Storage for 8 cameras for 30 days
By Devin Chua · Data checked by Owen Nakamura · Updated Eight cameras recording 30 days need about 30 TB at 4K H.265 (with overhead), or roughly 8 TB at 1080p H.265, recording 24/7. That points to a 4–6 bay NAS with large WD Purple or SkyHawk drives in RAID 5. The calculator below sizes the exact drives and cost for your bitrate.
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Size it exactly
Pre-filled for this question — change any input to model your own setup.
25.3 TB of footage over 30 days, +20% overhead = 30.4 TB
The worked example
Eight 4K H.265 cameras at ~10 Mbps each write about 105 GB per camera per day — roughly 845 GB a day for all eight. Over 30 days that is about 25 TB of footage, and adding ~20% overhead for the filesystem and indexes brings it to about 30 TB of usable storage. At 1080p H.265 the same eight cameras need only about 8 TB, because a 1080p stream is a quarter of a 4K one.
To hold 30 TB usable in RAID 5, you need the array's capacity minus one drive to reach 30 TB — for example five 10 TB drives (40 TB raw, ~32 TB usable) or four 12 TB drives. The calculator picks a real in-stock surveillance-drive configuration and a NAS with enough bays.
Cutting the 8-camera bill
Thirty terabytes of surveillance drives is a real cost, so the honest levers matter: H.265 over H.264 halves it; 1080p instead of 4K on cameras that do not need the detail cuts it to a quarter; motion-only recording helps on quiet scenes; and a shorter retention window scales linearly. Decide retention first, then let the calculator size it — and always with surveillance-rated drives, never desktop ones, for the 24/7 eight-stream write load.
Frequently asked questions
How much storage do I need for 8 security cameras?
For 30 days at 4K H.265, about 30 TB usable; at 1080p H.265, about 8 TB. It scales with retention (linearly), resolution and codec. The calculator gives your exact figure and the drives to buy.
What NAS do I need for 8 cameras?
A 4–6 bay NAS with surveillance drives, sized so its RAID-usable capacity covers your footage — around 30 TB usable for 4K at 30 days. Any surveillance-capable NAS works; the calculator recommends a specific model with enough bays.
How many hard drives for 8 cameras at 30 days?
For ~30 TB usable in RAID 5, roughly four to five large surveillance drives (10–12 TB each). Fewer, larger drives beat many small ones on power and bays. The calculator picks a live in-stock configuration for you.
Can I reduce storage for 8 cameras?
Yes — use H.265 (halves it), record 1080p where 4K is not needed (quarters it), enable motion-only on quiet scenes, or shorten retention. Each is honest and additive; the calculator shows the effect live.
Read more
Devin Chua works out which drives, RAM and NVMe cache fit which NAS model at nasdrives.ca, and what the RAID choice means for usable capacity, checked against what is in stock on Amazon.ca.
Data checked by Owen Nakamura, Technical editor (data checking)