NVR Calculator

How much storage do CCTV cameras need?

Storage depends on the bitrate of the video being recorded and how long it is recorded. For each camera group, this calculator uses:

Video storage in TB = cameras × bitrate in Mbps × recorded hours per day × retention days × 0.00045.

It then adds your chosen extra storage percentage. RAID reduces the available drive capacity separately. Audio, system partitions and filesystem metadata are not modelled individually.

For example, 16 cameras recording at an assumed 2.4 Mbps each for 6 hours per day over 30 days need about 3.11 TB of video storage. Adding 20% gives about 3.73 TB. Recording the same streams continuously for 24 hours per day increases these figures to about 12.44 TB and 14.93 TB respectively. These are worked examples, not promises of actual retention.

Recommended settings and custom bitrate

The initial settings are H.265, 25 FPS, motion recording enabled and 20% extra storage. The default 6 recorded hours per day is an editable example. Include footage recorded before and after motion events. For continuous recording, clear the motion checkbox and set your scheduled recording hours.

Our Recommended option is a starting estimate. It scales a 1080p, 25 FPS, H.264 baseline of 4 Mbps by pixel count and frame rate, then applies a factor of 0.6 for H.265 or 5 for MJPEG. These are calculator assumptions, not certified bitrates or guaranteed compression savings. Use Custom to enter a measured or configured recording bitrate for your cameras. Changing the video-format selector does not apply an extra compression discount to a Custom bitrate.

Should I allow 5%, 10% or 20% extra storage?

We suggest 20% for initial planning, particularly when using estimated bitrates and motion recording. An estimated 10 TB of video storage becomes a 12 TB requirement with this setting. This adds 20% to estimated demand; it does not reserve 20% of the final disk capacity.

Consider 10% after checking representative recording usage, including busy periods and night scenes. A 5% allowance leaves little room for variation and is not our general starting point. These percentages are our planning guidance, not a manufacturer standard. No percentage compensates for an unrealistic bitrate or recording-hours assumption.

Motion, scene detail and bitrate control can substantially change video data rates. For variable-bitrate recording, allow headroom and check actual usage after commissioning.

Planning for popular NVR and NAS surveillance systems

Use this calculator with the recording settings from your chosen system. The storage estimate uses bitrate and recording time; it is not an official manufacturer model selector. Check camera channels, incoming bandwidth, maximum HDD size and RAID support for the exact recorder.

Hikvision: Use Custom with a representative recording bitrate when H.265+ is enabled. Hikvision's compression responds to scene activity and bitrate settings, so a fixed extra percentage saving would be unreliable. Measure busy periods and night scenes as well as quiet daytime footage.

Dahua and Uniview: For Dahua Smart H.265+ or Uniview Ultra 265, use the bitrate of the stream actually being recorded. This calculator does not apply a separate smart-codec discount to Custom values. Only choose RAID protection when the specific recorder supports it.

Axis and Hanwha Vision: Axis Zipstream and Hanwha WiseStream can change the recorded bitrate with scene activity and compression settings. Enter a representative measured rate under Custom and retain suitable headroom. Compression does not itself mean that the recorder stores footage only when motion is detected.

Reolink: Include every stream or lens that the recorder saves. Some setups store more than one stream per camera; add those bitrates together for that camera rather than counting just its main stream. Confirm the recorder's drive limits and supported storage layout separately.

Ubiquiti UniFi Protect: Enter the recording bitrate and recording mode appropriate to your cameras. Enhanced Retention can store older footage at a lower quality; that multi-quality retention policy is not simulated by this single-rate estimate.

TP-Link VIGI: Use the bitrate of the stream actually being recorded. H.265 and smart-codec options depend on the camera and configuration. H.265+ is not simulated as a separate saving factor; use Custom when you have a suitable measured bitrate.

Synology, QNAP and ASUSTOR: Use the recording bitrate and schedule selected in your surveillance application. Confirm the particular NAS or NVR's camera compatibility, camera licensing, supported channels, incoming bandwidth and drive configuration separately. A storage-capacity match alone does not establish that a recorder can handle the camera workload.

NVR Calculator questions

Does H.265 always use a fixed percentage less storage?

No. H.265 can improve compression, but the resulting bitrate depends on the camera, scene, quality settings and encoder. At the same entered bitrate and recording duration, the storage calculation is the same regardless of the format label. Our Recommended option uses a rough planning factor; Custom uses the bitrate you enter.

Does motion detection automatically reduce HDD usage?

Only when it reduces the footage actually stored. Enabling detection alerts while continuing to record all day does not produce the motion-only saving shown here. Busy scenes, false triggers and event buffers can increase recording hours. If your site needs continuous footage, calculate continuous recording.

Do more drive bays mean more supported cameras?

Not necessarily. The bars compare estimated storage capacity. Camera channel limits, decoding and incoming recording bandwidth depend on the particular recorder. The smallest storage fit is not automatically a suitable NVR model.

How is drive-failure protection calculated?

The one-drive protection option models RAID 1 with two drives and RAID 5 with four, eight or twelve drives. The two-drive protection option models RAID 6, which needs at least four drives. The comparisons cover enclosures with up to 12 bays. These are calculator assumptions; select a recorder that supports the intended layout.

Why might the actual recording days differ?

Bitrate, scene activity, motion recording hours, audio, system overhead and recorder retention policies affect actual usage. Check representative recordings after installation and adjust the plan. The extra allowance is a buffer, not a retention guarantee.

Browse related surveillance products

Explore TP-Link VIGI, Ubiquiti and Synology products, or compare our network video recorders and hard drives.

Need help planning your camera system?

Use Ask ACE for advice to discuss cameras, recorder capacity and recording requirements. Include your phone number and select cabling or installation if needed. For a separate disk-layout estimate, use our RAID Calculator.