Indoor Light Meter for Plants

Most common houseplants thrive in medium indirect light (500–2,000 lux). However, "low-light" plants can survive in as little as 50–250 lux, while sun-loving plants like cacti and succulents need 2,000–5,000+ lux of bright indirect or direct light. Always check your specific plant's requirements, as light needs vary widely by species.

Consumer-grade ambient light sensors (like those in smartphones and laptops) are typically accurate within ±10–20% of professional light meters. This is sufficient for general plant care purposes. For the most accurate reading, hold your device at the same height as your plant's leaves and point the sensor toward the light source. Avoid covering the sensor (usually near the front camera on phones).

Yes! Click the "Manual Mode" button to use preset scenarios or a slider to estimate light levels. Choose the scenario that best describes your plant's location—such as "Near Window" or "Dark Corner." While not as precise as a sensor reading, this gives you a solid starting point for understanding your plant's light conditions.

Lux is the metric unit for illuminance (lumens per square meter), while foot-candles (fc) is the imperial equivalent (lumens per square foot). The conversion is: 1 foot-candle ≈ 10.764 lux. This tool displays both units so you can use whichever you're comfortable with. Most plant care guides in the US use foot-candles, while international sources use lux.

Excellent low-light plants (tolerating 50–500 lux) include: Snake Plant (Sansevieria), ZZ Plant (Zamioculcas zamiifolia), Cast Iron Plant (Aspidistra elatior), Peace Lily (Spathiphyllum), Pothos (Epipremnum aureum), and Chinese Evergreen (Aglaonema). These plants evolved on forest floors and are adapted to thrive in shaded conditions.

The Ambient Light Sensor API is a web standard that allows browsers to access a device's physical light sensor. It returns illuminance in lux with decent precision. It's supported on Chrome (Android & desktop), Edge, and Opera. Safari and Firefox do not currently support this API. The sensor typically updates several times per second, providing real-time light readings. HTTPS is required for the API to function.

Leggy growth (long stems with few leaves) and pale foliage are classic signs of insufficient light. Plants stretch toward light sources when they're not getting enough. Use this tool to measure the actual light at your plant's position. If it's below the recommended range, consider moving the plant closer to a window, rotating it regularly, or supplementing with grow lights (LED grow lights typically provide 2,000–10,000+ lux at close range).