Security Camera Retention Calculator

Work out how many days of footage a fixed amount of disk holds for your camera count and bitrate.

About Security Camera Retention Calculator

Daily consumption is the aggregate write rate converted from megabits to gigabytes. Dividing available capacity by that figure gives the rolling window before the oldest footage is overwritten. Retention is usually a policy or insurance requirement, and discovering the window is only nine days long after an incident is too late.

Formula

Security Camera Retention

Retention days = capacity ÷ (bitrate × 3600 × hours ÷ 8000 × cameras × (1 − saving))

capacity: Usable disk in the recorder after RAID and formatting
saving: Reduction from recording only on motion

Worked example

With the default values below, Security Camera Retention Calculator returns Retention Achieved of 51.4. Change any input above and every figure here is recalculated in your browser.

Inputs used

Available storageminimum 0.1 TB: 8 TB
Number of camerasminimum 1: 6
Bitrate per cameraminimum 0.1 Mbps: 4 Mbps
Recording hours per dayaccepts 0.5–24 h: 24 h
Saving from motion-only recordingaccepts 0–100 %: 40 %

Results

Retention Achieved: 51.4 days
Retention Achieved: 7.35 weeks
Storage Consumed per Day: 155.52 GB
Storage Needed for 30 Days: 4.666 TB
Verdict: Meets a 30-day retention policy

Step by step

1Values used
2Security Camera Retention
3Retention Achieved= 51.4 days
4Retention Achieved= 7.35 weeks
5Storage Consumed per Day= 155.52 GB
6Storage Needed for 30 Days= 4.666 TB
7Verdict= Meets a 30-day retention policy

Assumptions and limits

The result is derived only from the 5 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 3 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

How is Security Camera Retention calculated?

Retention days = capacity ÷ (bitrate × 3600 × hours ÷ 8000 × cameras × (1 − saving)) Daily consumption is the aggregate write rate converted from megabits to gigabytes. Dividing available capacity by that figure gives the rolling window before the oldest footage is overwritten.

Why does Security Camera Retention matter?

Retention is usually a policy or insurance requirement, and discovering the window is only nine days long after an incident is too late.

What values do I need to enter?

This calculator takes 5 inputs: Available storage, Number of cameras, Bitrate per camera, Recording hours per day, Saving from motion-only recording. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.