing early economy and momentum.
League of Legends (LoL)
LoL is 5v5 on Summoner’s Rift; tournaments often use Bo3 in earlier phases and Bo5 in playoffs. Beyond match or map winner, books offer objective-focused props such as first blood, first turret, first dragon, and first Baron. These markets track early-game advantages and objective control rather than the final result.
Objective context: Baron Nashor is the flagship neutral; slaying it grants “Hand of Baron,” a powerful team buff that enhances pushing power and recall—key to closing games and thus priced into live odds.
Dota 2
Like LoL, Dota 2 series are typically Bo2/Bo3 in league play and Bo3/Bo5 in playoffs. Popular props include first blood, first tower, total kills, and first Roshan (which grants Aegis of the Immortal to help secure map control). Drafts and tempo picks (e.g., Ursa/TA) can move Roshan markets noticeably.
Valorant
Valorant maps are first to 13 rounds, with sides swapping after 12. At 12–12, competitive modes use structured overtime; teams must win by two (Premier has its own specific OT rules). This round-based structure underpins markets like total rounds, round handicaps, pistol rounds, and map winner.
Worked examples (so you can sanity-check any price)
- American to %: +150 in Valorant pistol market → 100/(150+100) = 40.00% implied.
- Decimal to %: 1.62 on a CS2 map favorite → 1/1.62 = 61.73% implied.
- Fractional to %: 7/4 on Dota 2 first Roshan → 4/(7+4) = 36.36% implied.
These are implied, not “true,” probabilities—the margin is still in there. Compare books by converting both sides and checking which one keeps the total closer to 100%.
Margin example (two-way market)
Suppose a LoL match winner market shows 1.80 vs 2.05.
Implieds: 55.56% and 48.78% → sum 104.34% → margin ≈ 4.34%. Another book posting 1.83 vs 2.00 sums to ~103.05%, i.e., lower vig and (usually) better long-term value.
Title-specific tips by game
- CS2: Totals and handicaps hinge on map pool and sides; MR12 increases the leverage of pistol/early gun rounds, so watch team pistol win rates and CT/TT split by map.
- LoL: Objective props price in early tempo and jungler influence; patch notes and meta changes (dragons, Baron variants, early objective pacing) can change how books shade lines.
- Dota 2: First Roshan/first tower props react to drafts; line moves after hero reveals can offer value if you’re quick.
- Valorant: Round-based markets (totals, OT) correlate with map tendencies and agent comp styles; understand OT rules so you’re not surprised by long deuce sequences.
Quick glossary
- Moneyline/American odds: positive numbers show profit on a 100-unit stake; negatives show how much you must stake to profit 100.
- Over/Under (Totals): bet on whether rounds, kills, or maps exceed a bookmaker-set number.
- Handicap/Spread: the book adds/subtracts rounds, kills, or maps to balance mismatches (e.g., CS2 −3.5 rounds).
- Overround/Margin/Vig: the amount by which a market’s implied probabilities exceed 100%.
FAQ
What does +150 mean in esports odds?
It’s American odds indicating a 100 unit stake returns 150 profit (total return 250). Implied win chance is 100/(150+100) = 40%.
Are decimal, fractional, and American odds different prices?
They’re just different ways to express the same thing; you can convert freely between them and back to implied probability.
How do I tell which sportsbook has the “best” line?
Convert each side to implied probabilities, add them, and prefer the book with the lower total (lower margin). Then pick the single best price for your selection across books.
Why do CS2 totals and handicaps look tighter now?
With MR12 (first to 13), each pistol/gun-round swing has more impact on the final score than in MR15, so books shade lines accordingly.
What makes LoL and Dota prop markets unique?
Objective-centric bets—first blood/tower/dragon/Baron in LoL; first blood/tower/Roshan in Dota—price early tempo, draft, and objective control rather than only the match result.
On safety and legality
Only bet where it’s legal and regulated in your jurisdiction, set hard limits, and treat wagering as entertainment. If betting no longer feels fun, seek support (e.g., your local problem-gambling helpline).
