Zero-Sum Game

What is a Zero-sum Game?

A zero-sum game is when two or more people are involved in a situation, like a game or a contest, and for one person to win something, someone else has to lose the same exact thing. Think of it like a pizza—there are only so many slices, so if one person takes half the pizza, everyone else has to share the rest. This is just like saying the total amount of pizza stays the same; it’s only the number of slices each person gets that changes. The name “zero-sum” comes from the idea that if you add up the winners’ gains and the losers’ losses, they cancel each other out, so the sum is zero.

This idea of winning some and losing some is something we see all the time, not just in games, but in real life, too. When it comes to getting a job, for instance, if one person gets hired, the others don’t. In a race, only one person can come in first place, while everyone else comes in after. This doesn’t mean the runners aren’t trying their best; it’s just how races work—there’s one winner and many who don’t win.

Definitions of Zero-sum Game

Let’s break it down further with two simple definitions:

1. Zero-sum Game in Context: When we talk about a zero-sum game in everyday life, we mean a situation where there is a fixed amount of something good or bad, like money, jobs, or points in a game, and the only way for one person to get more of that thing is for another person to get less. It’s like having a pie with eight slices: if you take three slices, only five are left for everyone else.

2. Technical Definition: In terms of game theory, a zero-sum game is a mathematical model in which each participant’s gain or loss of utility is exactly balanced by the losses or gains of the utility of the other participants. If the total gains of the participants are added up and the total losses are subtracted, they will sum to zero. In other words, in a competition, the prize is constant, and the competitors’ wins and losses add up to the value of the prize.

Examples of Zero-sum Games

  • Chess: In a chess match, when one player captures an opponent’s piece, the other player loses that piece. Hence, there is a clear winner and a loser by the end of the game, demonstrating the win-lose situation of zero-sum games.
  • Poker: At a poker table, the amount of money won by the winning players is equivalent to the total amount lost by other players. The winnings don’t come out of nowhere; they’re composed of the combined losses.
  • Stock Trading: When a trader sells a stock at a profit, there’s someone on the other side buying that stock who may incur a loss if the stock’s value goes down.
  • Resource Distribution: If a company has a limited budget for salaries, an increase in one employee’s salary might mean less is available for others.
  • Pie Eating Contest: Imagine there’s a contest with one pie. The more one person eats, the less pie there is for the other contestants. At the end, someone will win the contest, and others won’t win, and there’s no more pie to compete for.

Why is it Important?

Understanding zero-sum games can help us make sense of many situations in life where resources are limited. For example, during a drought, if farmers use more water for their crops, this means there is less water available for other uses. Knowing that this is a zero-sum situation can push people to find solutions that might avoid the problem, like developing drought-resistant plants or using water more efficiently.

In our daily lives, recognizing a zero-sum scenario could help us in decision-making and strategy, especially in competitive environments like sports, business, and academics. For example, students competing for the top rank in class are in a zero-sum competition; there can only be one valedictorian. This could motivate students to study harder, but it could also encourage them to collaborate and learn from each other, transforming what seems like a zero-sum game into a more cooperative situation.

Related Topics

  • Non-Zero-Sum Games: This is the opposite of zero-sum games. In non-zero-sum games, it’s possible for all the players to come out ahead or all to lose, like in a situation where companies work together to improve a market, raising sales for everyone involved.
  • Prisoner’s Dilemma: It’s a classic example where two individuals might not cooperate, even if it’s in their best interest to do so, because they can’t trust each other not to betray the other. It’s often used to describe why two people or groups might not cooperate even when it would be beneficial to do so.
  • Game Theory: This is the study of mathematical models of strategic interaction among rational decision-makers. It’s used in economics, political science, and psychology, as well as logic, computer science, and biology.
  • Nash Equilibrium: Found within game theory, this is a situation where, in a game, players have chosen their strategies and no player can benefit by changing strategies while the other players’ strategies remain unchanged.
  • Tragedy of the Commons: It’s a situation in which individuals, acting independently according to their own self-interest, behave contrary to the best interest of the whole group by depleting a common resource. This shows how individual incentives can lead to negative outcomes.

Importance to the Average Person and Life

Whether we know it or not, zero-sum games are part of our everyday life. For instance, when we apply for a single job opening, we are essentially in a zero-sum game with other applicants. Only one person can be hired, so our gain is their loss. Recognizing situations like this helps us prepare and strategize: we might work on our interview skills or gain additional qualifications to increase our chances of winning.

However, understanding zero-sum games is also a reminder not to treat every situation as a win-lose scenario. In some cases, like group projects or community efforts, working together can create new solutions where everyone benefits, turning a potential zero-sum game into a win-win situation. This kind of thinking encourages us to look beyond our immediate competition and consider collaborative opportunities that can lead to better outcomes for everyone involved.


In summary, a zero-sum game is a situation where for someone to win, someone else has to lose an equal amount. It’s a useful concept for making sense of competitive situations and can apply to various aspects of life including sports, business, politics, and resource management. However, it’s also important to recognize that not all situations are zero-sum games. By understanding this concept, we can better navigate the world, knowing when to compete and when to look for common ground and work together. Furthermore, seeing the big picture allows us to identify opportunities for collaboration, making it possible for everyone to benefit. Zero-sum games teach us about balance, choices, and the consequences of our actions in both the competitive and cooperative aspects of life.