Smartphone (cellular uplink)
Handsets transmit up to about 200 mW (23 dBm) on cellular uplink and are used against the head, so exposure is governed by SAR — 1.6 W/kg over 1 g in the U.S., 2 W/kg over 10 g under ICNIRP — not by power density.
Last verified 12 August 2026.
Also searched as: mobile phone, cell phone, phone radiation
- Category
- radiofrequency
- Emission bands
- Cellular uplink (700 MHz–3.8 GHz); Wi-Fi / Bluetooth
- Environments
- home, workplace, vehicle, school
- Transmit power
- 0.2 W EIRPRegulatory value — legally enforceable — 23 dBm is the typical LTE/5G-NR power class maximum for handsets. Phones transmit far below this when signal is strong, and at the maximum when signal is weak.sources: fcc-2-1093
- Duty cycle
- Uplink power is adaptive: one or two bars of signal can mean orders of magnitude more transmit power than full bars for the same call.
Field strength by distance
- 1 cm
- 0.2–1.6 W/kgManufacturer figure — Reported head SAR for handsets sold in the U.S. must not exceed 1.6 W/kg over 1 g at maximum transmit power. Per-model values are in the FCC equipment authorization filing for the device's FCC ID.sources: fcc-2-1093, fcc-eas
- 30 cm
- 177,000 µW/m²Computed estimate — S = EIRP / (4πd²) with EIRP = 0.2 W, d = 0.3 m — Far-field approximation only; at 30 cm the phone is roughly one wavelength away at 1 GHz.sources: fcc-2-1093
- 1 m
- 15,900 µW/m²Computed estimate — S = EIRP / (4πd²) with EIRP = 0.2 W, d = 1 msources: fcc-2-1093
Mitigations, most effective first
- Use speakerphone or wired earphones instead of holding the phone to the head.
- Moving the transmitter from 1 cm to 30 cm removes almost all of the local SAR.
- Make calls where signal is strong, and avoid calling from lifts, basements or moving vehicles.
- Adaptive power control means good signal directly reduces transmit power.
- Prefer Wi-Fi calling and data over cellular when available; keep the phone off the body when transmitting.
- Wi-Fi uplink power is typically an order of magnitude below cellular uplink maximum.
- Look up your model's SAR in the FCC equipment authorization database rather than relying on third-party lists.
- Gives the tested value for the exact hardware revision.
Measure with
- Broadband RF power-density meter
Related records
- FCC SAR limit for phones and portable devices
1.6 W/kg averaged over any 1 gram of tissue — the number quoted on U.S. phone SAR sheets — plus 0.08 W/kg whole-body.
Exposure limits
- ICNIRP 2020 local SAR basic restriction (head and torso)
2 W/kg averaged over 10 grams of tissue for the general public — a different averaging mass than the FCC's 1 g, which is why SAR numbers are not directly comparable between regions.
Exposure limits
- IARC classification of radiofrequency fields as Group 2B (2011)
IARC classified radiofrequency electromagnetic fields as possibly carcinogenic to humans (Group 2B) based on limited evidence for glioma and acoustic neuroma from heavy mobile phone use.
Research record
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.
- fcc-eas Equipment Authorization Search (FCC ID lookup, includes SAR test reports) — Federal Communications Commission. government, link checked 2026-08-12.
- who-emf-rf Radiation: Electromagnetic fields (questions and answers) — World Health Organization. government, 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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