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Metal detectors in schools: the equipment is cheap. The people are not.
A walk‑through metal detector costs about what a used car does. Running it every school day, at every entrance, for every year, is where the budget goes. Here are the published numbers.
Equipment
What the hardware costs
| Item | Published price | Source |
|---|---|---|
| Conventional walk‑through metal detector | $1,500 to $15,000 per unit | Industry guides; the DHS market survey lists one passive portal at $15,000 |
| Passive ferromagnetic portal (CEIA OpenGate) | $15,000 to $25,000 per unit | Clarksville‑Montgomery County, TN, 2026; Newport News, VA, 90 units for $1.5M |
| Kenosha, WI: 18 OpenGate units plus 15 wands | About $473,000 | District purchase, 2026 |
| New York City: about 80 campuses | About $3.9M | Chalkbeat, 2024 |
| Handheld wand | $100 to $300 | Industry guides |
Sources: DHS SAVER market survey (2024) · WSMV · Kenosha County Eye · Chalkbeat
Staffing
Where the money actually goes
$250,000 a year, one school
Granite School District, Utah, pays a private security contractor $250,000 a year to run the scanners at one high school. The four‑year hardware lease was $280,000.
$10 million a year, ten schools
Douglas County, Colorado's security director estimated about $10 million a year, roughly 160 employees, to staff entry detectors with law enforcement at up to ten schools. The board turned the plan down in 2026.
Two to three staff per entrance
Every active lane needs a screener to resolve alarms, plus someone for the wand and the bag check. A single high school typically runs two to four lanes at arrival. Hours vary: Gwinnett County screens at morning arrival only; Kenosha screens all day.
A worked example. One 1,500‑student high school, four lanes, two staff per lane at $18 an hour for 180 school days: about $52,000 a year if the lanes run two hours at arrival, about $207,000 a year if they run all day. Over five years, with $60,000 of detectors, that is $319,000 to $1.1 million. If the lanes are staffed by school resource officers instead, two officers at $110,000 a year make it about $1.16 million. The chart.
What you get for it
They do find weapons. The evidence stops there.
New York City's scanning at about 80 campuses recovered 8 guns and 1,774 knives in 2023‑24. That is real. A systematic review in the Journal of School Health still found insufficient evidence that detectors reduce violent behavior, and several studies found lower student perceptions of safety where they are used. In the Secret Service's study of 41 attacks, three schools had detectors; they were not regularly used.
The gap is structural. A detector covers one lane while it is staffed. A propped side door, a weapon stashed on campus the day before, or an attacker who is already a student walks around it. Nine in ten school attackers are students of the school.
Chalkbeat · Hankin, Hertz & Simon (2011) · Secret Service NTAC (2019)
What the same money buys at the doors
One year of all‑day screening at one high school, about $207,000 in labor alone, is close to what sixty ClassLock doors cost installed. After that the doors cost $300 a door a year and nobody has to stand at them.
A locked classroom door does not need to know what someone is carrying. Across every major U.S. school attack since Columbine, no classroom lock was ever defeated. Every breach of a locked door went through glass.