How much NVR storage do security cameras need?
Storage depends mainly on total recording bitrate and retention time; camera count alone is not enough to size the drives.
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NVR Storage Calculator
How many terabytes do your cameras really need? Enter your camera count, resolution, frame rate, codec and how many days you want to keep — get the drive size before you buy the recorder.
Size your recorder
Quick reference (H.265, motion, 20 fps)
| System | 30 days | 60 days |
|---|---|---|
| 4 × 4MP | ≈ 2–3 TB | ≈ 4–6 TB |
| 8 × 4MP | ≈ 4–6 TB | ≈ 8–12 TB |
| 16 × 4MP | ≈ 8–12 TB | ≈ 16–24 TB |
| 8 × 4K | ≈ 8–12 TB | ≈ 16–24 TB |
Real usage varies with scene motion and camera settings — busy streets record far more than quiet hallways. Always leave 20–30% headroom, and use surveillance-rated drives (WD Purple / Seagate SkyHawk class).
Save storage
Three levers before a bigger drive
Switch to H.265
Cuts storage roughly in half versus H.264 with the same picture. Biggest single win if your gear supports it.
Motion-only where it fits
Quiet scenes drop 40–70%. Keep registers and entrances continuous; put back lots and hallways on motion.
Right-size the frame rate
15–20 fps is plenty for evidence. 30 fps looks smoother and eats 50% more disk than 20.
Answers
Storage questions
How much storage do security cameras need?
A typical 4MP camera on H.265 with motion recording uses roughly 15–30 GB/day. Eight cameras for 30 days ≈ 4–8 TB. Continuous recording or H.264 can double or triple that.
How much does H.265 save vs H.264?
Typically 40–50% at the same resolution and quality. If both cameras and recorder support H.265, turn it on.
Continuous or motion-only?
Motion-only for most cameras (40–70% savings), continuous for the critical few — registers, entrances, loading doors. Busy scenes save less on motion.
Do I need special hard drives?
Yes — surveillance-rated drives (WD Purple, Seagate SkyHawk class) are built for 24/7 writing. Desktop drives fail early in recorders.
Want the recorder sized for you?
Send Hi-Tech your camera count and retention needs — we'll spec the NVR, drives and network for Cleveland, Akron and Canton properties. Free review.
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