PPFD to Lux Calculator

Easily convert between illuminance (lux/fc) and PPFD (µmol/m²/s)

Illuminance measures the amount of light reaching a surface as perceived by humans. It is measured in lux (lumens/m²) or foot-candles (lumens/ft²). PPFD measures the amount of plant-usable light (PAR) your plant receives at a given moment. Since Illuminance and PPFD weight wavelengths differently, the conversion between them depends on the measured light source.

⚠️ Note: These conversion values are only rough guidelines and are based on theoretically ideal values. A lux meter doesn't even register most red and blue light because it's tuned to human vision — this leads to an erroneous conversion. For actual PAR measurements, download the Photone app to measure the accurate PPFD directly with your smartphone.

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Common PPFD to Lux Conversions

The table below shows illuminance (in lux) for common PPFD inputs across four common grow-light sources. For instance, 600 µmol/m²/s PPFD of sunlight equals roughly 33,300 lux, while the same 600 µmol/m²/s from a full-spectrum LED equals about 42,900 lux — the difference is driven by the source spectrum.

PPFD (µmol/m²/s)	Sun/Daylight	LED Full Spectrum	High Pressure Sodium (HPS)	Fluorescent
100	5,556	7,143	7,143	7,692
200	11,111	14,286	14,286	15,385
300	16,667	21,429	21,429	23,077
400	22,222	28,571	28,571	30,769
500	27,778	35,714	35,714	38,462
600	33,333	42,857	42,857	46,154
800	44,444	57,143	57,143	61,538
1,000	55,556	71,429	71,429	76,923
1,500	83,333	107,143	107,143	115,385

Formula: lux = PPFD ÷ light source conversion factor. Illuminance rounded to integer lux.

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PPFD to Lux Calculator

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Common PPFD to Lux Conversions

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