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What we think
The PerfectRec phone team Learn more
Updated January 10, 2024·
If camera quality is a significant factor in your decision, the OnePlus 9 offers slightly better overall camera quality, particularly it excels in still photo quality. However, if you value durability, the Samsung Galaxy S21 may be a better choice due to its slightly better build quality. Both phones have similar battery life, with the OnePlus 9 having a minutely longer battery life. The OnePlus 9 has a larger screen size, but if you prefer a more compact device, the Galaxy S21 is smaller and lighter. Both phones run on the Android operating system and are equipped with the same processor, offering similar performance. Keep in mind that the OnePlus 9 might be slightly more expensive, but it could be justified by its camera quality and larger screen. Give Feedback
this description is based on the product variant with some specs and product variant with some specs. At the time of writing, the variant with some specs cost some dollars and the variant with some specs cost some dollars.
Advantages of the OnePlus 9
- The OnePlus 9 has no clear advantages over the Samsung Galaxy S21.
Advantages of the Samsung Galaxy S21
- Good for taking photos
- Fair for recording videos
- Very good display quality
- Good performance
Key differences
Video Quality
5.9
6.6
The Samsung Galaxy S21 takes only fair videos, while the OnePlus 9 takes poor videos.
The Samsung Galaxy S21 delivers better video quality than the OnePlus 9 because it outperforms in crucial aspects such as video software experience, stabilization, dynamic range, low light performance, and microphone quality; whereas the OnePlus 9, although offering competent video capabilities, falls short in these same areas, leading to a more basic video output.
Screen Size
The OnePlus 9 has a screen size of 6.55 inches and the Samsung Galaxy S21 is 6.2 inches.
Cost
$399
$145
$0
$100
$200
$300
$400
$500
$600
The OnePlus 9 has a price of $399 and the Samsung Galaxy S21 costs $145.
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Key similarities
Overall Camera Quality
7.0
7.2
The Samsung Galaxy S21 and OnePlus 9 both have good overall cameras quality.
While both the OnePlus 9 and Samsung Galaxy S21 offer photo software features that enhance the image quality, the Samsung Galaxy S21's software provides a better overall experience. Moreover, the OnePlus 9's cameras are decent and versatile but the Galaxy S21 comes out ahead in selfie quality, which is very important, and offers slightly more advanced features that could improve camera performance in various scenarios.
Photo Quality
6.7
7.0
Although they have very similar scores, PerfectRec considers Samsung Galaxy S21 to have good photos, while the OnePlus 9 takes only fair photos.
The Samsung Galaxy S21 takes better overall photos than the OnePlus 9 due to a higher selfie score, enhanced photo software experience, and improved dynamic range and low light performance. Furthermore, the Galaxy S21's camera offering is more versatile with additional features like telephoto optical zoom, providing a range of photographic options not available on the OnePlus 9.
Battery
6.9 Hours
6.7 Hours
The OnePlus 9 has 6.9 hours of battery life. The Samsung Galaxy S21 has 6.7 hours of battery life.
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How the OnePlus 9 and the Samsung Galaxy S21 compare to other phones
Spec Comparison
 |  | |
| OnePlus 9 | Samsung Galaxy S21 |
GENERAL | |||
|---|---|---|---|
| Price | |||
$399 | $145 | ||
Brand | |||
Brand | OnePlus | Samsung | |
Operating System | |||
Operating System | Android | Android | |
Release Date | |||
Release Date | March 26, 2021 | January 29, 2021 | |
SCREEN | |||
|---|---|---|---|
Screen Size | |||
Screen Size | 6.55" | 6.2" | |
Resolution | |||
Resolution | 2400 x 1080 | 2400 x 1080 | |
Variable refresh rate | |||
Variable refresh rate | No | No | |
Pixels Per Inch | |||
Pixels Per Inch | 402 | 421 | |
Display Type | |||
Display Type | OLED | OLED | |
INTERNAL | |||
|---|---|---|---|
Processor | |||
Processor | SD888 | SD888 | |
Internal Storage | |||
Internal Storage | 128 GB | 128 GB | |
RAM | |||
RAM | 8 GB | 8 GB | |
CAMERA | |||
|---|---|---|---|
Overall Camera Quality Score | |||
Overall Camera Quality Score | 7/10 | 7.2/10 | |
Photos Score | |||
Photos Score | 6.8/10 | 7/10 | |
Videos Score | |||
Videos Score | 5.9/10 | 6.6/10 | |
Rear Cameras | |||
Rear Cameras | Main, Ultrawide | Main, Ultrawide, Telephoto | |
Main Camera | |||
Main Camera | 48 megapixels | 12 megapixels + OIS | |
BATTERY | |||
|---|---|---|---|
Battery Life | |||
Battery Life | 6.9 Hours | 6.7 Hours | |
Battery Capacity | |||
Battery Capacity | 4500 mAh | 4000 mAh | |
Wireless Charging | |||
Wireless Charging | Yes | Yes | |
Wireless charging Speed | |||
Wireless charging Speed | 15 W | 15 W | |
Reverse wireless charging | |||
Reverse wireless charging | No | Yes (4.5 watts) | |
PHYSICAL | |||
|---|---|---|---|
Size | |||
Size | 6.29" x 2.92" | 5.97" x 2.8" | |
Weight | |||
Weight | 6.77 oz | 5.96 oz | |
Back Material | |||
Back Material | Glass | Plastic | |
Stereo Speakers | |||
Stereo Speakers | No | No | |
CONNECTIVITY | |||
|---|---|---|---|
Dual SIM | |||
Dual SIM | No | Yes | |
Bluetooth Version | |||
Bluetooth Version | 5.2 | 5.0 | |
A2DP | |||
A2DP | Yes | Yes | |
WiFi Version | |||
WiFi Version | 6 | 6 | |
NFC | |||
NFC | Yes | Yes | |
US 5G Bands | |||
US 5G Bands | (SA/NSA/Sub6)1, 2, 3, 5, 7, 8, 20, 25, 28, 38, 40, 41, 48, 66, 71, 77, 78 | (SA/NSA/Sub6/mmWave)2, 5, 25, 41, 66, 71, 260, 261 (SA/NSA/Sub6)1, 3, 5, 7, 8, 20, 28, 38, 40, 41, 66, 77, 78 | |
OTHER FEATURES | |||
|---|---|---|---|
Biometric unlock | |||
Biometric unlock | Face unlock, Fingerprint sensor: Under Display | Face unlock, Fingerprint sensor: Under Display | |
Unlockable Bootloader | |||
Unlockable Bootloader | Yes | No | |
Color | |||
Color | Astral Black, Arctic Sky, Winter Mist | Phantom Gray, Phantom White, Phantom Violet, Phantom Pink | |
Stock Android | |||
Stock Android | No | No | |
SD Card | |||
SD Card | No | No | |
Shopping
OnePlus 9
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Dig into reviews and images
TechRadar
David Lumb | April 2021
"If you’re hunting for the best Android camera phone at this price, and one that doesn’t skimp on specs the OnePlus 9 is worth considering. Courtesy of a partnership with Hasselblad, the cameras offer better color correction, and both regular and ultra-wide photos look great. The OnePlus 9’s battery fully charges in under 30 minutes over a cable, and in 45 minutes using wireless charging. If you hate waiting for hours to charge your phone, you'll love the OnePlus 9."
Samsung Galaxy S21
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Dig into reviews and images
Android Central
Huseman Joe | February 2022
"The Galaxy S21 delivers the flagship Samsung experience in a phone that's much more pocketable (and affordable) than the top-end S21 Ultra.The triple-camera system is incredibly capable, Samsung's One UI 3.1 software is chock-full of features and settings to mess with, and I've not once missed having expandable storage."
Get a great deal on the OnePlus 9 or the Samsung Galaxy S21
About OnePlus
OnePlus, established in 2013, is a smartphone brand that first became known for providing flagship-like devices, at a fraction of the cost compared to more expensive Android competitors. OnePlus focuses on creating smartphones with powerful hardware at reasonable prices. They also bring hardware features normally not seen in other Android phones sold in the US, such as their ultra-fast “Warp Charge” and the beloved “Alert Slider”.
About Samsung
Samsung is one of the most recognizable names in the smartphone industry, standing as the undisputed best-selling brand of Android smartphones in the United States for many years now. Samsung is known for offering a variety of smartphones in all available price points, as well as for implementing cutting-edge technology and innovative features in their flagship devices, ones that often shape the market going forward. The company offers its own unique spin on Android, called One UI, which focuses on offering a multitude of features and is heavily customizable, according to user preference.
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Why trust us
This information was produced and vetted by the PerfectRec phones team. We are a product research and recommendation organization that meticulously reviews and evaluates the latest phone information and makes it digestible for you.
By the numbers
68
Phones evaluated
7,820
Phones stats compiled
8
Proprietary Phones ratings developed
125,100
Recommendations made
70,890
Consumer hours saved
About the phone team
Joe Golden, Ph.D
CEO and Phones Editor
Joe is an entrepreneur and lifelong electronics enthusiast with a Ph.D in Economics from the University of Michigan.
Jason Lew
Staff Expert & Software Engineer
Jason is a staff expert and software engineer that has been making laptop recommendations for 7 years and moderates one of the largest laptop subreddits.
Chandradeep Chowdhury
Staff Expert & Software Engineer
Chandradeep is a staff expert and software engineer and expert in televisions and monitors. He’s been making monitor recommendations for ten years.
Seth Peoples
Phones Expert
Seth is a US-based product expert focusing on smartphones and he is a moderator of one of the largest smartphone subreddits. His tailored recommendations have helped him earn over 87k comment karma, putting him in the top 1% of Redditors.
Efthimis Kotanidis
Phones Expert
Efthimis is a Greece-based product expert focusing on smartphones. He has been recommending phones for 4 years and his recommendations on Reddit have earned him over 35k karma.
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