Beam Angle Calculator
Welcome to our lighting beam angle calculator! A helpful tool for all lighting professionals, it works out the beam angle, spot width or throw distance for your lighting fixtures. Simply choose the value you want to solve for, enter the other two values, and the calculator will do the rest.
We're here to help with your lighting projects. Call our experts on 01525 850085 to discuss your requirements.
Formulae & assumptions
- Spot width: D = 2 · L · tan(θ/2)
- Beam angle: θ = 2 · arctan(D / (2L))
- Throw distance: L = D / (2 · tan(θ/2))
θ in degrees, L (distance) and D (spot width) in metres or feet. Results rounded sensibly.
A popular tool for:
