How Much CCTV Storage Do You Need?

CCTV storage decides how long footage remains available before it is overwritten. If the hard drive is too small, the system may work perfectly but still lose the footage you need before anyone checks it.

Storage needs depend on camera count, resolution, frame rate, bitrate, compression, recording schedule, motion settings, and retention requirement. Camera count alone is not enough.

Bitrate is the amount of data a camera records each second. Higher resolution and higher frame rates usually increase bitrate. Compression reduces the storage needed for the same footage.

Common compression formats include H.264, H.264+, H.265, and H.265+. H.265-based systems are generally more efficient than older H.264 systems, but the real result depends on camera settings and scene activity.

If four 8MP cameras record continuously at around 3 Mbps each using efficient compression, the total bitrate is about 12 Mbps. Divide by 8 to convert to roughly 1.5 MB per second.

Over a full day that is about 129.6 GB. A 2 TB drive is roughly 2048 GB, so the approximate retention would be 2048 divided by 129.6, giving about 15.8 days before footage is overwritten.

Some sites only need a few days of footage. Others need several weeks because incidents may not be discovered immediately. Shops, hospitality venues, industrial sites, farms, and care settings may all have different needs.

Retention should be long enough to be useful but not excessive. Data protection considerations also matter when recording people.