The Best Lux Meter App on iOS in 2021

I spent the time and money to test them all so you don’t have to

Dominik Maglia
8 min readMar 10, 2021

I tested all lux light meter apps that I found on the App Store. The test revealed that most of them are entirely useless as they miss their one single purpose: To measure accurately.

Luckily, there are some exceptions and one clear winner.
See the table below with all the measurement results sorted from best to worst:

All results ordered by average error

Apart from the large deviations in measurement accuracy, the over-all quality of those apps differs heavily as well. Some of them seem like an outright scam, others are just poorly made software, while a few are really well made and feel nice to use.


My recommendation is based on the following few factors, ordered by priority:

  1. Measurement accuracy
  2. Usability and user experience
  3. Stability and performance
  4. Maintenance, support, and App Store reviews

The one clear winner is the Light Meter LM-3000, which I can fully recommend on all levels:

It offers a free trial and I think when it comes to replacing a handheld light meter, the price is more than justified.

If a completely free app is desired and accuracy is not important to you, I can recommend the Luminos Meter:

Please mind that it has not been updated ever since its release, the user interface looks really clunky, and the App Store reviews are not that great.

Methodology for Testing

As for proper testing, a stable and controllable lighting environment is key. I therefore spent a bit of time assembling a test rig that allows exactly that.


I set up a test rig that houses a 120W LED Quantum Board equipped with warm-white 3000K LED chips within a light-proof photography box. The LED light is powered by an adjustable power supply that allows to set different brightness levels with great control and accuracy. In this test I varied the brightness from 200 Lux to 123'000 Lux and around doubled it with every step.

The whole test setup consisting of the high-power LED light, power supply, and light-proof box


A PeakTech® 5086 JIS C 1609:1993 Class A certified light meter was used for the reference measurements. If possible, all measurements were taken right at the center below the light. However, some of the apps use the back camera, where a simultaneous measurement and reading was not possible. So the camera was then pointed towards the center.


All apps were tested on an iPhone 11 running iOS 14.4 and with the most recent version available as per March 2021.

The Apps

I browsed the App Store and downloaded every app that claims to measure Lux that I could find. In the end, I ended up with 15 downloaded apps and over $30 spent.

All fifteen apps that were tested

Below you can find the detailed listing of all the tested apps and some comments from my side.


This app seems like a scam. There is a somewhat nice onboarding that shows how to use the app to measure light, but when you get past that it only prompts you to scan a QR code. No measurement was possible.

Light Meter App

On my phone (and on others’ based on the reviews) this app always crashed on launch. I wasn’t able to take a single measurement with it. I don’t recommend to spend any time on it.

Lux Camera — Light Meter & Measurement

This app has not been updated for the last 5 years, which is never a good sign. Using it is a bit of a hassle as well as it shows some very obtrusive advertising on every launch. Once you get past that, it is fairly easy to take an (inaccurate) measurement.

Nurus Light Wellnes

As far as I understand, this app is provided by an interior design company and also allows for other measurements. It is free, has no advertising, and the user interface is pretty easy-to-use.

Light Meter LM-3000

This app comes with a nice and simple skeuomorphic user interface and a lot of attention to detail such as the onboarding. At the beginning, it requires you to build a diffuser using a strip of paper and once this is attached it does everything you need from a light meter and is very accurate.


Honestly, I don’t understand how one can develop such a terrible user interface in 2021. It is very hard to press the buttons, animations are slow, icons are pixellated, and worst of all: It doesn’t store the settings after a restart so you have to mess with those tiny buttons whenever using the app. Based on its price tag of $4 I expected a really accurate and professional tool, which it unfortunately isn’t.

Lux Meter — light measurement tool for measuring lumens, foot candles, lx and light temperatur‪eLux Meter

The last update on this app was done in 2015 so it seems unmaintained. It claims to be calibrated with a professional high-precision illuminance meter which did not reflect in my measurements.

Luminous Meter

This app is a bit clunky, but it also allows to do many things such as logging light measurements. Additionally, it is free, has not much advertising and works somewhat decently, depending on the brightness level. There is no version history so it still seems to be the initial release from

Lux Light Meter Pro

This app is very obtrusive in trying to upsell you to a paid subscription ($1 a month) or on a one-time purchase ($5) on every launch. Once you get past that, the main user interface is a bit hard to operate but OK once you figure out how. Unfortunately, it measures way too low.

Light Meter — lux and foot candle measurement too‪l‬

This app is released by the same developer as the “Lux Light Meter Pro” but costs $2 whereas the other one is free?! It also seems unmaintained since 2016 but still looks and measures exactly the same as the other app.

Light Meter — measure luminosity in lux, fc, lume‪n

This app is an interesting find: It looks and measures very similar to those two light meter apps by Marina Pollyanskaya but again is costing $2 — I wonder what the story behind those related apps is. But still: They measure way too low and cannot be used for light measurement. This app is also unmaintained since 2017.

Light Lux Meter

Cost $4 and last update is 3 years old. Developer published many apps but no clear specialty between them. Mostly generic utility apps.

This developer seems to be publishing many generic apps in the utility sector. The app raised high expectations with the $4 price tag but is unfortunately inaccurate as well. I cannot back their claim of “the best Light Meter app for iPhone” if factors such as measurement accuracy, usability, performance and upkeep are considered.

Galactica Luxmeter

This app is on the market since 2013 with its last update in 2017 which can clearly be seen: An outdated user interface that is not adapted to new iPhones. It is also dangerously inaccurate and measures way too high.

Lux Light Meter FREE

This app feels like a weekend project or a programming assignment that is monetized with advertising, but the developer also offers a paid version that then removes the ads. As for measurement accuracy, it could really be worse but fluctuates a lot so I would have an issue in trusting the measurement.


I had high hopes in the Luxi app as it seems pretty widespread in the photography community. I even purchased the $20 Luxi Clip diffuser attachment as the app recommends doing so.

The $20 Luxi Clip diffuser attachment for the Luxi app

Unfortunately, this app has the highest error rate in this test and I do not recommend using it to measure any light levels at all.

Closing Thought

For me, this has been an interesting test: Many apps claiming to do the same, yet they are completely different. I hope that this article is comprehensible and makes sense. If you think that my measurements are flawed: Please challenge me! Recreate a stable test setup and measure those apps against an accurate and reliable reference. I’d be pleased to see your results.

Thank you for reading!



Dominik Maglia

I am a design and technology nerd and love to create value by making the complex simple and accessible!