What is considered a mass shooting?
The FBI defines an active shooter as an individual actively engaged in killing or attempting to kill people in a populated area, but the definition of mass shooting is less clear.
In the last several years, hundreds of shootings where multiple people were either injured or killed have been reported in the US. These events are confirmed by local and state law enforcement and covered in media outlets in communities across the country.
Stories about gun violence include terms such as “active shooter,” “mass shooting,” and “mass killing”. The terms can be easily confused because various organizations and government agencies define them differently.
What is a mass shooting?
Although the federal government lacks a widely accepted definition of “mass shooting,” the Federal Bureau of Investigation (FBI) has defined and tracked “active shooter” incidents since 2000. It classifies incidents with three or more fatalities as “mass killings,” a definition Congress adopted after the 2013 Sandy Hook Elementary School shooting in Newtown, CT.
What is an active shooter?
The FBI definition for an active shooter incident is: “one or more individuals actively engaged in killing or attempting to kill people in a populated area.”
Between 2000 and 2024, the FBI recorded 528 active shooter incidents, with the highest number in 2021. That year, 61 incidents left 140 people wounded and 103 killed, totaling 234 victims.
Active shooters incidents have dropped 61% since 2021.
Total active shooter incidents per year, 2000–2024
Although 2021 had the most incidents, 2017 saw the highest number of casualties, with 729 people wounded or killed.
In the last five years, 22% of active shooter events met the definition of a mass killing.
Between 2000 and 2024, active shooter incidents resulted in more than 1,300 deaths and 2,395 injuries.
Total number of persons killed or wounded in active shooter incidents
What is considered a gun-related death in the US?
The Centers for Disease Control and Prevention (CDC) tracks firearm-related deaths — the number of people “dying from a firearm-related injury.” This includes all deaths involving guns, such as homicide, suicide, and accidents.
While there isn’t a single government database dedicated to collecting all firearm-related incidents, there are data on firearm-related deaths in the US collected and collated from public health databases, fatal injury reports, and cause of death reports.
As of December 2024, provisional CDC data indicate that total firearm deaths were 4% lower than in the same month of 2023. After adjusting for age, 13 out of every 100,000 people died from firearm-related injuries in 2024.
In 2024, an estimated 44.4K people died from gun-related injuries.
Cumulative firearms deaths, data for 2024 is provisional
Since 1979, more people in the US die from suicide involving a firearm than homicides (including mass killings) or accidents.
Since 1979, suicide has been the leading cause of firearm deaths in the US.
Number of firearm deaths by intent and year, 1979–2023
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