Earthquake early warning (EEW) is the rapid detection of earthquakes underway and the alerting of people and infrastructure in harms way. Public warning systems are now operational in Mexico and Japan, and smaller‐scale systems deliver alerts to specific users in Turkey, Taiwan, China, Romania, and the United States. The warnings can arrive seconds to minutes before strong shaking, and a review of early warning applications around the world shows this time can be used to reduce the impact of an earthquake by many sectors of society. Individuals can use the alert time to drop, cover, and hold on, reducing injuries and fatalities, or if alert time allows, evacuate hazardous buildings. Train derailments can be reduced, chemical splits limited, patients in hospitals protected, fire ignitions prevented; workers in hazardous environments protected from fall/pinch hazards, reducing head injuries and/or death. It is impossible to complete an exhaustive list of applications and savings generated by a warning system in the United States, but the benefits clearly outweigh the costs. Three lives saved, two semiconductor plants warned, one Bay Area Rapid Transit train slowed, a 1% reduction in nonfatal injuries, and a 0.25% avoidance of gas‐related fire damage would each save enough money to pay for 1 year of operation of a public warning system for the entire U.S. West Coast. EEW could also reduce the number of injuries in earthquakes by more than 50%.