For a final call with no rake, break-even equity equals the cost of your call divided by the final pot after that call.
Required equity = call ÷ final pot
A complete example
The pot is 100. Your opponent bets 50, so you now face 150. Calling costs 50 and makes the final pot 200. Required equity is 50/200 = 25%.
The common mistake is dividing by 150. That leaves your own call out of the pot you would contest.
Try the numbers
50 ÷ 200 = 25.0% required equity
Illustration assumes a final full call, no further betting and no rake. Tournament prize equity is a separate question.
Equity is not the probability of improving
A card that completes your draw can still leave you with the losing hand. Equity describes your expected pot share against particular opposing hands or ranges, including ties.
When the simple formula is not enough
Future betting, imperfect equity realization, rake and tournament payouts can change the decision. The calculation shows a price under stated assumptions; it is not an automatic recommendation to call.
How this connects to expected value
Against a pot of 150, a 50 call with 30% equity has chip EV of 0.30 × 150 − 0.70 × 50 = +10. That is an average relative to folding at this decision, not a guaranteed outcome.