CCTV storage calculator

How much storage do you need, or how long will your HDD record? Estimate from bitrate and recording time, then compare your settings.

Find required storage Find recording days

Days to retain

days

Additional allocation margin

20% means calculated data × 1.20. Set 0% to see the data-only estimate.

Mix camera resolutions in one system

Combine 2MP, 4MP, 8MP and other resolutions. Each group has its own camera count, codec, FPS and recording schedule.

Add a resolution group

Resolution to add

Cameras to add

New groups start with H.265, 15 FPS, 24 hours/day and a table bitrate estimate. Every setting can be edited.

Example: H.265, 15 FPS, 24 hours/day, 30 days and 20% margin.

Up to 16 groups. Use the bitrate of the recorded stream. HDMI is display output and does not enter this formula.

Storage by resolution / camera group

Scroll the table horizontally to see camera counts, data, margin and totals.

Data, margin and total allocation for each camera group
Group / resolution	Cameras	Daily dataGB	Data onlyTB	MarginTB	With marginTB

Settings have changed. Calculate again before printing a result.

CCTV storage calculation report

Recorded data per day
Data-only capacity

Camera settings and allocation by group

Group / settings	Cameras	Data/dayGB	AllocationTB

Formula and assumptions

Data (GB) = cameras × (video Mbps + audio Kbps ÷ 1,000) × hours/day × days × 0.45

Total (TB) = data ÷ 1,000 × (1 + margin% ÷ 100)

Decimal units: 1 TB = 1,000 GB. Use capacity after RAID/system deductions. Margin adds to the data estimate; it is not the free-space percentage. Totals use unrounded values.

Actual consumption varies by device, scene, image quality and recording settings. Results estimate retention and do not guarantee recording days.

How the calculation works

Uses decimal units: 1 TB = 1,000 GB and 1 Mbps = 1,000,000 bits per second. Codec and FPS are not multiplied again once bitrate is known.

Required capacity

Data (GB) = cameras × bitrate (Mbps) × hours/day × days × 0.45

Total (TB) = data ÷ 1,000 × (1 + margin% ÷ 100)

Recording retention

Days = available capacity (TB) × 1,000 ÷ [daily data (GB) × (1 + margin% ÷ 100)]

For multiple groups, add each group’s daily data first. Audio bitrate is added to video bitrate when specified.

Example with a specified bitrate

One camera at 1.78 Mbps, recording 24 hours/day for 30 days, uses 576.72 GB of data. With 20% additional margin, allocate approximately 692.06 GB or 0.692 TB.

With 1 TB available and the same camera settings, retention is about 52.02 days at 0% margin, or 43.35 days with 20% additional margin.

Questions to answer before choosing an HDD

What if I do not know the bitrate?

Choose “Estimate from settings”, then select H.264, H.264+, H.265 or H.265+ to use the Hikvision reference for the selected resolution and FPS. Plus codecs use the target bitrate rows as planning estimates. Actual bitrate depends on device, quality and scene. Use “Enter bitrate manually” when you have the recorded stream’s average bitrate.

How are H.264+ / H.265+ calculated?

The tool uses each codec’s Hikvision table target bitrate to estimate storage, without a second fixed-percentage reduction. A target is not a measured site average or instantaneous Max. Bitrate. You can manually enter the device’s configured Max. Average Bitrate for planning, or a representative long-term recorded average. Smart Codec behavior and recommendations vary by manufacturer and model.

How much storage does H.265 save?

The difference depends on the recorded bitrate. This tool uses the table value for each setting or your manual value; it does not apply a second codec discount.

How do I estimate motion-only recording?

Enter the expected hours actually recorded per day, including pre-event and post-event footage. This varies with activity. Use 24 hours for continuous recording.

Does 20% margin mean 20% free space?

This tool adds to the calculated data: 1 TB of data plus 20% margin needs 1.2 TB. Keeping 20% of the final capacity free instead needs 1 ÷ 0.8 = 1.25 TB, which is a different definition.

Are the recording days guaranteed?

Results estimate the supplied inputs. VBR, busy or night scenes, audio, metadata and additional recorded streams can change consumption. Compare with actual usage and check the NVR/NAS limits before choosing disks.

References and scope

Formula version 1 · Reviewed 5 November 2026 · Table values use Kbps ÷ 1,000 to display Mbps · Estimates recorded streams, not NVR bandwidth limits.

Ask SyncTech to review your requirements