Some links on this page are affiliate links: if you buy through them we may earn a commission, at no extra cost to you.
Quick answer: Choose the Galaxy S21 for the smallest, lightest phone; the S21+ for a larger flat screen and more battery without paying for Ultra cameras; or the S21 Ultra for the highest-resolution display, long-range zoom and optional S Pen support. In 2026, all three are older phones, so condition, price and remaining software support matter as much as the original spec sheet.
At a glance
| Feature | Galaxy S21 | Galaxy S21+ | Galaxy S21 Ultra |
|---|---|---|---|
| Display | 6.2-inch flat FHD+ AMOLED, adaptive up to 120Hz | 6.7-inch flat FHD+ AMOLED, adaptive up to 120Hz | 6.8-inch curved WQHD+ AMOLED, adaptive 10–120Hz |
| Resolution | 2,400 × 1,080 | 2,400 × 1,080 | 3,200 × 1,440 |
| Weight | About 169–172g | About 200–202g | About 227–229g |
| Rear cameras | 12MP main, 12MP ultrawide, 64MP telephoto | Same basic arrangement as S21 | 108MP main, 12MP ultrawide, 10MP 3× and 10MP 10× telephoto |
| Front camera | 10MP | 10MP | 40MP |
| Battery capacity | 4,000mAh | 4,800mAh | 5,000mAh |
| RAM and storage | 8GB; 128GB or 256GB | 8GB; 128GB or 256GB | 12GB or 16GB; 128GB, 256GB or 512GB |
| UWB | Generally not included | Yes | Yes |
| S Pen | No | No | Compatible; sold separately |
| Charging | 25W wired, 15W wireless | 25W wired, 15W wireless | 25W wired, 15W wireless |
Specifications reflect Samsung’s published lineup; exact weights, radio bands, storage configurations and features can vary by country and model. See Samsung’s S21-series specification sheet and its S21 and S21+ details.
What the three phones share
These are members of the same 2021 flagship generation. All have 5G, a 120Hz-capable Dynamic AMOLED 2X screen, an ultrasonic in-display fingerprint reader, USB-C, IP68-rated water resistance, wireless charging, Wireless PowerShare and Samsung DeX. They launched with Android 11 and One UI 3.1. None has a microSD card slot, so storage cannot be expanded with a memory card.
Free tools Windows power users keep installed
One-click scans. No signup required.
All three also support features such as 8K video recording and Single Take, although the camera hardware behind those features is not the same. The standard S21 and S21+ share the same basic rear-camera setup; the Ultra adds substantially different sensors and two dedicated telephoto cameras.
#1 Best Overall
- The Samsung Galaxy S21 Ultra (Renewed) is a premium smartphone with a 6.8-inch AMOLED display, 120Hz refresh rate, and powerful camera system featuring a 108MP main lens and up to 100x zoom. It supports the S Pen, offers strong performance with 5G connectivity, and is ideal for users seeking flagship features at a better value.
Processor depends on market: some models use Qualcomm Snapdragon 888, while others use Samsung Exynos 2100. Do not assume performance, modem behavior, network compatibility or sustained gaming results are identical across regional versions. Check the exact model number and carrier bands before buying. The phones use similar software features, but performance under load also depends on chipset, heat, battery condition and software.
Size, materials and everyday handling
The S21 is the only one that feels compact by the standards of its generation. At roughly 71.2 × 151.7 × 7.9mm and about 170g, it is easier to pocket and use one-handed. It has a reinforced plastic rear panel rather than the glass backs used on the S21+ and Ultra; that construction helps keep weight down and is not automatically a durability disadvantage.
The S21+ is about 75.6 × 161.5 × 7.8mm and roughly 200g. It gives you much more screen and battery capacity while keeping a flat display. The Ultra is about 75.6 × 165.1 × 8.9mm and over 227g. Its camera housing and curved screen add to its bulk, so it is not simply a slightly larger S21+. Consider the weight if you use a car mount, carry your phone in a small pocket or hold it for long reading and gaming sessions.
Outdated Drivers Are Slowing You Down
One free scan finds every outdated or missing driver and matches the right update for your exact hardware.Free scan · exact hardware matchPC Slower Than It Used to Be?
A free scan shows the junk files, broken settings and background clutter dragging Windows down - then fixes them in one click.Free scan · Windows 10 & 11Samsung’s published dimensions and weights vary slightly by regional model, including radio configuration. Its Mobile Press specifications provide a useful reference.
Rank #2
- Item Package Dimension- 6.9299999929314L X 5.6299999942574W X 1.3399999986332H Inches
- Item Package Weight - 0.78925489796 Pounds
- Item Package Quantity - 1
- Product Type - Cellular Phone
Display: the S21+ is bigger, the Ultra is sharper
The S21 and S21+ have flat FHD+ panels: 6.2 inches on the S21 and 6.7 inches on the S21+. Both can refresh adaptively up to 120Hz. The S21+ is a size upgrade, not a resolution upgrade over the standard S21.
The Ultra has a 6.8-inch curved WQHD+ screen, with a resolution of 3,200 × 1,440 and an adaptive 10–120Hz refresh range. Its extra pixels can make fine text and detailed images look sharper, particularly when viewed close up. FHD+ is still adequate for most people and can require less rendering work. Samsung describes the Ultra’s adaptive display and resolution in its launch announcement.
The Ultra’s curved edges may look more distinctive, but they can also catch reflections, distort content near the edge or make accidental touches more likely. A damaged curved panel can be an expensive repair. On a used phone, inspect the whole display carefully for burn-in, dead pixels, tint and touch problems.
Cameras: the Ultra earns its premium with zoom flexibility
S21 and S21+: essentially the same camera hardware
In Samsung’s cited specifications, both have a 12MP stabilized main camera, a 12MP ultrawide and a 64MP telephoto camera, plus a 10MP selfie camera. Samsung describes the telephoto system as 3× hybrid optical zoom, with Space Zoom up to 30×. The S21+ is not a meaningful camera upgrade over the S21; its advantages are the larger screen, larger battery, glass back and UWB.
Rank #3
- The Galaxy S21 Ultra features a massive 6.8-inch Dynamic AMOLED 2X display with Quad HD+ resolution, HDR10+ support, and an adaptive 120Hz refresh rate that scales dynamically to deliver ultra-smooth visuals while conserving battery life.
S21 Ultra: four rear cameras with two telephotos
The Ultra combines a 108MP main camera, 12MP ultrawide, 10MP 3× optical telephoto and 10MP 10× optical telephoto, with laser autofocus and a 40MP front camera. The dedicated long-range lens makes it easier to frame distant subjects than on the other two phones. It is most useful for travel, wildlife, concerts, portraits and cropping photos taken in favorable light.
Do not read “100× Space Zoom” as a 100× optical lens. The Ultra’s optical telephoto cameras are 3× and 10×; 100× is the maximum computational/digital zoom mode, where detail can become soft or heavily processed. Samsung’s S21-series brochure distinguishes the dual optical zoom system from the maximum Space Zoom figure.
A 108MP label does not mean every photo is automatically better. At ordinary 1× in daylight, the gap may be smaller than the spec list implies. Image quality depends on lighting, motion, selected lens and software processing; the Ultra’s clearest advantage is its extra camera flexibility and cropping latitude. The 40MP selfie camera is not guaranteed to outperform the others in every lighting condition.
Battery and charging
Rated capacities are 4,000mAh for the S21, 4,800mAh for the S21+ and 5,000mAh for the Ultra. The S21 has the smallest reserve, while the S21+ offers a compelling screen-and-battery balance. The Ultra has the largest battery, but its high-resolution screen and more demanding hardware can offset some of that advantage. Capacity alone does not establish which lasts longest in a particular person’s use.
Rank #4
- Display: 6.2" AMOLED display with 120Hz refresh rate and 1300 nits brightness for vivid visuals and smooth scrolling.
- Camera: Rear dual camera system with 64MP main and 12MP ultrawide lenses for stunning photos and videos.
- Memory: 128GB internal storage and 8GB RAM for plenty of apps and files.
- Connectivity: 5G capable with support for GSM, CDMA, and Wi-Fi networks.
- Battery: 4000mAh battery provides all-day power for your daily needs.
On used devices, battery condition may matter more than the original capacity difference. A worn S21+ can have less practical endurance than a well-kept S21. Actual life varies with signal strength, display settings, apps, calls and workload; Samsung lists these kinds of factors in its specification materials.
All three support up to 25W wired charging and 15W wireless charging, as well as Wireless PowerShare. The Ultra does not charge faster than the less expensive models. Main launch-market boxes did not include a charger, so check what is included with a used or refurbished listing.
Performance, connectivity and storage
Each phone was a flagship at launch, but the regional Snapdragon 888 and Exynos 2100 versions can differ in sustained performance, image processing, battery behavior and modem support. For gaming, the S21 is easier to hold; the S21+ and Ultra have larger batteries and more room, but sustained frame rates depend on chipset version, heat, settings and battery health.
The S21+ and Ultra include ultra-wideband (UWB); the standard S21 generally does not. UWB can enable more precise nearby-device or object-finding experiences with compatible devices, tags, vehicles and software in supported markets. It does not automatically improve ordinary GPS navigation, and both sides of a feature need compatible hardware and software.
Best Value
- The Galaxy S21 Ultra features a massive 6.8-inch Dynamic AMOLED 2X display with Quad HD+ resolution, HDR10+ support, and an adaptive 120Hz refresh rate that scales dynamically to deliver ultra-smooth visuals while conserving battery life.
The S21 and S21+ have 8GB of RAM and 128GB or 256GB storage options. The Ultra came with 12GB or 16GB RAM and up to 512GB storage. Because none accepts microSD, choose storage with care: 128GB can be restrictive if you record a lot of 8K video, install large games or keep extensive offline media.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.S Pen: an Ultra-only option, not a built-in Note pen
The S21 Ultra supports S Pen input, but the pen was an optional accessory and the phone has no integrated slot to store it. You may need a compatible case or holder. Pen features and Bluetooth-dependent remote controls vary by pen model, so verify compatibility if those functions matter. The Ultra can suit note-taking and sketching, but it does not reproduce every convenience of a phone with a built-in pen silo. See Samsung’s Ultra announcement for its original S Pen support details.
Software support: an important 2026 buying factor
Samsung announced that the S21 family was eligible for up to four generations of Android/One UI upgrades and up to five years of security updates under its expanded policy. “Up to” is not a promise that every carrier and regional model receives every update on the same schedule. By 2026, these are discontinued-generation devices with a shorter remaining support runway than newer Galaxy phones. Do not assume a specific final patch date without checking the exact model and market.
Quick wins for a faster PC:
Clear out junk files and repair common Windows errorsFree Scan →Fix the driver behind crashes, sound loss and screen glitchesFind Drivers →Samsung’s US S21 product page marks the phones sold out, while its support pages remain available for manuals, repairs and firmware information. Its Certified Re-Newed catalog has focused on newer generations rather than offering dependable S21-series stock. Inventory changes, but if warranty, a newer battery and a longer support horizon are priorities, compare an S21 deal with a newer refurbished Galaxy such as an S23 or S24. Samsung’s policy announcement, product page and support page are useful starting points.
Which Galaxy S21 should you buy?
- Choose the Galaxy S21 if you want the lightest, most manageable phone and find it meaningfully cheaper than the S21+. Its cameras are broadly the same as the S21+; the compromises are the smaller screen and battery, and lack of UWB in general.
- Choose the Galaxy S21+ if you want a large flat display and larger rated battery without paying for the Ultra’s cameras. It is often the most balanced choice when the used-price gap from the S21 is small.
- Choose the Galaxy S21 Ultra if you will actually use its 10× optical telephoto, sharper screen, extra RAM/storage options or S Pen support. Accept the weight, curved screen and higher repair exposure, and buy only at a price that reflects its age.
- Choose a newer Galaxy instead if you plan to keep the phone for years, need a longer support runway, or find an S23/S24-generation refurbished model at a price close to the S21 phone you want.
Historical US launch MSRPs were about $799.99 for the S21, $999.99 for the S21+ and $1,199.99 for the Ultra; those are January 2021 prices, not current used-market values. In 2026, compare the actual price for the exact storage, condition, carrier status, warranty and battery policy rather than using launch MSRP as a value benchmark.
Used-phone checklist
- Confirm the exact model number, country/carrier variant, storage size, 5G bands and whether it is carrier-locked.
- Check IMEI status and confirm the phone is not financed, blacklisted or reported lost.
- Inspect the display for burn-in, dead pixels, tint, cracks and touch dead zones.
- Test each rear and front camera, autofocus, speakers, microphones, USB-C port, wireless charging, NFC, fingerprint reader and vibration motor.
- Ask about battery condition and test performance under ordinary load; remember that rated capacity does not reveal current health.
- Verify that any advertised S Pen, holder case, charger or other accessory is actually included.
- Do not treat an old IP68 rating as a guarantee after years of use or repairs. Samsung’s rating is water resistance under specified test conditions, not a promise that a used phone is waterproof.
- Confirm storage before purchase: none of the three has a microSD slot.
Samsung specified IP68 testing for submersion in up to 1.5 meters of fresh water for up to 30 minutes under controlled conditions; wear, damage or prior repair can change a used phone’s resistance. See its Ultra announcement for the stated test qualification.
Quick Recap
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
The Tool Desk
Outbyte Driver Updater FREEFix the driver behind crashes, sound loss and screen glitchesFind Drivers →Outbyte PC Repair FREERepair Windows errors before they cause bigger problemsFix Now →
