A smartphone's DAS: what this figure means and where to find it

SAR is one of the few pieces of information that phone retailers are required to display in France. Many of our customers ask us what it means and whether it should be taken into account. Here is the essential information, without alarmism or downplaying its importance.

What is SAR?

SAR (specific absorption rate) measures the amount of radio wave energy absorbed by the body when using a phone. It is expressed in watts per kilogram (W/kg). It is measured in a laboratory, with the phone transmitting at its maximum power: it is therefore a worst-case value, rarely reached in everyday use.

The three SAR ratings

  • Head SAR: phone held to the ear during a call.
  • Trunk SAR: phone carried close to the body, for example in a jacket pocket.
  • Limb SAR: phone held in the hand or in a trouser pocket.

Legal limits

In Europe, a phone can only be sold if its SAR remains below 2 W/kg for the head and trunk, and below 4 W/kg for the limbs. In France, the ANFR (National Frequency Agency) takes phones from shops to check these values and publishes its results. All phones sold legally therefore comply with these thresholds.

Should you choose your phone based on its SAR?

A lower SAR means lower maximum exposure under test conditions. If this criterion matters to you, compare models against each other: the difference can be significant from one phone to another. But your actual exposure depends mainly on how you use your phone, as shown by the tips below.

Where can you find a phone's SAR?

  • In the phone's settings or user manual (legal or regulatory information section).
  • On the manufacturer's website.
  • On the ANFR website, which publishes the results of its checks.

Five simple steps to reduce exposure

  1. Use the hands-free kit or speakerphone for long calls.
  2. Preferably make calls when the network signal is strong: with fewer bars, the phone transmits at a higher power.
  3. Avoid making calls in the car or on public transport, where the phone constantly switches between antennas.
  4. Do not keep the phone against you at night: place it at a distance from the bed.
  5. For children and teenagers, prefer text messages and the hands-free kit.

Choosing your next smartphone

SAR is one criterion among others, along with the battery, screen, camera, and update support. Our guide to choosing a new smartphone reviews them. Then browse our Samsung Galaxy, Xiaomi, Google Pixel, iPhone, or our new tablets. Have a question? Our teams in our stores in Antibes, Pau, and Lescar are here to help.

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