A calm light meter for real-world readings.
Lux Light Meter is a free, honest lux meter for iPhone and iPad — lux, photo exposure, and plant light in one focused instrument.
Why Lux Light Meter?
One instrument for ambient light, camera exposure, and grow-light checks — without clutter or inflated claims.
Honest readings
Camera-based lux and foot-candle estimates with clear accuracy notes and optional calibration against a reference meter.
Three modes, one app
Switch between ambient meter, photography exposure (aperture, shutter, manual), and plant PPFD / DLI guidance.
Free to measure
All measurement features stay free. Lux Pro adds history, trends, multi-point averaging, iCloud sync, and CSV export.
Features
Lux, fc, and color temperature
Real-time lux and foot-candle readings with color temperature (K), a responsive light meter, and Hold to lock a value.
Photography exposure
Aperture priority, shutter priority, and manual modes with EV₁₀₀; lock a reading and linked values update at the same EV.
Plant light guidance
Convert five common grow-light types to PPFD, estimate DLI from duration, and compare against 18 plant targets.
Indoor illuminance standards
23 built-in reference levels — office 300–500 lux, living room, kitchen, and more — for quick context.
Accuracy you can calibrate
Plain-language precision notes plus manual offset calibration when you have a reference light meter.
Logs, trends, and export (Pro)
Save readings, view trends, average multiple points, sync privately via iCloud, and export CSV with Lux Pro.
FAQ
Frequently asked questions about Lux Light Meter.
How accurate is the lux reading?
Lux Light Meter estimates ambient light from the device camera. It is useful for comparisons and everyday checks, but it is not a certified professional instrument. You can improve consistency with the built-in calibration offset against a reference meter.
Do I need to pay to measure light?
No. All measurement modes — lux, exposure, and plant light — are free. Lux Pro is optional and adds history beyond 20 entries, live trends, multi-point averaging, private iCloud sync, and CSV export.
What happens to the camera image?
The camera is used only to estimate light levels. Frames are processed in memory and discarded immediately. Lux Light Meter does not save or upload camera pictures.
Does it work on iPad?
Yes. Lux Light Meter runs on iPhone and iPad with the same measurement modes and layout adapted to each screen size.
How do I contact support?
Email support@luxlightmeter.andyrgb.com or visit the Support page on this site.
Ready to measure light with Lux Light Meter?
Free lux, exposure, and plant-light readings — coming soon to the App Store.