Do your laser glasses actually cover your laser?
Pick your machine, then type the label printed on your glasses. The checker tells you whether every wavelength your machine can fire is inside a protected band, and roughly what optical density (OD) it needs — including the second, invisible infrared laser on dual-laser machines.
1Your laser
2Your glasses
| Laser | Covered? | OD needed | Glasses give |
|---|
Two questions, in this order
- Is every wavelength covered? Glasses protect only inside the bands printed on them. “Close” does not count: MIT’s laser safety office gives the example of eyewear rated OD 4+ at 435 nm that drops to about OD 2 at 445 nm and below OD 1 at 455 nm. The checker requires the whole tolerance band of your laser (for example 445 ± 15 nm) to sit inside one printed band.
- Is the OD high enough? Optical density is the power of ten by which the glasses cut the light: OD 5 lets through 1/100,000. The checker estimates the OD needed to bring a direct hit by the raw beam below the eye’s exposure limit.
How the required OD is estimated
Exposure limits (MPE) come from the ICNIRP 2013 guidelines, which IEC 60825-1:2014 follows, for a continuous beam from a small source. If the beam is narrower than the aperture, all of its power counts, which is why a blank beam diameter means “worst case”. The 0.25 s option is the blink-reflex case and only applies to visible light; infrared and CO2 beams are invisible, so they always use at least 10 s.
Worked examples
| Laser | Irradiance | Eye limit | log10 | Round up |
|---|---|---|---|---|
| 10 W blue diode, 455 nm | 26 W/cm² (7 mm) | ≈ 0.001 W/cm² (10 s) | 4.4 | OD 5 |
| 2 W infrared, 1064 nm | 5.2 W/cm² (7 mm) | ≈ 0.005 W/cm² (10 s) | 3.0 | OD 4 |
| 55 W CO2, 10.6 µm | 572 W/cm² (3.5 mm) | 0.1 W/cm² (10 s) | 3.8 | OD 4 * |
* At CO2 power levels the beam can burn through eyewear before OD matters. MIT’s guidance notes that ANSI does not recommend relying on eyewear above about 100 W or 200 W/cm². The closed lid and interlock are the protection; glasses are for low-power work with the lid open.
Reading the label
OD labels (US style)
A label such as OD5+ 190–540 nm means at least OD 5 everywhere from 190 to 540 nm. Several bands may be printed, for example OD5+ 190–540 nm & OD5+ 900–1100 nm. An OD figure says how much light is blocked, not whether the lens survives a direct hit by a powerful beam.
EN 207 labels (European)
EN 207 markings look like D 445 LB5 or 800–1090 D LB6 + IR LB7. The letters are laser modes:
| Letter | Mode | Pulse length |
|---|---|---|
| D | Continuous wave | over 0.25 s |
| I | Long pulse | 1 µs – 0.25 s |
| R | Q-switched | 1 ns – 1 µs |
| M | Mode-locked | under 1 ns |
“IR” on an EN 207 label is not “infrared”. It means the I and R pulsed modes. D LB6 + IR LB7 is LB6 for continuous output and LB7 for pulses, over the wavelength range printed with it.
LBn means an OD above n at that wavelength, plus a test in which the filter and frame must withstand a direct hit for 5 seconds (continuous) or 50 pulses. That is why an LB rating is a firmer guide than OD alone, and why the checker never gives a green result to an OD-only band once the beam is above about 1 W/cm². RB ratings come from EN 208 and are for alignment: they deliberately let a little visible light through and are not protection for engraving. A CE mark on its own does not tell you which wavelengths were tested.
Dual-laser machines
Some machines carry a blue diode and an infrared laser in one head. The infrared beam is invisible, gives no blink reflex, and passes through many blue-laser glasses. xTool’s goggle guide lists every wavelength its goggles must cover for each machine, including a red 650–655 nm wavelength, and the OD it recommends (the checker uses these OD values as a minimum):
| Machine | Lasers | What xTool says |
|---|---|---|
| xTool F1 | 445 ± 15 nm diode, 1064 ± 5 nm infrared, 655 ± 5 nm | Class 4. Goggles must cover all three; OD5+ recommended. |
| xTool F1 Ultra | 445 ± 15 nm diode, 1064 ± 5 nm fiber, 655 ± 5 nm | Class 1 or Class 4 depending on version; OD6+ recommended for the Class 4 model. |
| xTool F2 Ultra (dual) | 445 ± 15 nm diode, 1064 ± 5 nm MOPA, 655 ± 5 nm | Class 4. Goggles not in the box; OD6+ recommended. |
| xTool S1 (Class 4 setup) | 455 ± 5 nm diode, 1064 ± 5 nm infrared module, 650 ± 5 nm | Class 1 normally; Class 4 with the riser base and conveyor. OD6+ recommended for the Class 4 model. |
| xTool P2 / P2S (Class 4 model) | 10.6 µm CO2, 650 ± 5 nm, 455 ± 5 nm | Goggles must cover all three; OD5+ recommended. |
Many 1064 nm galvo modules are pulsed. For a pulsed laser the checker only gives an average-power estimate; look for an EN 207 I or R rating at 1064 nm, or follow the maker’s recommendation.
Enclosed machines and CO2 lids
A machine can be sold as Class 1 because its Class 4 laser is sealed inside an interlocked enclosure. With the lid shut, no glasses are needed. The rating changes when you open the lid while it can fire, fit a riser or pass-through, or defeat the interlock. Clear polycarbonate can absorb 10.6 µm strongly, and CO2 filters with high OD at 10,600 nm are sold in clear polycarbonate, but clear lenses do nothing for a blue diode or infrared laser, and only a labelled, tested product gives you a rating.
FAQ
- What OD do I need for a 10 W blue diode laser?
- As a rough worst-case guide for 10 seconds of exposure, about OD 5 at 445–455 nm (OD 6 if you plan for 100 seconds). A 10 W beam into a 7 mm pupil is about 26 W/cm²; the eye limit for 10 s at 455 nm is about 0.001 W/cm², so OD = log10(26 ÷ 0.001) ≈ 4.4, rounded up to 5. Use your laser maker’s recommendation if it is higher.
- Do blue laser glasses protect against a 1064 nm infrared laser?
- Only if the label lists a band that covers 1064 nm. Glasses for blue diodes are often rated something like 190–540 nm and give no stated protection at 1064 nm. Dual-laser machines such as the xTool F1 need glasses rated for both wavelengths.
- What does “IR LB4” mean on EN 207 laser glasses?
- In EN 207 the letters are laser modes, not colours: D is continuous wave, I is long pulse, R is Q-switched and M is mode-locked. “IR LB4” means level LB4 for I and R pulsed modes. It does not mean infrared. LB4 means the filter has an OD above 4 at that wavelength and also survived a direct-hit test.
- Do I need safety glasses for an enclosed Class 1 laser engraver?
- Not while the lid is closed and the interlock works: that is what makes it Class 1. You do need glasses rated for its wavelengths if you open the lid while it can fire, add a riser or pass-through that changes its class, or bypass the interlock.
Sources
- ICNIRP, Guidelines on limits of exposure to laser radiation (2013) — exposure limits, correction factors and limiting apertures.
- MIT EHS, Laser eye protection guidelines — OD formula, rounding up, the 435/445/455 nm example, ANSI note on high power.
- Drexel University EHS, Protective eyewear.
- Laser 2000, EN 207, EN 208 and ANSI explained; Lasermet, EN 207, CE marking and laser protective eyewear; Trinity College Dublin, EN 207/208.
- xTool support: choosing laser safety goggles (including the goggle label used in the example button), and the machine pages linked in the table above.
- Lasermate, CO2 filter (clear polycarbonate rated at 10,600 nm).
This checker is a rough guide for hobby and small-shop users. It assumes a direct hit by the raw beam and simplified exposure limits. It is not a substitute for the laser maker’s instructions, the glasses maker’s data or a laser safety officer.
Last checked 2026-10-27 · Calculated values; no laser was used to make this page. See also what not to laser cut.