Lux Meter: Light Meter, PPFD

Lux Light Meter is a fast, accurate light meter and lux meter that uses your phone's ambient light sensor to measure illuminance in real time — for rooms, indoor plants and photography.

MEASURE LIGHT IN LUX

See the current light level in lux on a large, easy-to-read display, with minimum, average and maximum values and a stability indicator.

LIGHT METER FOR PLANTS (PPFD & DLI)

Create plant profiles with a target lux range and instantly see whether a spot is too dim, good, or too bright — perfect for monstera, ficus, succulents, herbs and seedlings on a windowsill or under a grow light. Switch to grow-light mode to get an estimated PPFD (PAR) and DLI based on your light source (sunlight, white LED, HPS, metal halide, fluorescent) and daily light hours.

LIGHT METER FOR PHOTOGRAPHY

Check and compare lighting on your set, find even light, and log readings for repeatable results.

ROOM & HOME LIGHTING

Measure desk, office and room brightness to set up comfortable, healthy lighting for work and study.

KEY FEATURES

• Live lux measurement (min / average / max + stability)

• Lux or foot-candle units

• Real-time light trend chart

• Estimated PPFD (PAR) and DLI for plants

• Plant, room and photo profiles with target ranges

• Measurement history with date, time and profile

• Export history to CSV to share or analyze

• Calibration (offset + multiplier) to match a reference

• Optional camera color mode — estimated color temperature

• Light and dark themes, 50+ languages

• No account, works offline for core measuring

MORE TOOLS

• Room heatmap — map a grid and see where the light actually falls, with uniformity

• Circadian light — melanopic EDI with targets for day, evening and night

• Workplace check — a task area against EN 12464-1 maintained illuminance

• Timed logging — a set interval, automatic stop, CSV export

• Profile trend — one profile's readings over time against its target range

• Compare two readings, share one as an image, add notes

• Quick targets and spoken readings, hands-free

• Home-screen widget, plus backup and restore to a file

ABOUT ACCURACY (please read)

A phone light sensor measures ambient light but is not a calibrated professional lux meter; readings vary by device. Camera color temperature is an estimate; true CRI needs dedicated spectral hardware. Use Lux Meter as a helpful guide, not a certified instrument.

PRIVACY

Measurements and profiles stay on your device. The camera, when used, only estimates color on-device — no photos are saved or uploaded.