Visual Interior Tool

Truly free

Free quick room lumen calculator

Free tier & pricing

Completely free web lumen-method calculator for a rectangular room; gives average illuminance and fixture spacing only, not full point-by-point analysis.

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Last verified Jun 23, 2026. Report a change →

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The short answer

Browser tool that performs lumen-method calculations for a rectangular room to estimate fixture quantity, spacing and illuminance. No install or login.

The facts

Pricing: Free · Truly free
Free tier: Yes
Runs in browser: Yes
Platforms: Web
2D / 3D: No 3D
Learning curve: Moderate
Export formats: —

The catch

Browser only — no offline app.
Designs only with this brand’s own catalog.

Best for

Quick interior fixture-count estimates