M2 Calculator Calculate M2 from Beam Product Parameter (BPP) of the laser: Wavelength: nmum BPP: mm.mrad M2: 1.00 Beam Divergence Calculator Calculate beam divergence from beam diameter and M2: Wavelength: nmum Beam Diameter: mmum M2: Beam Divergence (full): 0.2709 mRaddeg M2 Calculator Calculate M2 and Rayleigh length from beam diameter and divergence: Wavelength: nmum Beam Diameter: mmum Beam Divergence (full): mRad Deg Rayleigh length: 18.52 meters M2: 1.00 M2 Calculator for fiber Calculate M2 from core diameter and N.A: Wavelength: nmum Core Diameter: mmum Numerical Aperture: M2: 65.49