Tournament
Bubble factor
For an all-in where the smaller stack is at risk. Bubble factor = equity lost if you lose ÷ equity gained if you win. Needed equity = loss ÷ (loss + gain), before blinds and antes in the pot.
A bubble factor calculator shows how much more you need to call an all-in when the money is on the line. Four players left, three paid 50/30/20, and you have 3,000 chips. Against the 4,000 chip leader the free calculator above gives a bubble factor of 2.69. Losing would cost 2.69 times what winning would gain, so you need 72.9% equity to call, not the 50% a cash game would ask for.
Bubble factor calculator: what the number means
Bubble factor = ICM equity lost if you lose ÷ ICM equity gained if you win. It uses the Malmuth-Harville model, the same one in the ICM calculator. Turn it into a calling threshold with:
Equity needed = BF ÷ (BF + 1)
| Bubble factor | Equity needed (before blinds) |
|---|---|
| 1.0 | 50% |
| 1.2 | 54.5% |
| 1.5 | 60% |
| 2.0 | 66.7% |
| 3.0 | 75% |
In the example, the same 3,000-chip player has a bubble factor of 1.48 against the 2,000 stack and 1.16 against the short stack. Big stacks hurt you most because they can knock you out; short stacks can only take part of your chips.
Using it at the table
- Calling: compare your hand’s equity against the opponent’s likely range with the threshold, not with 50%.
- Shoving: the bubble factor works on the other side too. Players with high bubble factors against you have to fold more, which makes your shoves better.
- Blinds and antes in the pot lower the threshold a little. The figures here leave them out.
Short-handed with under 20 big blinds, the push/fold chart gives the Nash ranges, and the poker odds calculator tells you a hand’s equity against a range.
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