What size SD card does a 4K front and rear dash cam need?
A 256GB card keeps a full 8-hour driving day from a 4K front and rear dash cam at a typical 42 Mbps; 64GB covers a 2-hour commute. Buy a high-endurance card and check your camera's maximum supported size.
SANDISK 256GB High Endurance microSD Card + Adapter
256GB / high endurance
The 256GB size that holds a full driving day at this setting, in a high-endurance grade built for loop recording.
How big a card for how many hours?
A 4K front and rear camera writes about 18.9GB per hour at a typical 42 Mbps. Each extra 1080p channel adds about 10 Mbps, which is why the rear camera costs you roughly 24 percent of the loop.
| Hours to keep | Space needed | Card to buy |
|---|---|---|
| 1 h | 20 GB | 32GB |
| 2 h | 41 GB | 64GB |
| 4 h | 81 GB | 128GB |
| 8 h | 163 GB | 256GB |
| 12 h | 244 GB | 256GB |
| 24 h | 488 GB | 512GB |
How long does each card size last at this setting?
| Card | Loop length |
|---|---|
| 16GB | 47 min |
| 32GB | 1 h 34 min |
| 64GB | 3 h 9 min |
| 128GB | 6 h 18 min |
| 256GB | 12 h 36 min |
| 512GB | 25 h 12 min |
Cards and 4K front and rear cameras
Check the camera's maximum supported card size before buying.
(5 Yrs Free Data Recovery) (Dash Cam) GIGASTONE 64GB Micro SD Card, TLC High Endurance...64GB / high enduranceUnder $25Check price on Amazon
SANDISK 128GB High Endurance Video microSDXC Card with Adapter for dash cam and home...128GB / high enduranceUnder $50Check price on Amazon
Integral 128GB High Endurance microSD Card for CCTV, Dash Cam & Security Cameras, 4K...128GB / high enduranceUnder $50Check price on Amazon
VIOFO 64GB Industrial Grade High Endurance microSDXC Card for Dash Cam64GB / high enduranceUnder $50Check price on Amazon
Dash Cam Front and Rear 4K+1080P, 5GHz WiFi, App Control, with 64GB Card4K / 2 channel / Wi-FiUnder $50Check price on Amazon
ROVE R2-4K Dual PRO Dash Cam Front and Rear, 4K+2K Dash Camera for Cars4K / 2 channelUnder $250Check price on Amazon
BlackVue Elite 10, 4K+4K Dash Cam Front and Rear, STARVIS 2, Free 64GB Card4K / 2 channelUnder $1,000Check price on Amazon
Frequently asked questions
Is 128GB enough for a 4K front and rear dash cam?
128GB holds about 6 h 18 min at this setting. That covers daily commuting, but a long road-trip day or heavy parking-mode use can overwrite footage before you check it, so 256GB is the safer choice if your camera supports it.
Do I need a high-endurance SD card?
Yes. A dash cam rewrites its whole card every few hours, and ordinary cards are not rated for that. High-endurance cards are built for continuous video and handle windshield heat better. A worn-out card often keeps recording but writes corrupt files, so format it in the camera every few weeks and replace it at the first recording error.
What speed class does a dash cam card need?
Even a three-channel 4K camera writes only a few megabytes per second, so a U3 or V30 card is enough. This setup writes about 5.3 MB per second. Endurance, not speed, is what decides how long a card lasts.
