Payoff Matrix Calculator
Change the incentives. See who wants to move. Explore pure and mixed Nash equilibria in a two-player, two-strategy game — free, without signing in.
Both prefer meeting to missing each other, but disagree about which plan to choose.
Analyzed game
Different plans
A boxed cell is a pure Nash equilibrium. Underlining marks a best response, including ties. Payoffs are in points.
| Concert | Cinema | |
|---|---|---|
| Concert | 3,2 Best response for Alex. Best response for Sam. Nash equilibrium | 0,0 |
| Cinema | 0,0 | 2,3 Best response for Alex. Best response for Sam. Nash equilibrium |
2 pure Nash equilibria
In each boxed cell, neither player gains by switching alone. An underline may tie another payoff: a best response need not be unique.
All equilibrium probabilities
p = probability Alex chooses Concert. q = probability Sam chooses Concert. The other strategy gets 1 − p or 1 − q.
- p = 1; q = 1
- p = 0; q = 0
- p = 3/5; q = 2/5
An interval includes both endpoints. Every combination within a listed pair of intervals is an equilibrium; the full list includes pure and mixed strategies.
Why randomize? Try a mixture.
Move one player’s probability and watch the other player’s incentives change. These are trial choices, not necessarily an equilibrium. They do not alter your game or lesson. Interactive controls require JavaScript.
Sam’s expected payoff for each pure strategy
- Concert
- 1.00 points
- Cinema
- 1.50 points
Alex’s expected payoff for each pure strategy
- Concert
- 1.50 points
- Cinema
- 1.00 points
What this calculator does — and does not tell you
A Nash equilibrium is a pair of strategies where neither player can improve their expected payoff by changing alone. It need not be fair, best for the pair, or a prediction of what students will actually choose.
This solver covers two players with two strategies each, including ties, weak best responses and infinitely many equilibria. It assumes each player maximizes their stated numerical payoff. It does not solve larger games, sequential games or repeated-game incentives.
The mixed-strategy calculation makes each player indifferent between the strategies they randomize over. Equilibrium probabilities are exact reduced fractions; the optional trial-mixture display is rounded.
For a worked mathematical introduction, see MIT’s mixed-strategy lecture. Ready to teach? Explore game theory classroom activities, then use the exact analyzed game below.
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