How to use the expected value calculator
- Odds — the price on offer, in any format (
2.30,+130,13/10). - Stake — what you'd bet.
- Your win chance — your honest estimate of how often this team wins.
You'll see the implied chance in the odds, your edge (expected return on stake), the EV per bet in dollars and your fair odds — the price at which the bet breaks even.
Example
A League of Legends underdog is priced 2.30 (implied 43.5%). After looking at the draft tendencies on this patch, you rate them at 48%. Stake $20:
| Value | |
|---|---|
| Edge | 0.48 × 2.30 − 1 = +10.4% |
| EV per bet | $20 × 0.104 = +$2.08 |
| Your fair odds | 1 ÷ 0.48 = 2.08 |
On average, each $20 bet like this returns $2.08 profit. But any single bet either wins $26 or loses $20.
How much your estimate matters
Same odds of 2.30, $20 stake, different estimates:
| Your win chance | Edge | EV per $20 |
|---|---|---|
| 40% | −8.0% | −$1.60 |
| 43.5% | 0.0% | $0.00 |
| 45% | +3.5% | +$0.70 |
| 48% | +10.4% | +$2.08 |
| 55% | +26.5% | +$5.30 |
A few points of win chance swing a bet from losing to winning. Big edges in esports are rare; if you think you have a 25% edge on a tier-one match, double-check the roster news first.
Where esports edges come from
- Patches and metas: a new patch can change which teams are strong before odds catch up.
- Map pools and vetoes: in CS2 and Valorant, the map often matters more than the team name. See the CS2 map pool and veto guide.
- Lower tiers: less-watched leagues are priced with less information — but also carry wider margins.
Example: a Dota 2 underdog
A Dota 2 team is priced at 2.60 and you rate its chance at 42%, after checking the patch, the draft style and recent form. You stake $20.
| Value | |
|---|---|
| Implied chance at 2.60 | 38.5% |
| Your estimate | 42.0% |
| Edge (ROI) | +9.2% |
| Expected value | +$1.84 |
| Your fair odds | 2.38 |
At 2.38 or longer the bet is worth taking by your own estimate, and at 2.60 you are getting extra. The result can still go either way in one match: a +9% edge loses more than half the time at these odds.
Keep a short log of your estimates. After 100 bets you can compare your 42% calls with how often they landed, which is the honest test of whether your read is any good.
Got a +EV bet? Size it with the Kelly calculator. To turn map odds into series odds first, use the series calculator.
