How Much Hard Drive Storage Do I Need for CCTV?
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As a rough guide, a 4-camera 4MP system recording continuously needs about 2TB for two weeks or 4TB for around 30 days using H.265 compression. More cameras, higher resolution or longer retention all increase the storage you need.
Rough storage guide (continuous, H.265)
| System | ~30 days |
|---|---|
| 4 x 4MP cameras | 3 to 4TB |
| 4 x 8MP (4K) cameras | 4 to 6TB |
| 8 x 4MP cameras | 6 to 8TB |
| 8 x 8MP (4K) cameras | 8 to 12TB |
These are ballpark figures - actual use depends on scene activity, frame rate and bitrate.
Continuous vs motion recording
Recording only on motion can cut storage use dramatically - often by half or more for a quiet property - because the system isn't writing empty footage all day.
H.265 vs H.264
H.265 (and H.265+) roughly halves file sizes compared with older H.264 for the same quality. Use it if your cameras and NVR support it - most modern Hikvision and HiLook kits do.
Get an exact figure
Use our CCTV storage calculator to enter your exact cameras, resolution and days and get a precise drive size.
Use the right drive
Always fit a surveillance-rated hard drive, not a desktop one. Surveillance vs normal hard drives. Browse surveillance drives.
Frequently asked questions
How many days does a 2TB drive record?
Roughly two weeks for a 4-camera 4MP system on continuous H.265 recording - longer if you record on motion only. Use our storage calculator for an exact figure.
Does motion recording save space?
Yes - recording only when motion is detected can cut storage use by half or more on a quiet property.
What size hard drive for 8 cameras?
For 8 cameras at 4MP expect around 6 to 8TB for a month of continuous recording; 8 to 12TB at 8MP. Motion recording reduces this.