Reviewed, sourced guidance

CCTV storage questions answered

Published 29 Sept 2026Reviewed 29 Sept 20261 min read

Direct answer

Decimal storage terabytes equal megabits per second times 0.45, times recorded hours per day, times retention days, divided by 1,000; find the bitrate in the encoder or NVR configuration; the ICO sets no fixed retention period, so the purpose decides.

The storage, bitrate and retention questions behind most CCTV planning checks, answered within the site’s scope and cited sources.

Key takeaways

Bitrate lives in the encoder or NVR settings.
The 0.45 factor converts decimal megabits to gigabytes per hour.
Recorder limits are throughput plus decoding, not just disk.
Retention follows purpose, not a fixed UK rule.

Evidence note

Source-led CCTV storage and throughput planning information with visible assumptions and limits.

View the full evidence note

Produced by: CCTV Storage Calculator
Jurisdiction: UK buyer information. Data-protection guidance is UK-wide and the ICO currently marks its surveillance guidance as under review.
Page scope: Frequently asked questions about CCTV storage and throughput estimation.
Default subject: Decimal video-storage and aggregate recording-throughput arithmetic from user-entered stream bitrates and schedules.
Excludes: CCTV system design, installation, security or compliance advice; Codec-to-bitrate conversion or a claim about image quality; A legal retention recommendation or data-protection determination; NVR, NAS, hard-drive sizing, product selection or manufacturer endorsement; Installer listings, rankings, referrals, lead capture or quotations
Published: 2026-09-29
Reviewed: 2026-09-29
Commercial status: Information preview only. No CCTV provider is listed, no enquiry is collected, and no lead or affiliate route is active.

Answers restate cited sources and tested arithmetic for planning. They are not a recorder recommendation or a data-protection determination.

How this guidance is produced · About this calculator and its limits

How do I calculate CCTV storage in terabytes?

Multiply each camera group’s entered megabits per second by 0.45, by recorded hours per day, and by retention days, then divide by 1,000 for decimal terabytes.

Add groups together for different streams or schedules; the result is a video-data estimate, not a drive recommendation.

Sources for this section: Seagate UK, video storage calculator for surveillance (observed 2026-09-25; manufacturer tool)

What bitrate should I enter?

Check the camera encoder or NVR channel configuration for the selected stream’s bitrate and recording schedule.

For variable bitrate, use representative measured data from the actual system; a resolution-to-bitrate table is not a device specification.

Sources for this section: Hikvision, DS-9616NXI-I8R/VPro NVR data sheet (observed 2026-09-25; model-specific example only)Axis Communications, Bitrate control for IP video (white paper, March 2023; observed 2026-09-27)

How do I check a recorder can handle my cameras?

Sum the configured rates for streams expected to arrive concurrently as a first incoming-throughput check, then compare with the exact recorder limit.

Separately check decoding capability and retained video data; they answer different questions.

Sources for this section: Western Digital, surveillance storage estimator and limitations (observed 2026-09-25; manufacturer tool)

How long should CCTV footage be kept?

The ICO states that UK GDPR and the Data Protection Act 2018 do not set one minimum or maximum surveillance retention period.

The purpose should determine the necessary period, and footage should not be kept longer than needed; the ICO marks its surveillance guidance as under review, so recheck current pages.

Sources for this section: ICO, storage limitation and retention for surveillance systems (observed 2026-09-25; guidance under review)

Next steps

Enter your measured bitrates and schedules in the storage tool.
Recheck the ICO retention guidance before setting any deletion policy.

Sources

Open the storage tool