Samsung Galaxy S23 Ultra vs Samsung Galaxy S21 Ultra: SAR comparison

The Samsung Galaxy S21 Ultra lists the lower head sar, cellular only (us): 0.77 W/kg vs 0.98 W/kg for the Samsung Galaxy S23 Ultra (21% lower). Reported SAR values in W/kg; lower is shaded green and higher red within each row, for comparison only.

Open in interactive SAR Compare Samsung Galaxy S23 Ultra details Samsung Galaxy S21 Ultra details

Side-by-side SAR values

Samsung Galaxy S23 Ultra vs Samsung Galaxy S21 Ultra reported SAR and specs
Measurement	Samsung Galaxy S23 Ultra	Samsung Galaxy S21 Ultra
Head SAR, cellular only (US)	0.98 W/kg	0.77 W/kg
Body SAR, cellular only (US)	1.10 W/kg	1.02 W/kg
Head SAR, Wi-Fi + cellular (US)	1.59 W/kg	1.17 W/kg
Body SAR, Wi-Fi + cellular (US)	1.59 W/kg	1.57 W/kg
Hotspot SAR, cellular only (US)	1.20 W/kg	1.16 W/kg
Hotspot SAR, Wi-Fi + cellular (US)	1.54 W/kg	1.59 W/kg
Head SAR (EU, 10 g)	n/a	0.71 W/kg
Body SAR (EU, 10 g)	n/a	1.58 W/kg
Display: Type	Dynamic AMOLED 2X, 120Hz, HDR10+, 1200 nits (HBM), 1750 nits (peak)	Dynamic AMOLED 2X, 120Hz, HDR10+, 1500 nits (peak)
Display: Size	6.8 inches, 114.7 cm2 (~89.9% screen-to-body ratio)	6.8 inches, 112.1 cm2 (~89.8% screen-to-body ratio)
Display: Resolution	1440 x 3088 pixels (~500 ppi density)	1440 x 3200 pixels, 20:9 ratio (~515 ppi density)
Display: Protection	Corning Gorilla Glass Victus 2	Corning Gorilla Glass Victus
Hardware: Operating System	Android 13, One UI 5.1	Android 11, One UI 3.1
Hardware: Chipset	Qualcomm SM8550-AC Snapdragon 8 Gen 2 (4 nm)	Exynos 2100 (5 nm) - InternationalQualcomm SM8350 Snapdragon 888 5G (5 nm) - USA/China
Hardware: CPU	Octa-core (1x3.36 GHz Cortex-X3 & 2x2.8 GHz Cortex-A715 & 2x2.8 GHz Cortex-A710 & 3x2.0 GHz Cortex-A510)	Octa-core (1x2.9 GHz Cortex-X1 & 3x2.80 GHz Cortex-A78 & 4x2.2 GHz Cortex-A55) - InternationalOcta-core (1x2.84 GHz Kryo 680 & 3x2.42 GHz Kryo 680 & 4x1.80 GHz Kryo 680) - USA/China
Hardware: GPU	Adreno 740	Mali-G78 MP14 - InternationalAdreno 660 - USA/China
Battery: Type	Li-Ion 5000 mAh, non-removable	Li-Ion 5000 mAh, non-removable
Battery: Battery Test	Endurance rating 126h	Endurance rating 114h
Battery: Charging	45W wired, PD3.0, 65% in 30 min (advertised) 15W wireless (Qi/PMA) 4.5W reverse wireless	Fast charging 25W USB Power Delivery 3.0 Fast Qi/PMA wireless charging 15W Reverse wireless charging 4.5W
Design: Type	Bar	Bar
Design: Dimensions	163.4 x 78.1 x 8.9 mm (6.43 x 3.07 x 0.35 in)	165.1 x 75.6 x 8.9 mm (6.5 x 2.98 x 0.35 in)
Design: Weight	234 g (8.25 oz)	227 g (Sub6), 229 g (mmWave) (8.01 oz)
Design: Colors	Phantom Black, Green, Cream, Lavender, Graphite, Sky Blue, Lime, Red, BMW M Edition	Phantom Black, Phantom Silver, Phantom Titanium, Phantom Navy, Phantom Brown, Navy

Colors make differences within the same measurement easy to see. They do not label a phone safe or unsafe. US values use 1 g of tissue and the 1.6 W/kg limit; EU values use 10 g and 2 W/kg, so don't mix them. What SAR tells you.

Questions and answers

Which has lower head SAR, the Samsung Galaxy S23 Ultra or the Samsung Galaxy S21 Ultra?

The Samsung Galaxy S21 Ultra lists the lower head sar, cellular only (us): 0.77 W/kg vs 0.98 W/kg for the Samsung Galaxy S23 Ultra (21% lower). Values are reported maximums from FCC filings as listed in the RF Safe dataset, in W/kg averaged over 1 gram of tissue.

Which has lower body SAR, the Samsung Galaxy S23 Ultra or the Samsung Galaxy S21 Ultra?

The Samsung Galaxy S21 Ultra lists the lower body sar, cellular only (us): 1.02 W/kg vs 1.10 W/kg for the Samsung Galaxy S23 Ultra (7% lower). Values are reported maximums from FCC filings as listed in the RF Safe dataset, in W/kg averaged over 1 gram of tissue.

Which has lower hotspot SAR (Wi-Fi + cellular), the Samsung Galaxy S23 Ultra or the Samsung Galaxy S21 Ultra?

The Samsung Galaxy S23 Ultra lists the lower hotspot sar, wi-fi + cellular (us): 1.54 W/kg vs 1.59 W/kg for the Samsung Galaxy S21 Ultra (3% lower). Values are reported maximums from FCC filings as listed in the RF Safe dataset, in W/kg averaged over 1 gram of tissue.

What is the highest reported SAR value for each phone?

Across the six US measurements, the Samsung Galaxy S23 Ultra's highest listed value is 1.59 W/kg and the Samsung Galaxy S21 Ultra's is 1.59 W/kg. The FCC limit for the head and body is 1.6 W/kg averaged over 1 gram. Wi-Fi + cellular values are simultaneous-transmission sums and are evaluated differently, so read each row on its own.

Does a lower SAR mean a phone is safer?

No. SAR is a lab compliance measurement taken at maximum power. Everyday exposure depends on signal strength, distance from the body and which radios are active. Use SAR to compare phones, not as a health score.

Where do these numbers come from?

From the RF Safe SAR dataset, compiled from FCC equipment authorization filings (FCC ID A3LSMS918B and A3LSMG998U). Nothing on this page is estimated.

More comparisons

All phone-vs-phone pages · SAR rankings · Research library

Compare any two phones

First phoneSecond phone

Opens a ready-made comparison page when there is one, otherwise the interactive SAR Compare app.