💾 Security Camera Storage Calculator
Enter your number of cameras, video bitrate (based on resolution), and how many days of footage you want to keep, to see the storage you need.
The bitrate and retention arithmetic
Bitrate is bits per second, so a day of one camera is its bitrate times 86,400 seconds, divided by 8 for bytes:
GB = cameras × bitrate(Mbps) × 86,400 × days / 8 / 1000
4 × 4 × 86,400 × 30 / 8 / 1000 = 5,184 GB = 5.18 TBThe division is by 1000, not 1024, matching how drive makers count - a 6 TB drive really does hold that 5.18 TB. Per camera per day, the four presets are:
| Preset | Bitrate | Per camera per day |
|---|---|---|
| 480p | 2 Mbps | 21.6 GB |
| 1080p | 4 Mbps | 43.2 GB |
| 1440p | 8 Mbps | 86.4 GB |
| 4K | 12 Mbps | 129.6 GB |
What moves the answer most
active hours / 24 to
estimate it, and remember pre-roll buffers and a busy street push the duty cycle
far above what a quiet back garden produces.- Codec. These presets are H.264 figures. H.265 gives similar quality at roughly half the bitrate, so a 4K camera in H.265 lands nearer 6 Mbps than 12.
- Variable bitrate. The number is an average. Rain, moving foliage and infrared noise at night all add detail, pushing a stream past its nominal figure for hours.
- Overhead. Add 15-20% for filesystem overhead and headroom, and remember a RAID 1 mirror doubles the raw capacity you must buy.
Frequently asked questions
How much storage do 4 cameras need for 30 days?
At 1080p and 4 Mbps recording continuously, 5.18 TB - so a 6 TB drive. The same four cameras at 4K need 15.55 TB, which is a 20 TB drive once you allow headroom.
How much space does motion-only recording save?
Usually 90-95%, an order of magnitude. A camera recording 5% of each day stores about 2.2 GB a day at 1080p rather than 43.2 GB, though the saving depends entirely on how often your scene triggers.
Does H.265 halve my storage need?
Close to it at the same visual quality, though the gain is smallest on simple, static scenes. Check the recorder decodes H.265 for playback and that your phone app does too, or you trade disk space for stuttering review.