Enter a beam angle and throw distance to see how wide the beam lands — its diameter and lit area. Drag the sliders and watch the cone update.
| Angle | Typical use |
|---|---|
| 8–15° | Accent & artwork, narrow spot |
| 20–25° | Spot lighting, retail display |
| 36–40° | General accent, kitchen island |
| 55–60° | Flood, ambient fill, wall washing |
| 90°+ | Wide flood, low ceilings |
Working backwards instead? If you know the pool size you want and need to pick an optic, use the Beam Angle Calculator.
Worked example: a 24° beam thrown 3 m lands a pool 2 × 3 × tan(12°) = 1.28 m wide, covering about 1.3 m².
Calculating beam spread
Beam spread is how wide a fixture’s light lands at a given distance, set by the beam angle and the throw. The geometry: beam diameter ≈ 2 × distance × tan(beam angle ÷ 2). A 24° beam at 3 metres lands a circle about 1.3 metres across; a 60° beam at the same distance spreads to roughly 3.5 metres. So doubling the distance doubles the diameter, and a wider angle widens it proportionally.
Use beam spread to plan coverage and fixture spacing: for even light, set spacing so adjacent beams overlap rather than leaving dark gaps. Remember the trade-off — for a fixed lumen output, a narrow beam gives a small, intense pool (high candela) and a wide beam a large, dimmer one. Pick the beam angle from the effect you want (tight accent vs broad wash) and the mounting distance to the surface.