Browser-only calculation · no form data sentCCTV Recording Storage Calculator
Estimate storage for continuous or scheduled recording using the average bitrate per camera.
Formula
Cameras × Mbps ÷ 8 × recording seconds × retention days × headroom, converted from bytes to decimal TB and binary TiB.
Motion recording: Savings depend on the scene, sensitivity, and activity. Use the 24/7 result as an upper comparison, then correct it with a week of measured usage.
Why TB and TiB differ
Drive vendors define 1 TB as 10¹² bytes. Binary units use 2⁴⁰ bytes per TiB, so the same byte count appears smaller when expressed in TiB.
Scenario comparison
Results compare the recording hours you enter with a 24/7 continuous upper case. Motion-active hours vary by location, season, and sensitivity, so do not treat the apparent saving as guaranteed.
Worked examples
| Setup | Example inputs | Check before buying |
|---|
| Two entrance cameras | 2 cameras · 2 Mbps · 12 h · 30 days | Include night noise and busy periods |
| Four home perimeter cameras | 4 cameras · 4 Mbps · 24 h · 30 days | About 5.70 TB as the continuous upper case |
| Eight-camera small shop | 8 cameras · 4 Mbps · 16 h · 45 days | Check after-hours policy and NVR capacity limits |
Next step
Read how codecs, frame rate, and motion recording affect retention.
Formula and units
Camera count × average Mbps per camera × recording hours × retention days is converted from bits to bytes, then the selected headroom is added. Decimal TB uses 10¹² bytes while TiB uses 2⁴⁰ bytes, so the two displayed numbers describe the same bytes in different units.
Worked examples
Two entrance cameras
Enter 2 cameras, 2 Mbps each, 12 hours per day, 30 days, and 10% headroom. Treat this as a planning upper case for motion recording, then correct it with seven days of measured growth.
Four-camera home perimeter
At 4 Mbps, 24 hours, 30 days, and 10% headroom, the estimate is about 5.70 TB. Confirm the formatted and system-reserved space of an 8 TB NVR disk.
Eight-camera shop
Compare 8 cameras at 4 Mbps for 16 hours over 45 days with a 24-hour scenario if recording continues after closing. Sum channel averages when scenes differ.
How to interpret the result
The result is recording space, not necessarily the raw disk capacity to buy. NVR system files, RAID protection, and reserved filesystem space require additional capacity. A 30-day result is an estimate under the entered averages, not a worst-case guarantee.
Error sources and limits
Variable bitrate, night noise, weather, foliage, motion sensitivity, audio, metadata, and vendor formats are not fully represented. Check the vendor design tool before purchase and recalculate from at least seven days of actual storage growth after installation.
Frequently asked questions
Is resolution enough to size storage?
No. Codec, frame rate, quality, and scene complexity can change average bitrate substantially.
How much does motion recording save?
There is no universal percentage. Use continuous recording as an upper case and measure the actual active time.
Does this include RAID overhead?
No. Use this result as the target usable capacity in the RAID calculator.
Last reviewed: 2026-08-21