Head to head
Samsung Galaxy S23vsSamsung Galaxy S21
The short answer
Choose the Galaxy S23 for peak brightness and Geekbench 6 CPU score. The Galaxy S21 wins no row by a gap you’d notice. The Galaxy S21 is £80 cheaper at UK RRP (£769 against £849). The Galaxy S21’s security updates ended in February 2026; the Galaxy S23 gets them until February 2028.
- Released
- 2023-02-17endoflife.date, retrieved 2026-08-20
- Price
- £849Samsung Newsroom UK — Galaxy S23 series, retrieved 2026-08-20
- Security updates until
- 2028-02-17endoflife.date — Samsung mobile, retrieved 2026-09-06
- Released
- 2021-01-29endoflife.date, retrieved 2026-08-20
- Price
- £769Samsung Newsroom UK — Galaxy S21 5G and S21+ 5G, retrieved 2026-08-20
- Security updates until
- 2026-02-21endoflife.date — Samsung mobile, retrieved 2026-09-06
2 wins for Galaxy S230 wins for Galaxy S211 gap borderline3 differences you won’t notice£80 apart at RRP
Verdict: Galaxy S23 ahead on 2 rows, Galaxy S21 on none
On the makers’ figures and the named third-party sources, the Galaxy S23 wins on peak brightness (1,750 nits from the maker against 1,300 nits from GSMArena) and Geekbench 6 (CPU, multi-core) (4,547 against 2,973, both from Geekbench Browser). One gap is borderline, a difference most people would not notice: claimed video playback (22 h against 20 h) for the Galaxy S23. The differences in weight, display size and battery capacity are below the thresholds you would notice. Both state the same refresh rate, storage (base), RAM, fast charging and wireless charging. The other 32 rows have no threshold or no direction to judge by, so nobody wins them.
True to scale
Outlines from each maker’s published dimensions, drawn to scale. Corner rounding is our drawing convention, not a measurement.
Specifications
A win is marked only where the figures can be ranked and the gap is one you could notice. A row the site has no threshold for says whether the two differ, and that it is not ranking them. = marks the same figure on both, ≠ not ranked a difference with no ranking. Every figure carries its source.
Body
Display
Platform
Memory
Camera
Battery
Connectivity
Benchmarks
8 attributes neither phone has a sourced figure for
Typical brightness · HDR peak brightness · OS versions supported · Google Mobile Services · Battery per charge · Battery lifespan · 3DMark Wild Life Extreme · Repairability (EU class). Rows appear as sources are cited — a gap in our data, not a statement about either phone.
Questions
Is the Galaxy S23 better than the Galaxy S21?
On the figures, the Galaxy S23 is ahead wherever there is a gap you’d notice: peak brightness, 1,750 nits (Samsung Newsroom UK) against 1,300 nits (GSMArena) and Geekbench 6 (CPU, multi-core), 4,547 against 2,973 (both Geekbench Browser). The Galaxy S21 wins no row by such a gap. That is a count of rows, not an overall score.
Which has the better battery?
The Galaxy S23 is ahead, narrowly: claimed video playback, 22 h against 20 h (both Samsung UK), a borderline gap most people would not notice. The Galaxy S21 is ahead on paper, but not by a gap you’d notice: battery capacity, 4,000 mAh against 3,900 mAh (both Samsung Newsroom UK).
Which is lighter?
The Galaxy S23 is lighter on paper, but not by a gap you’d notice: weight, 168 g against 169 g (both Samsung Newsroom UK).
Which has the brighter screen?
The Galaxy S23, by a gap you’d notice: peak brightness, 1,750 nits (Samsung Newsroom UK) against 1,300 nits (GSMArena).
Which gets updates for longer?
The Galaxy S21’s security updates ended in February 2026; the Galaxy S23 gets them until February 2028. Sources: dates from endoflife.date.
Which is cheaper?
The Galaxy S21 is £80 cheaper at UK RRP (£769 against £849). Prices from Galaxy S23: Samsung Newsroom UK; Galaxy S21: Samsung Newsroom UK.
Other comparisons
The pairs a buyer of either phone would also weigh. Any two phones in the catalogue can be compared from the chooser.