Wavenumber Calculator
σ = 1/λ, k = 2π/λ
Instructions
Enter wavelength in nanometers. The tool outputs both spectral wavenumber (cm⁻¹) and angular wavenumber (rad/m).
Formula
σ = 1/λ
k = 2π / λ
Common Questions
Which should I use?
Spectroscopy often uses cm⁻¹; wave physics commonly uses angular wavenumber in rad/m.