Power Density Calculator
Peak and average irradiance of a Gaussian beam from power and 1/e² diameter, with the beam area and the radial intensity profile.
Educational only — not compliance-grade
These pages implement the published exposure limits for the cases each one states, but they are educational tools: no laser safety officer has signed them off.
- Do not use these results alone for PPE selection, NHZ / NOHD approval, controlled-area sign-off, enclosure/interlock approval, or formal classification.
- Always verify against ANSI Z136.1, IEC 60825-1, your local procedures, and the responsible laser safety officer / CLSO.
Formulas
Gaussian peak: Epeak = 2P / (π w₀²) = 8P / (π d²)
Top-hat: E = P / (π r²) = 4P / (π d²)
Average irradiance: Eavg = P / A
Area: A = π (d/2)²
Input
Results
Peak Irradiance
254.65 W/cm²
Avg Irradiance
127.32 W/cm²
Beam Area
0.0079 cm²
Power
1 W
Radial Intensity Profile
Model and references
Exact. The equations are exact within the stated assumptions, or are a standard's tabulated values. The results are as good as the inputs. About the tiers
Closed forms for a round beam: Gaussian peak 2P/(πw²) = 8P/(πd²), mean over the 1/e² disc P/(πw²), top-hat P/A. Not modelled: aperture averaging for an MPE, clipping, non-Gaussian profiles.
- Saleh B. E. A., Teich M. C. (1991). Fundamentals of Photonics, ch. 3 (Beam Optics): Gaussian beam intensity and power. Wiley. doi:10.1002/0471213748