SAR (specific absorption rate)
Watts absorbed per kilogram of tissue, the dosimetric basis of phone compliance testing — 1.6 W/kg over 1 g in the U.S., 2 W/kg over 10 g under ICNIRP.
measurement
Last verified 12 August 2026.
- Category
- measurement
Definition
SAR quantifies RF power deposition in tissue. It is measured in a liquid-filled phantom with the device transmitting at maximum power in its worst-case configuration, which is why a device's SAR is a compliance figure rather than a description of everyday exposure. Because the U.S. averages over 1 gram and ICNIRP over 10 grams, published SAR values for the same phone differ between regions and must not be compared directly.
Sources
- fcc-2-1093 47 CFR § 2.1093 — Radiofrequency radiation exposure evaluation: portable devices — U.S. Government Publishing Office (eCFR). regulation, link checked 2026-08-12.
- icnirp-2020 Guidelines for Limiting Exposure to Electromagnetic Fields (100 kHz to 300 GHz) — International Commission on Non-Ionizing Radiation Protection, 2020. guideline, link checked 2026-08-12.
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