How long to keep recordings and how to size storage
Recording storage depends on video bitrate, camera count, recording time and retention days. First decide when an event would be reviewed; then estimate capacity and check the recorder's limits. There is no single retention period suitable for every project.
Choose a period around your workflow
Consider how much time can pass between an event and its review. A shop checked daily may have different needs from a warehouse reviewed after a trip. Establish who searches recordings and how clips are exported.
A selected retention period does not replace assessment of the site's particular conditions. Also check that equipment time and date are correct so recordings can be found.
An example with explicit assumptions
Four cameras at an assumed 4 Mbps each, recording continuously for 14 days, produce about 2.4192 decimal TB of video. The calculation is cameras × Mbps × 86,400 × days ÷ 8,000,000.
This does not represent a measured bitrate for a particular model. Audio, metadata, filesystem overhead and changing streams can alter capacity requirements. Leave a margin and confirm the recorder's storage and drive limits.
Validate the actual settings
Event recording can reduce storage use, but the result depends on activity and configuration. Assuming 30% activity does not guarantee that reduction at your site.
Use the calculator to compare retention and bitrate scenarios. Then review recordings made with the intended settings: useful image detail, captured events, disk consumption and date searches.
Questions about this topic
Will a larger drive always work?
No. Check supported capacity, drive bays and recorder compatibility.
Does H.265 establish the number of days?
No. The codec does not replace bitrate, camera count, recording hours and capacity in the calculation.
Is combined recording bitrate my internet requirement?
Not necessarily. Local recording traffic and remote viewing requirements should be calculated separately.