4K dash cams record four times the pixels of 1080p, which can make a number plate readable that would otherwise be a blur. But resolution isn't the whole story, and 4K costs you memory-card space. Here's how to decide.
Published 11 October 2026 · Last updated 11 October 2026
Why number plates matter
If you send footage to the police, they need the other vehicle's registration — and they say they can't enhance footage, so if the plate isn't readable in the original it probably won't be read at all. More pixels help, especially at a distance or when zooming in on a still.
But resolution alone doesn't guarantee it. Lens quality, processing, camera angle and the bitrate (how much data the camera saves per second) all matter. A heavily compressed 4K file can show less useful detail than a well-encoded lower-resolution one — check reviews and sample footage, not just the headline number.
What 4K costs in storage
Here's one maker's own figures. BlackVue's manual for the DR970X (4K front at 30fps) gives these recording times on a 128GB card:
| Quality setting | Front only | Front + rear (Full HD) |
|---|---|---|
| Extreme (25 + 10 Mbps) | 10 hr | 7 hr 20 min |
| Highest (12 + 10 Mbps) | 20 hr 40 min | 10 hr 40 min |
| High (10 + 8 Mbps) | 24 hr | 13 hr 20 min |
| Normal (8 + 6 Mbps) | 30 hr 40 min | 17 hr 20 min |
- At its top setting that's roughly 12.8GB an hour of front footage (our calculation from BlackVue's figures).
- Dash cams loop-record, overwriting the oldest files, so a bigger card mainly means a longer window before old footage is lost. Event files from crashes or a button press are protected from overwriting.
Use an endurance memory card
Constant recording wears cards out. Nextbase and VIOFO both recommend U3-rated cards designed for dash cam or CCTV use, and suggest formatting regularly (Nextbase says every 3–4 weeks). SanDisk rates its High Endurance cards in hours of recording — for example 10,000 hours for 128GB — and notes the totals are lower for 4K video.
So, is 4K worth it?
If you mainly want evidence for insurance after a collision, a good 1440p camera is often enough. If you want the best chance of reading plates on moving traffic — for police reports, say — 4K with a decent bitrate is worth paying for, as long as you buy a big enough endurance card. Browse our 4K dash cams.
Sources
Checked 11 October 2026. Rules change — follow the links for the current wording.