---
title: "Necessary vs. Sufficient Condition"
description: "A necessary condition must be present for an outcome to occur; a sufficient condition guarantees the outcome on its own. A condition can be one, both, or neither."
last_updated: "2026-08-02"
---

# Necessary vs. Sufficient Condition

A necessary condition must be present for an outcome to occur; a sufficient condition guarantees the outcome on its own. A condition can be one, both, or neither.

*Example: Oxygen is necessary for a fire but not sufficient; you also need fuel and a spark.*

## Sitemap

See the full [sitemap](https://www.criticalthinkingexercise.org/sitemap.md) for all pages.