Lighting Beam Spread Calculator
From a fixture's beam angle and throw distance, get the beam diameter at the target — for hanging and focusing fixtures precisely.
A 26° fixture at 8 m throws a ~3.7 m pool of light. Knowing the beam diameter before you focus lets you pick the right lens/zoom and hang position to cover a performer or set piece exactly — the difference between a clean special and spill all over the next area.
Rule / Formula
From a fixture's beam angle and throw distance, get the beam diameter at the target — for hanging and focusing fixtures precisely.
About Lighting Beam Spread Calculator
From a fixture's beam angle and throw distance, get the beam diameter at the target — for hanging and focusing fixtures precisely. A 26° fixture at 8 m throws a ~3.7 m pool of light. Knowing the beam diameter before you focus lets you pick the right lens/zoom and hang position to cover a performer or set piece exactly — the difference between a clean special and spill all over the next area.
How to use Lighting Beam Spread Calculator
- 1Enter your values into the fields in Lighting Beam Spread Calculator.
- 2The result and any pass/fail verdict update instantly as you type — no button to press.
- 3Check the substituted formula and worked example to see exactly how the result was derived.
- 4Copy or note the result for your spec, delivery or planning.
Why use Lighting Beam Spread Calculator?
- ✓Runs entirely in your browser with instant, private results — no data leaves your device.
- ✓Built on a published reference: Photometric beam-angle geometry.
- ✓Shows the governing formula and a worked example, so you can trust and check every result.
- ✓100% free with no sign-up, no watermark and no usage limits.
- ✓Works on any device — desktop, tablet or phone — and keeps working offline once loaded.
Frequently asked questions
What does Lighting Beam Spread Calculator do?+
From a fixture's beam angle and throw distance, get the beam diameter at the target — for hanging and focusing fixtures precisely. A 26° fixture at 8 m throws a ~3.7 m pool of light.
Is my data private?+
Yes. Lighting Beam Spread Calculator runs entirely in your browser — your inputs are never uploaded, stored or logged.
What standard or source is Lighting Beam Spread Calculator based on?+
It follows Photometric beam-angle geometry. Always confirm against the current official document, as specifications and rates can change.
What formula does it use?+
Lighting Beam Spread Calculator uses: beam diameter = 2 × throw × tan(beam angle ÷ 2). The tool shows this formula with your own numbers substituted so you can verify the result.
Is Lighting Beam Spread Calculator free to use?+
Yes — it is completely free with no account, no sign-up and no usage limits. There is no watermark and no paywall.
Embed Lighting Beam Spread Calculator on your website
Want Lighting Beam Spread Calculatoron your own site? Paste this snippet into any HTML page — it's free, with no API key or sign-up. The tool loads in an iframe and keeps working exactly as it does here.
<iframe src="https://tooljolt.com/tools/lighting-beam-spread-calculator" width="100%" height="640" style="border:1px solid #e5e7eb;border-radius:12px;max-width:680px" title="Lighting Beam Spread Calculator — ToolJolt" loading="lazy"></iframe>Related Broadcast tools
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