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2K vs 4K security camera: what changes
Updated
4K has about 2.25 times the pixels of 2K, which helps when you zoom in on a face or a plate in daylight. With our assumed bitrates it also fills a memory card twice as fast and needs a stronger upload. For most homes, a 2K camera mounted closer to the door tells you more than a 4K camera mounted far away.
The pixel math
| Name | Frame size | Pixels |
|---|---|---|
| 1080p | 1920 x 1080 | about 2.1 million |
| 2K (the WYZE listing calls 2560 x 1440 "2.5K") | 2560 x 1440 | about 3.7 million |
| 4K | 3840 x 2160 | about 8.3 million |
Makers use "2K" loosely, so read the frame size on the listing if it is shown.
What it does to storage
We assume 1 Mbps for 1080p, 2 Mbps for 2K and 4 Mbps for 4K. Real cameras vary with the scene and settings, and Tapo's FAQ says the same about its own recording-time estimates. On those numbers, here is how long a 128 GB card lasts with nonstop recording.
- 1080p11.9 days
- 2K5.9 days
- 4K3 days
Motion clips go much further. At 30 clips a day of 20 seconds, a 32 GB card holds about 427 days at 1080p, 213 days at 2K and 107 days at 4K. Try your own numbers in the storage calculator.
When 4K helps
- A wide view that has to cover a whole yard, where you will zoom in later.
- Daylight scenes, where the sensor has plenty of light to work with.
- A wired camera on strong WiFi or a cable, with a large card or a recorder.
When it does not
- At night. Low light limits detail more than pixel count does. See how night vision works.
- On weak WiFi. More pixels need more upload. Reolink's WiFi page says 5GHz is faster but shorter range and may drop when the signal is weak, while 2.4GHz is slower but steadier over distance.
- On a battery camera. Bigger clips take longer to send, which keeps the camera awake longer.
Where our picks land
None of our six picks is 4K. The WYZE Cam v4 lists 2560 x 1440 and records nonstop to a card. Caveat: at that size a 128 GB card holds about 5.9 days of nonstop video on our math, so go bigger if you travel. The REOLINK Argus PT lists a 5MP sensor and dual-band WiFi. Caveat: it records motion events, not nonstop video. The eufy SoloCam S220 is 2K with 8 GB built in. Caveat: you cannot add a card, per what we saw on the listing. Compare all six in the roundup.
Privacy and the law: Aim cameras at your own property. Keep neighbors' windows, yards and other private areas out of the frame. Rules on recording audio differ by state, so check yours before you leave the microphone on. This is general information, not legal advice.