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CS2 Major and betting math: Swiss stage, Bo1 and Bo3
Move the slider to set how often Team A wins one map. The tool shows the series chance in Bo1, Bo3 and Bo5 and the path through a CS2 Major.
Team A wins a single map 55.0% of the time, so it takes the Bo3 about 57 times in 100 (a Bo1 would give it 55.0%).
Bo1 vs Bo3 vs Bo5
Exact map score
| Map score | Chance | Fair price |
|---|---|---|
| Team A 2–0 | 30.3% | 3.31 |
| Team A 2–1 | 27.2% | 3.67 |
| Team B 1–2 | 22.3% | 4.49 |
| Team B 0–2 | 20.2% | 4.94 |
Map handicap
Total maps
Swiss stage: 3 wins in, 3 losses out
Against opponents it beats 55.0% of the time per map, Team A gets through about 61 times in 100. If every Swiss match were a Bo1, it would be 59.3%: the longer decisive matches protect the stronger team.
Playoffs: 8 teams, single elimination, Bo3
From the last Swiss stage to the trophy: 11.7%. This keeps the same chance against every opponent; in reality the opponents usually get stronger each round, so read it as an optimistic guide.
How it is calculated
A match: every map is independent with the same chance for Team A; a best of three needs two map wins, a best of five three.
Swiss stage: we follow every record from 0–0 until the team reaches the wins it needs or the losses that knock it out. A match is decisive when a win would send the team through or a loss would knock it out; those use the longer format, the rest the shorter one.
Playoffs: the chance to win one series multiplied once per round.
Series and map handicap calculator →Dota 2 team ratings →League of Legends series math →Margin and no-vig calculator →
Major format: Valve – CS Major Supplemental Rulebook.
CS2 Major format, stage by stage
- Stage 1: Swiss16 teams. 3 wins advance, 3 losses eliminate.
- Stage 2: SwissAnother Swiss stage of 16 teams with the same win and loss rules.
- Stage 3: SwissThe last Swiss stage of 16 teams. The 8 teams that advance go to the playoff.
- Playoff: single eliminationA bracket of 8 teams. Every match is best of three. A loss ends the run.
Swiss stage: which matches are Bo3
| Swiss match | Format | What is at stake |
|---|---|---|
| Advancement match | Bo3 | A win sends the team to the next stage |
| Elimination match | Bo3 | A loss knocks the team out |
| Advancement and elimination match (one team advances, the other is out) | Bo3 | A win advances, a loss eliminates |
| All other Swiss matches | Bo1 | The record changes, nobody advances or leaves yet |
From Valve's Major Supplemental Rulebook. The tool above uses this split to build the Swiss record.
Bo1 vs Bo3: how much luck
Bo1: one map
- One map decides the match
- A team at 55% per map wins the match 55.0% of the time
- The weaker team needs only one good map
- Used for Swiss matches that do not decide advancement or elimination
Bo3: first to two maps
- A bad map can be fixed on the next one
- The same team wins the series 57.5% of the time
- A Bo5 stretches the same edge to 59.3%
- Used for advancement, elimination and all playoff matches
Map markets in a Bo3 series
Match winner
57.5%Who wins the series. With 55% per map, Team A takes a Bo3 this often.
Exact score 2–0
30.3%Team A wins both maps. The tool shows the chance of every exact map score.
Team B +1.5 maps
69.7%Team B wins at least one map. Team A −1.5 maps is the same as a 2–0 score.
Total maps over 2.5
49.5%The series goes to a third map: each team takes one of the first two.
Compare with the price
A bookmaker's price includes a margin. Remove it before comparing it with these chances.
Sources
Questions
What is the CS2 Major format?
Three Swiss stages of 16 teams, then a single elimination playoff of the 8 teams that advance from Stage 3. In Swiss, 3 wins advance and 3 losses eliminate.
Are CS2 Major matches best of one or best of three?
Both. In Swiss, advancement and elimination matches are best of three, all other matches best of one. All playoff matches are best of three, according to Valve's rulebook.
Why does a favourite win a Bo3 more often than a Bo1?
More maps mean one bad map matters less. A team at 55% per map wins 55.0% of Bo1 matches and 57.5% of Bo3 series. See esports betting explained.
Does the calculator use CS2 rankings?
No. You set the single-map chance yourself. Rankings can help you choose it, but the result is only as good as that input. The same series math works for Dota 2.
Is betting on the CS2 Major legal in Canada?
The answer depends on the laws of your province; this page is not legal advice. See esports betting in Canada for what to check.