A comprehensive resource for safe and responsible laser use
Laser Classes chart
Lasers are classified based on their potential for causing injury — especially eye damage, since the eye is most susceptible to excess laser light.
There are four main classes for visible-beam lasers: Class 2, Class 3R, Class 3B and Class 4. The first two are relatively safe for eye exposure; the last two are hazardous. The chart below shows that the eye injury hazard increases as the laser’s power increases.
Click chart for larger view
The detailed information given below is for laser light that is visible -- between 400 and 700 nanometers -- and for an unintentional exposure of less than 1/4 second. Consult other sources for classifications of infrared and ultraviolet lasers, or other visible-light exposure durations.
Laser Classes (visible light only, unintentional exposure)
Click table for larger view. Thank you to Josh Hadler for info updated April 2023.
For more information about a particular class, click here: __ Class 2 __ Class 3R __ Class 3B __ Class 4
For information about laser classifications in general, see this page from Rockwell Laser Industries.