How Much HDD Storage Do You Need for 6MP & 8MP Security Cameras? (1 Week, 2 Weeks, and 1 Month)
When setting up a CCTV system, one of the most common questions is how much hard drive storage you’ll need for continuous recording. This guide breaks down storage requirements for 2, 4, and 6 cameras in 6MP and 8MP resolutions—for 1 week, 2 weeks, and 1 month of recording.
Key Assumptions for Calculations
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H.265 video compression (modern standard for efficiency)
-
25 fps frame rate
- Continuous 24/7 recording
- Medium motion activity
-
Bitrate:
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6MP camera ≈ 4 Mbps
-
8MP camera ≈ 6 Mbps
Storage Formula
Storage (in TB) = (Bitrate × Cameras × Time in seconds) ÷ (8 × 1024³)
Bitrate in Mbps
Time = Days × 24 × 3600
Storage Needs for 6MP Cameras
| Cameras |
1 Week (TB) |
2 Weeks (TB) |
1 Month (TB) |
| 2 x 6MP |
0.61 TB |
1.22 TB |
2.61 TB |
| 4 x 6MP |
1.22 TB |
2.44 TB |
5.22 TB |
| 6 x 6MP |
1.83 TB |
3.66 TB |
7.83 TB |
Storage Needs for 8MP Cameras
| Cameras |
1 Week (TB) |
2 Weeks (TB) |
1 Month (TB) |
| 2 x 8MP |
0.92 TB |
1.84 TB |
3.92 TB |
| 4 x 8MP |
1.84 TB |
3.68 TB |
7.84 TB |
| 6 x 8MP |
2.76 TB |
5.52 TB |
11.76 TB |
Key Takeaways
-
8MP cameras need ~50% more storage than 6MP cameras.
- For most home setups (2–4 cameras), a 4TB HDD is enough for around 2 weeks of 6MP recording.
- If you need 1 month of footage for 6+ cameras, you’ll want 8TB or more.
- Always leave 10–20% free space on your NVR for system stability.
Pro Tips
-
Motion recording can reduce storage use by up to 70%.
-
Lower frame rates (15fps instead of 25fps) save space without a big quality loss.
- Always use a Surveillance-grade HDD (e.g., WD Purple, Seagate SkyHawk) for durability.
Note: Storage recommendations in this guide may vary depending on traffic levels, motion activity, lighting conditions, and other environmental factors.
