ELECTRONICS · CALCULATOR

CCTV hard disk and bandwidth sizing

Free CCTV hard disk and bandwidth sizing: get storage incl. overhead from cameras, bitrate per camera, retention, recording per day and storage overhead.

Written by Chameera Sampath · Not yet reviewed by a licensed electrician. See the methodology.

US (NEC) only · NFPA 70 / NEC — locally adopted editionDefaults are US values. Verify the locally adopted NEC edition and project data.Official reference ↗

Project inputs

Measurements

Cameras

Bitrate per camera

Mbps

Retention

days

Recording per day

Storage overhead

Updates as inputs change. Unit changes preserve the same physical values.

THE MATH BEHIND THE ANSWER

Method & assumptions

GB = cameras × Mbps × 10⁶ × hours × 3600 × days / (8 × 10⁹)

Decimal GB; constant bitrate estimate, recording hours and codec affect actual storage.

Results do not check every aspect of an electrical installation. The calculators follow US (NEC) practice only; a regional preset changes defaults such as voltage and units, and no result certifies NEC compliance.

Sources and validation →

Worked example

Cameras: 8 · Bitrate per camera: 4 Mbps · Retention: 30 days · Recording per day: 24 h · Storage overhead: 15 %

Storage incl. overhead: 11,923.2 GB · Recording bandwidth: 32 Mbps

This example uses the stated inputs; results for the entered values appear above.

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