What Size SD Card for a Dash Cam? A Simple Guide
For most dash cams, a 64GB or 128GB card is the sweet spot. It holds enough driving that an incident will not be overwritten before you save it, without paying for space you do not need. First check the largest card your camera supports, then size up if you run front and rear cameras, record in 4K or use parking mode.
How dash cams use the card
Dash cams record in a loop: when the card is full, the oldest clips are overwritten. Clips marked by a bump or the save button are protected. So the card size decides how far back you can go, not whether the camera keeps recording.
What fills a card faster
- Resolution: 4K uses far more space than 1080p. As a rough guide, 1080p uses about 5 to 8GB an hour per camera and 4K about 15 to 25GB, depending on the camera.
- Front and rear cameras: two cameras roughly double the space used.
- Parking mode: extra recording while parked fills the loop sooner.
Your camera's manual usually lists recording time for each card size, which is the most accurate figure.
The type of card matters more than the size
Dash cams write constantly, which wears ordinary cards out. Use a high-endurance card made for dash cams or security cameras. For 4K, choose a card rated for fast video writing, such as U3 or V30. A cheap card that fails quietly is worse than no camera, because you find out after the crash.
Looking after the card
- Format it in the camera every few weeks, not on a computer.
- Check now and then that clips are being saved.
- Replace it if the camera reports card errors.
Choosing and fitting the camera
Our dash cam buying guide for NZ covers the camera itself, and dash cam parking mode explains the battery side. We supply and fit dash cams with a suitable card: see dash cam installation.
Frequently asked questions
Is a 32GB card enough for a dash cam?
For a single 1080p camera with short trips, it can be. With two cameras, 4K or parking mode, it fills quickly, so 64GB or more is safer.
Can I use a 256GB card in my dash cam?
Only if the camera supports that size. Check the manual: many cameras have a maximum, and a larger card may not work.
Why does my dash cam keep saying card error?
The card may be worn out, the wrong type, or formatted on a computer. Format it in the camera, and replace it with a high-endurance card if errors continue.
How long does a dash cam SD card last?
It depends on the card and how much you drive. High-endurance cards last much longer than standard ones under constant recording.