I've researched in the Internet but can't find any conclusive answer.

When will your phone emit more radiation, downloading 1 Mb of data from a cell network (3G, 4G) or downloading the same amount of data using WiFi? What is likely to consume more energy?

  • 2
    $\begingroup$ Your question would benefit from clarification. 1. There are two questions here one about radiated power, the other about energy consumption. While correlated, subject to architecture, the correlation may not be strong and can differ widely from model to model. 2. it would be helpful if you clarify what you mean by 'radiation'. Mobile phones do not emit ionizing radiation, often the generally accepted usage of the term. They do of course emit in the radio (and infrared) band of the electromagnetic spectrum but then so does a clock radio. $\endgroup$
    – pHred
    May 25, 2019 at 11:06
  • 2
    $\begingroup$ You speak of both "downloading" and "emits". A phone will emit radiation while sending data, and that radiation will be stronger the closer one is to the phone, but it emits very little while receiving data. The WiFi point or the cell tower do not send directional signals; they broadcast in all directions. When your phone is receiving data, it receives as much radiation from the WiFi or tower as everything and everyone in the same range from the transmitter. Compare it to the light emitted by a ceiling light bulb, with the book you are reading being the equivalent of the phone. $\endgroup$ May 25, 2019 at 12:46
  • $\begingroup$ @pHred, I mean any electromagnetic radiation. $\endgroup$ May 26, 2019 at 21:05
  • $\begingroup$ @Ray, in this case I think it would be interesting to know the data when it uploads 1 Mb of data. $\endgroup$ May 26, 2019 at 21:06

1 Answer 1


So, after a little googling around.

Cellphones typically transmit on 3/4 G at between 0.3 and 3 W - subject to tower location & interference. The out put power is managed by the cell tower.

Mobile phone wifi is typically 15mW.

If we assume min output for 3/4 G at 300 mW (0.3 W) this is, at best, 20 times greater than wifi at 15 mW.

On that basis I would expect wifi to be the more energy efficient medium.

However protocol efficiency also plays a part. The simplest crude measure of this is probably to time how long each channel takes to recieve the same block of data and scale the power usage accordingly. Note that subject to your data plan upload / download speeds will usually differ & so there may be different results for each direction.


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