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Lux meter vs phone

Updated: 22 October 2026

You already have a light-meter app that shows lux. You are deciding whether that figure is enough for a room or a shelf, or whether a handheld is the better buy. This lux meter vs phone page turns on what each sensor is for. The phone's chip dims the screen. A handheld is a cell you can cap, place, and aim, and in this set it is still not a certified field meter. The [lux meter comparison](/hub/measuring-equipment/lux-meter) lists the twelve models. Peter F. used the listings, the UK reviews, and published app comparisons. A qualifying purchase can earn a commission at no extra cost to you.

You already have a light-meter app that shows lux. You are deciding whether that figure is enough for a room or a shelf, or whether a handheld is the better buy.

Our top picks

TopTes TopTes TS-710

Best overall

TopTes TopTes TS-710
8.2/10about £29.99
View offer
Dr.meter Dr.meter 1010BS split

Best value

Dr.meter Dr.meter 1010BS split
6.1/10about £18.99
View offer
URCERI URCERI handheld

Alternative

URCERI URCERI handheld
6.8/10about £29.99
View offer
On this page
  1. 1.What the phone is actually sensing
  2. 2.What the comparisons found
  3. 3.When a handheld from this set is the better buy
  4. 4.When neither is enough

What the phone is actually sensing

The phone uses an ambient-light sensor to keep the screen readable, not to report illuminance on a desk. A field photometer follows the eye and accepts light from the side in a defined way, often called cosine correction. The Institution of Lighting Professionals describes that head. A phone does not claim it. Neither do these twelve handhelds. You can lay the handheld's cell on the plane, remove a cap, and step back. You cannot park the phone's sensor without parking the phone in its own shadow. An app that prints lux has borrowed the unit.

What the comparisons found

DIAL compared lux-meter apps with a measuring instrument. The phones lacked the eye match and the cosine correction of a photometer. The same app on similar phones did not agree, and a calibration at one level did not hold at another. The app's number belongs to that phone, that app, and that brightness. It does not travel as the lux on a UK chart. Cerovac and colleagues tested nine phones and 14 apps around 300–1,000 lux and found them unsuitable for occupational decisions. The study is not a UK lab. An URCERI reviewer said the meter agreed with another light meter where apps did not. This page will not say phones are 60% out.
TopTes TopTes TS-710

Testsieger

TopTes TopTes TS-710
8.2/10about £29.99
View offer

When a handheld from this set is the better buy

Buy a handheld if you will compare the same spots again and you want a cell you can cap and place. Keep the phone if you only want a hint and you will not quote the number. The moment you write "320 lux", the phone is the wrong instrument. The handheld here is still a consumer meter. The 1010BS separates sensor and display. No listing shows a UKAS certificate or cosine correction. £12.99 to £32.97 does not buy a survey meter. How you take that reading is how to use a lux meter.

When neither is enough

A workplace check and any number for an employer sit outside both. These handhelds do not state cosine correction or a certificate. Regulation 8 requires suitable lighting. It does not authorise a screenshot. Phone and pocket meter can both rank two spots under one white lamp. Neither gives photosynthetic photon flux under a red-and-blue LED. If you need micromoles, that limit is on lux meter for plants. For the dimmer corner you may check again, buy the handheld.

Common questions

Is a light-meter app the same as a lux meter?
No. The app shows a lux unit from the sensor that dims the screen. A lux meter has a cell you place on the surface. Neither the phone nor these twelve listings is a cosine-corrected, certified photometer. Sharing the word lux on the display does not make them the same instrument.
Why do two phones disagree?
The sensor, the glass, the app, and the angle all differ. DIAL found the same app disagreeing on similar phones, and a one-level calibration that failed at another level. Tilt your own phone and the number moves because the aim moved. Two handsets are not two copies of one meter, so averaging them does not create a reference.
Can I calibrate the app once and trust it?
Not across a house. Published checks found a correction at one brightness that did not hold at another, and you will not have their reference meter. A slider in the app does not turn the phone into something you can set beside a UK lux chart. Rechecking it against a window once does not fix the next lamp.
Is the app good enough to compare two corners?
As a hint, yes, if you hold the phone the same way and you only care which side looks brighter. It is not enough if you will write the number or match a chart. A handheld placed on each corner, in lux, with you out of the light, is the better tool for that second job. It is still not a survey.
Should I still buy a £15 meter?
Buy one if you will repeat the check and you want a cell you can cap. Around £17 to £19 you are looking at V·Resourcing or the Dr.meter 1010BS. The two V·Resourcing colours share one review pool. The 1010BS uses manual ranges and stops at 100,000 lux. Do not buy either as a certificate. Do not skip a meter only because the app already prints a digit.
Will the app tell me if my grow light is enough?
No. Lux from a phone or from these meters is the wrong quantity for enough, especially under red and blue. You can see which position under one lamp is brighter to the eye. You cannot turn that into a growth target. A PPFD app is a different product, and this page does not review one.
Can I use the app for a workplace check?
No. Work on occupational illuminance finds the phone unsuitable for that decision. These handhelds are not the substitute, because they carry neither a certificate nor a cosine statement. If someone else must rely on the figure, use a competent person and a meter specified for the job.

Related pages

Lux meter buying guide

Lux meter

Best lux meter: aiming pick, room pick, best value

Lux meter for plants: compare spots under one lamp

How to use a lux meter for a reading you can repeat

Sources

Public UK sources from the research digest, last checked on 19 October 2026. Shelf prices and star lines are the amazon.co.uk figures captured with these twelve listings. The price bands are this set, not a market average.

  1. Workplace (Health, Safety and Welfare) Regulations 1992, regulation 8 (retrieved 19 October 2026)
  2. HSE HSG38: Lighting at work (retrieved 19 October 2026)
  3. HSE: Lighting (retrieved 19 October 2026)
  4. HSE L24: Workplace health, safety and welfare (retrieved 19 October 2026)
  5. ILP Guidance Note 7: Choosing a photometer or illuminance meter (retrieved 19 October 2026)
  6. LIA TS23 (retrieved 19 October 2026)
  7. CIBSE LG7: Lighting for offices (2023) (retrieved 19 October 2026)
  8. Michigan State University: Light into perspective (retrieved 19 October 2026)