A dash cam keeps recording by looping over old footage. The real limit is how much it can hold before that loop starts. Card size, video resolution, loop recording, and parking mode all affect that. This guide breaks it down and helps you choose the right card.
How does card size change recording time?
Card size is the biggest factor. A larger card stores more footage before the camera has to overwrite anything. Higher resolution fills the card faster, so 4K uses more space than 1080p. For most drivers, a mid-size or large card makes life easier.
Think of the card like a storage box. The bigger the box, the more clips it holds. Once it fills up, the camera starts using the oldest space again.
Resolution changes how fast that happens. A 4K file is much larger than a 1080p file, so the same card lasts for fewer hours at 4K.
Card speed matters too. A slow card may struggle with high-resolution recording and drop frames. Use one that meets the SD card speed classes from the SD Association. Most dash cam options in Sri Lanka also list the largest card they support. If you want more detail on resolution, see our guide to understanding dash cam specs.
How does loop recording keep it going?
Loop recording is what lets a dash cam record continuously. When the card fills up, the camera deletes the oldest clip and keeps going. You do not need to clear files by hand. Most cameras also save footage in short segments, which makes clips easier to find later.
Those short segments are useful. Each clip only runs for a few minutes, so the files stay easy to handle.
When the card is full, only the oldest clip goes. Newer clips stay in place until they age out. The camera keeps recording without stopping.
If something important happens, save it right away. Move it off the card before loop recording reaches it.
Parking mode and recording when the car is off
Parking mode records while the car is parked and switched off. It does not run all the time. Instead, it wakes up on motion or impact and saves a short clip. That uses much less space and power than constant recording. It also needs steady power, usually through hardwiring.
Recording all the time while parked would drain the battery fast. Parking mode avoids that by staying idle until something happens near the car.
Motion detection starts recording when someone or something moves close. Impact detection starts when the car gets a knock. Both save space because they only record the moments that matter.
Parking mode needs power even when the engine is off. A hardwire kit usually handles that. Our dash cam installation guide explains the setup.
Browse car dash cameras at Xclusive and check the supported card size before you buy.
FAQs
Can a dash cam record 24 hours?
A dash cam can keep recording through loop recording, which overwrites old footage. If you want it to record while parked and off, it needs parking mode and a steady power source. It keeps reusing the oldest clips, so it does not truly run out of space.
How many hours can a 128GB card record?
A large card can hold many hours before loop recording starts. The exact time drops at higher resolution because 4K files are larger than 1080p files. Card size and resolution together decide the total.
Can I leave my dashcam on 24/7?
Yes, if you use parking mode and a hardwired power source. Parking mode wakes only for motion or impact, so it saves space and battery. Without steady power, the camera stops when you turn off the engine.