Lux Meter: Light Meter, PPFD

Lux Meter is a fast, simple light meter that uses your phone's ambient light sensor to measure illuminance in real time. Use it as a lux meter for rooms and desks, a plant light meter for houseplants and grow lights, or a quick light meter for photography — no account, no clutter, just the number you need. 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 that tells you when the reading has settled. Switch between lux and foot-candle (fc) at any time. 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 — handy 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, so you can decide how high to hang a lamp or how long to run it. LIGHT METER FOR PHOTOGRAPHY Check and compare lighting on your set, find even light across a subject, and log readings for repeatable results from one shoot to the next. ROOM & HOME LIGHTING Use the lux meter to measure desk, office, kitchen and room brightness and set up comfortable lighting for work, reading and study. Compare a spot before and after changing a bulb to see what really improved. 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 and grow lights • 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 meter • Optional camera color mode — estimated color temperature (K) • Light and dark themes, 50+ languages • No account, works offline for core measuring MORE TOOLS • Room heatmap — walk a grid and see where the light actually falls, with uniformity (min/avg); readings stay in memory only • Circadian light — an estimate of melanopic EDI from lux and the colour temperature you choose, with targets for day, evening and night; wellbeing information, not medical advice • Workplace check — compare a task area against EN 12464-1 maintained illuminance as a self-check, not a formal lighting survey • 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 WHO IT'S FOR Plant owners checking a new spot, indoor growers tuning a grow light, photographers balancing a scene, and anyone who wants to know whether a room is bright enough. If you have been looking for a light meter app that stays out of the way, this is it. ABOUT ACCURACY (please read) A phone light sensor measures ambient light but is not a calibrated professional lux meter; readings vary by device and by where the sensor sits. PPFD and DLI are estimates converted from lux. 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.