Lighting Calculators
Free tools for the numbers our customers ask for most — beam coverage, fixture counts and container loading — with every formula and assumption stated.
Quick Estimates, Stated Assumptions
These calculators are for rough project scoping. Every result states the formula it used, because the difference between a lighting estimate and a lighting design is knowing where the assumptions sit. For final values — especially beam spread under a specific fixture, or dimming compliance for museums and galleries — use the photometric IES data and our published verification or ask our engineering team.
Beam Coverage & Illuminance
Given a beam angle and mounting height, estimate the spot diameter and the average lux on the floor. Assumes a uniform beam and a flat surface at the mounting distance.
D = 2 · d · tan(θ/2), A = π·(D/2)², E ≈ Φ/A — flat surface only; real fixtures with non-uniform optics will differ. See beam comparison in our COB vs SMD guide.
Fixture Count Estimation
How many fixtures for a target lux level? Uses the Lumen Method — N = E·A / (Φ·UF·LLF) — with a utilization factor for the room surface and a light-loss factor for depreciation.
N = E·A / (Φ·UF·LLF), rounded up. UF and LLF estimates — for a real design use IES photometrics ( see lighting design guidance ).
Container Loading Estimate
How many cartons fit in a 20GP or 40HQ export container? Tries all six box orientations, then takes the lower of the volume limit and the payload weight limit.
Payload weight limit reached — fewer cartons fit than the volume allows. Groupage or a lighter carton spec may improve the fill.
Floor-packing only (no pallets), 1–2 cm clearance is not deducted — treat as an upper bound. Contact us for a confirmed stow plan when the carton spec is final.
Why We Publish These
Buyers routinely ask how many fixtures a room needs before they ask which fixture. These three calculations were the most-requested numbers in our own project correspondence, so we published them with their math — the same way we publish our 24V vs 48V voltage-drop bench test and the engineering guides in our knowledge base.
Need the number for a real project?
Send us the room dimensions, the target lux, and the application. The engineering team turns it into a fixture schedule with IES files — free.
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