Key Takeaways
• Footage loops, it doesn't disappear: your dash cam records over the oldest unprotected clips once the card is full, so it never stops recording.
• Card size sets the window: a 64GB card holds roughly 4 to 8 hours of 1080p footage; a 128GB card roughly doubles that.
• Resolution and bitrate matter: 4K and high-bitrate settings fill a card far faster than 1080p.
• Two cameras halve your time: a front and rear setup writes two streams at once, so use a larger card.
• Protected clips are kept: the G-sensor locks collision footage so loop recording cannot overwrite it until you review it.
How long does dash cam footage last? There are really two answers. Ordinary footage lasts until the memory card fills up, at which point loop recording overwrites the oldest clips, typically a few hours to a day or more depending on your setup. Protected footage, such as a clip locked by the G-sensor after an impact, is kept until you review and delete it. As a rule of thumb, a 64GB card holds around 4 to 8 hours of 1080p video before it starts looping. The exact figure depends on your card size, resolution, bitrate and how many cameras you run. Browse our range of front and rear dash cams to find the right setup.
Dash Cam Recording Time by SD Card Size
These are approximate recording times for a single camera before loop recording begins. Actual times vary with bitrate, frame rate and compression (H.265 stores far more than older H.264).
| SD card size | 1080p Full HD | 4K Ultra HD |
|---|---|---|
| 32GB | around 2 to 4 hours | around 1 to 2 hours |
| 64GB | around 4 to 8 hours | around 2 to 4 hours |
| 128GB | around 8 to 16 hours | around 4 to 8 hours |
| 256GB | around 16 to 32 hours | around 8 to 16 hours |
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A front and rear (dual-channel) setup records two streams at once, so roughly halve the figures above. For a dual camera, a 128GB or 256GB high-endurance card is recommended.
How Loop Recording Works
Dash cams manage storage using loop recording. Instead of filling the card and stopping, the camera records continuously in short segments, usually one, three or five minutes each, which you can set in the menu. When the card is full, it overwrites the oldest unprotected segment to make room for new footage. The result is a "fit and forget" system: you can drive for weeks without touching the device, knowing your most recent journeys are always stored.
What Affects How Long Footage Lasts
Memory card capacity
The size of your microSD card is the main factor. Cards for dash cams typically run from 32GB to 256GB. A 32GB card suits a short daily commute, while drivers doing long shifts, such as taxi drivers or couriers, should fit the largest capacity their camera supports.
Video resolution and bitrate
Higher quality uses more space. A 4K camera captures enough detail to read distant number plates, but the files are large, so a 64GB card that holds several hours at 1080p may only manage a couple of hours at 4K. Bitrate and compression matter just as much: a camera using H.265 (HEVC) stores far more footage than one using older H.264 at the same resolution. Balance image quality against how much history you want to keep.
Number of cameras
Adding a rear or interior camera roughly halves your recording time, because each lens writes its own stream. The trade-off is worth it for the coverage: a front and rear system captures tailgaters, rear-end shunts and parking knocks. Explore our dash cams for single and dual-channel options.
How Dash Cams Protect Accident Footage
A common worry is that loop recording might erase vital evidence. It won't, thanks to a few safeguards.
The G-sensor
Every modern dash cam has a built-in G-sensor (accelerometer) that detects sudden changes in force. If you brake hard, swerve or suffer an impact, it locks the current clip into a write-protected folder that loop recording will never overwrite. Your footage stays safe until you extract it.
Manual locking and parking mode
You can also lock a clip manually using the camera's emergency button if you see an incident developing. Parking mode changes things too: while parked, the camera sits dormant and wakes only for motion or impacts, which saves huge amounts of space and lets a single card watch over your vehicle for days.
SD Card Lifespan and Maintenance
Although footage overwrites automatically, the card itself wears out. The constant read-write cycles of a dash cam put memory cards under real stress.
Use a high-endurance card
Do not reuse an old card from a phone or camera; standard cards corrupt quickly under continuous recording. Buy a high-endurance microSD card built for dash cams, which uses higher-grade flash designed for thousands of overwrite cycles and the temperature swings inside a car.
Format regularly
Even a good card needs maintenance. Over time, locking and deleting clips fragments the data and can cause stutters or dropped recording. Format the card every three to four weeks (through the camera menu or app) to keep it running cleanly. Review and back up any protected clips before you do.
Exporting and Archiving Footage
Once you have captured an important event, save it before the card fills or fails. Many cameras have built-in WiFi to transfer clips straight to your phone, which is ideal for settling a roadside dispute. Alternatively, remove the card and copy the original files to a computer, then back them up to cloud or an external drive so you always keep a clean copy.
Protect Every Journey
Understanding how your camera manages storage means you never lose evidence when it matters. Choose the right card capacity, balance your resolution, and keep the hardware maintained. To find the right camera and card for your driving, explore our front and rear dash cams or call our team on 0330 055 2777.
Frequently Asked Questions
How long does dash cam footage last before it is overwritten? Unprotected footage lasts until the SD card is full, then loop recording overwrites the oldest clips. This is typically a few hours to over a day, depending on card size, resolution and how many cameras you run.
How many hours does a 64GB dash cam card hold? Roughly 4 to 8 hours of 1080p footage from a single camera, or around 2 to 4 hours at 4K. A front and rear setup roughly halves that.
Does a dash cam delete old footage automatically? Yes. Loop recording automatically overwrites the oldest unprotected clips once the card is full, so the camera never stops recording. Protected clips are kept until you review them.
Does 4K reduce dash cam recording time? Yes. 4K files are much larger than 1080p, so a card holds noticeably fewer hours at 4K. Bitrate and compression (H.265 vs H.264) also make a big difference.
How long does parking mode footage last? Parking mode only records when motion or an impact is detected, so it uses far less space and can monitor a parked car for several days on a single card.
What size SD card is best for a dash cam? For a single 1080p camera, 64GB or 128GB is a good balance. For 4K or a front and rear setup, choose 128GB or 256GB. Always use a high-endurance card.
