The table below defines the different classes of lasers and LEDs according to the most recent versions of EN 60825-1 and IEC 60825-1. An Overview of the Laser Classification System provides a more detailed description.

Class 1	Safe.
Class 1M	Safe provided optical instruments are not used.
Class 2	Visible lasers. Safe for accidental exposure (< 0.25 s).
Class 2M	Visible lasers. Safe for accidental exposure (< 0.25 s) providing optical instruments* are not used.
Class 3R	Not safe. Low risk.
Class 3B	Hazardous. Viewing of diffuse reflection** is safe.
Class 4	Hazardous. Viewing of diffuse reflection is also hazardous. Fire risk.

*Optical instruments – binoculars, telescopes, microscopes, magnifying glasses (but not prescription glasses).

**Diffuse reflection – the reflection of radiation from a matt surface such as a wall.