Simple Room Lighting Calculator (Lumen Method)

Simple Room Lighting Calculator – Lumen Method

Fast, back‑of‑the‑envelope average illuminance using E = (N · Φ · UF · MF) / A. Draws a plan with luminaire symbols and spacing.
For teaching, sizing, and sanity‑checks – not a replacement for full point‑by‑point calcs.

Inputs

Room

Length L (m)

Width W (m)

Mounting height above workplane H_m (m)

Workplane height above floor (m) (for reference)

Luminaire & Method

Lumens per luminaire Φ (lm)

Maintenance factor MF

Utilization factor UF

Target E_avg (lux)

Spacing Criterion (SC) (optional)

Sizing mode

Quick UF estimator (optional)

Ceiling reflectance %

Wall reflectance %

Floor reflectance %

Uses a coarse generic curve (illustrative only).

Layout & Export

Wall margin factor (0.5 = half spacing)

Canvas height (px)

Results

Room Index K

Utilization UF

Luminaires N

E_avg (lux)

Grid:

Spacing X / Y (m):

SC limit S_max (m):

Top‑down plan. Luminaire symbols drawn at equal spacing with configurable wall margins. Dimensions shown in metres.