How Many Days Does a Camera Record? — Storage Made Simple

The worst surprise after an incident: the recorder has already overwritten the very day you need. When its disk fills up, a recorder (NVR) deletes the oldest footage and keeps recording over it. That’s why how many days video is kept should be decided up front — before installation.

What storage size depends on

• Number of cameras — each camera records its own stream, and the volumes add up;
• Resolution — with the same settings, a 4K camera’s stream is significantly larger than a 2MP camera’s;
• Bitrate — how many megabits per second a camera “uses”; the higher it is, the better the image and the more space it takes;
• Codec — H.265 stores the same image quality in less space than H.264;
• Recording mode — continuous 24/7 recording or recording on motion only;
• The scene — a busy hall, trees in the wind or night-time “noise” all increase the stream size.

The formula in a nutshell

Storage ≈ bitrate × recording hours per day × days × number of cameras.

The exact figure is different for every site, so instead of calculating by hand, use our CCTV calculator — it shows an approximate disk size based on the number of cameras, resolution and days.

💡 How many days is enough? Ask yourself: how long might it take to notice an incident? Theft or a cash discrepancy often surfaces only after several days — a two- or three-day archive won’t help then.

Saving space without losing quality

• Turn on H.265 (or the manufacturer’s “smart” codec) if your recorder supports it;
• In areas where nothing happens at night, use motion-based recording;
• Don’t give every camera maximum resolution — entrances and cash desks need detail, corridors need less;
• Choose surveillance-grade disks for the recorder — they’re designed for 24/7 recording.

Check reality

One or two weeks after installation, check on the recorder what the oldest available recording is. If it’s shorter than planned, adjusting the bitrate or recording mode is often enough.