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Keep The Guesswork Out of Grow Lighting

Measure PAR / PPFD, Lux, Kelvin:
All with an app

Grow Light Meter App

Go Pro:

Set up your plants’ lighting with a proper PAR light meter.

Photone is the light meter app that allows you to take all the light measurements relevant for your plants and for all widely used grow light technologies.


  • PAR / PPFD in µmol/m²/s

  • DLI in mol/m²/d

  • Illuminance in lux and foot-candle

  • Light temperature in Kelvin

Your Benefits

Built for Grow Lights

We actively develop, test, and optimize for the widely used grow lights in the market.

No Costly Equipment

Photone only requires your smartphone’s camera — nothing else.

Tailored to Plants

Measure PAR in µmol/m²/s and even calculate your plant’s DLI at the palm of your hand.

Proven Accuracy

Compared to various common hardware light meters or similar apps, Photone is repeatedly achieving the lowest average error rates in measuring grow light illuminance.

Average Error

31.7 %
Light Meters
1.8 %
iPhone 14


0.9 %
iPhone 11 Pro
1.5 %
iPad Pro 11"

More information on measurement accuracy and evaluation details on the above error rates can be found in our extensive light meter comparison.

View Comparison

Reviews and Mentions

Comparison to Apogee SQ-500 PAR Sensor


Comparison to Apogee MQ-500 PAR Meter

by HowWeedGrow

Comparison to Apogee MQ-500 PAR Meter

by Growing Answers

Comparison to Apogee SQ-120 Underwater PAR Sensor

by Recif_conde

User Reviews

out of 5
Titty lo mein – Sep 13, 2022
Impressively similar to quantum sensors
Tested the app against a 500$ hydrofarm quantum sensor and as long as your light diffuser is properly attached, your readings will be identical
by htdrjigghh356 – May 14, 2021
Great app!
My problem with my soup, was actually my lighting problem. I was able to mitigate my hot and cold spots. My average DLI across my garden is now around 40. Before I had spots as low as 14 and as high as 80, yikes! After adjusting the light I was also able to turn off 60 watts of LED lightning saving energy and my plants. Highly recommended app!
by Justin Gross – 26 Mar 2023
Handy App for your phone no need for extra equipment
best app of 2023. I've been Wondering if my plants have been getting proper light, come to find out my lights were more efficient than I had thought and I've been roasting my plants until now thank you tons ..
by Mariyan P – Apr 26, 2021
Matches Manufacturer PPFD at given height
Compared to what my manufacturer claims my lights PPFD is at 12” which is around 780 and this app came to about high 700s low 800s very happy with accuracy
by 4Dbox – Mar 10, 2021
Very useful in the indoor garden
It’s simple to use, has a pleasant interface, and the readings correlate to manufacturers PPFD output charts for my grow lights. Very useful for setting LED light heights. Make sure to construct the simple white paper diffuser as recommended by the developers . I wholeheartedly recommend this app.
by Crankdoctor – Feb 24, 2020
Helped so much.
I tried a couple apps and nobody had one for different lighting so this was a great step above. I purchased a new grow light and had it to low and to high for a week. Almost toasted my plants. I could only find around about how high I needed it on web. I seen this app and it could read led white and red together so I was on it! Needles to say it put me in the sweet spot and plants are loving light now thanks to this app. It’s a game changer. I’m sold!


Photone is available for iPhone, iPad, and Android Smartphones.
It's free.