# Flash Guide Number Calculator

> Flash guide number calculator: find the right aperture or flash power from guide number and distance for correct exposure. Free, private, runs in your browser.

- **Canonical URL:** https://boringtoolskit.com/flash-guide-number-calculator/
- **Category:** Photo & Video
- **Evidence level:** catalogue
- **Reviewed:** July 26, 2026
- **Last verified:** 2026-10-12
- **Privacy:** Inputs and results stay in this browser unless the page clearly labels an external request.

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