Photone - Grow Light Meter icon

Photone - Grow Light Meter v1.1.5

• In-app purchases

Photone - Grow Light Meter screenshot 0 Photone - Grow Light Meter screenshot 1 Photone - Grow Light Meter screenshot 2 Photone - Grow Light Meter screenshot 3 Photone - Grow Light Meter screenshot 4 Photone - Grow Light Meter screenshot 5 Photone - Grow Light Meter screenshot 6 Photone - Grow Light Meter screenshot 7 Photone - Grow Light Meter screenshot 8 Photone - Grow Light Meter screenshot 9 Photone - Grow Light Meter screenshot 10 Photone - Grow Light Meter screenshot 11 Photone - Grow Light Meter screenshot 12 Photone - Grow Light Meter screenshot 13 Photone - Grow Light Meter screenshot 14 Photone - Grow Light Meter screenshot 15 Photone - Grow Light Meter screenshot 16 Photone - Grow Light Meter screenshot 17 Photone - Grow Light Meter screenshot 18 Photone - Grow Light Meter screenshot 19 Photone - Grow Light Meter screenshot 20 Photone - Grow Light Meter screenshot 21 Photone - Grow Light Meter screenshot 22 Photone - Grow Light Meter screenshot 23

About this app

Developer Description

Keep The Guesswork Out of Grow Lighting: Measure PAR / PPFD for Plants

Take the guesswork out of plant lighting with Photone, the most accurate plant light meter app. Measure PAR, PPFD, DLI, lux, foot-candles, and color temperature (kelvin) directly with your phone or tablet.

To measure light with research-grade accuracy, Photone uses the most precise sensor in your device: the camera**. Its unique measurement algorithm works directly with the RAW camera sensor data to capture true light intensity. This allows Photone to rival professional handheld PAR meters in accuracy and go even further by helping you interpret the numbers with in-app guides, tools, and additional features.

MEASUREMENTS

⎷ Photosynthetically Active Radiation (PAR) as PPFD in µmol/m²/s
⎷ Daily Light Integral (DLI) in mol/m²/d
⎷ Illuminance in lux or foot-candles
⎷ Light color temperature in kelvin
⎷ Extended PAR (ePAR) including far-red light (ePPFD, eDLI) *

FEATURES

⎷ Industry-leading accuracy, comparable to professional PAR quantum sensors
⎷ Pre-calibrated for your specific device **
⎷ No ads
⎷ In-app guides
⎷ Light source selection for every type of grow light (LED, HPS, CMH, etc.) *
⎷ Average and peak readings *
⎷ Plant light calculator
⎷ Hands-free “read aloud” function *
⎷ Special underwater measurement mode *
⎷ Custom calibration option to align readings to another meter
⎷ Premium support for advanced grow questions *

* These features require an in-app purchase to fully unlock

DIFFUSER REQUIRED

Like every real light meter, Photone requires a diffuser to measure accurately**. A diffuser scatters incoming light evenly on the sensor and prevents hotspots. While it may sound complex, the solution is surprisingly easy. You have two options:

1) Easily build a diffuser yourself in less than a minute using standard printer paper. This is accurate enough for most use cases.

2) Get the dedicated Diffuser Accessory (free worldwide shipping) for best accuracy and convenience. More details on https://lightray.io/diffuser/.

** ENHANCED LIGHT MEASUREMENTS WITH THE CAMERA
Accurate light measurements with the camera require a default calibration, which is made available only for selected higher-quality devices. Check the full list of supported devices here: https://lightray.io/diffuser/compatibility/

On devices without default calibration, Photone automatically falls back to the built-in ambient light sensor (ALS). While the ALS works without an external diffuser, it is far less accurate than camera-based measurements. Learn more about the differences between the two sensor types here: https://growlightmeter.com/guides/different-light-intensity-sensors/

UPGRADE OPTIONS

Photone is free to download and use with all basic features without any ads or hidden costs. To unleash its full potential, Photone offers two types of upgrades:
→ Lifetime unlocks — one-time purchase, always restorable via your Google Account
→ Pro subscription — full access for as long as you subscribe, cancel anytime

Photone took more than 5 years of R&D to develop. Upgrading not only unlocks powerful features, but also supports future development and keeps the app ad-free for everyone. As a member of 1% for the Planet, we donate at least one percent of all revenue to environmental non-profits — so every purchase helps both your plants and the planet.

DOWNLOAD FOR FREE. TRUSTED BY MILLIONS.

Optimized for plant growers and indoor gardeners – whether you’re growing in a grow tent, greenhouse, hydroponics system, an aquarium, or are just looking for the best quantum meter app for your LED grow lights, Photone has got you covered.


Terms and Conditions: https://growlightmeter.com/terms/
Privacy Policy: https://growlightmeter.com/privacy/

What's New

This update fixes a bug introduced with version 1.1.4 that caused inaccurate measurements at low light levels on some devices. It also resolves an issue where the screen would lock during measurement.

In-app purchases

$4.49 - $74.99 per item

Version Information

Version
1.1.5
Downloads
100K+
Updated on
Dec 4, 2025
Released
Jul 26, 2021
Requires
Android 7.0

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Photone - Grow Light Meter users say on Google Play

★★★★★
Scott MacFarlane Scott MacFarlane

I ve had this app for a couple of years and it's exactly what you need when growing anything indoors its so simple to use and can't be matched in my opinion the results speak for them selves so try it you'll be impressed!

12 May 16, 2025
★★★★
moo kau moo kau

I've been using it on and off since beta. Now I see there are "pro" settings they want me to pay $75 to unlock. They also want to sell a diffuser for $40. Oh, but it's "on sale" for an "introducotry" price of $26, except it was introduced years ago. $100+ for a setup that uses my own phone hardware to extrapolate. It's a good tool, but if I want to "go pro," I'll save up the 5x for a pay once, dedicated hardware meter.

18 Apr 21, 2025
★★★
Andy Czubai Andy Czubai

Quite the variance readings between this app and my SF pro sensor. And the "paper filter" taped on the phone seems kinda hoakey. Still deciding.

0 Dec 11, 2025
★★
Maja Szerb Maja Szerb

Used to be ok... The only plus was the PAR meter, which option is not free anymore... :S Also you can't see what you're measuring in because you can't get rid of the diffuser info panel! ...so I just uninstalled it and will use another app which is more user friendly!!

1 Aug 7, 2025
Malcom Wind Malcom Wind

Too confusing to understand the readings and doesn’t tell you if is shade or full sun just a numberreading that stays wildly in flux. Pop ups to buy a diffuser or to buy premium services prevent you from using the app in any significant way and apparently you have to buy a diffuser to actually get any readings that are accurate so in general a fail from the start.

2 Oct 6, 2025

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