Skip to content
Sky Security System

Free tool

CCTV storage calculator

Work out how many TB of hard disk your DVR or NVR needs for your cameras and the number of days you want to keep footage.

You need about

8.55 TB

for 8 cameras x 30 days, using 3 Mbps per camera. That is about 32.4 GB per camera per day, plus 10% headroom.

  • 3 x 4 TB disks
  • 2 x 8 TB disks
  • 1 x 12 TB disks

Check your recorder has enough disk bays. RAID or redundancy needs extra disks.

This is a planning estimate. Actual storage depends on scene activity, lighting, frame rate and camera settings. We size every system after a site survey.

How it works

The formula behind the number

Storage per camera per day is the camera's bitrate in Mbps multiplied by 10.8 GB (one megabit per second for 24 hours is 10.8 GB). Multiply by the number of cameras and the days you want to keep, then add 10% headroom for the file system. Motion-based recording is modelled as recording about 40% of the day.

Typical bitrates used: H.265 at 2, 4, 5 and 8 MP is 1.5, 3, 4 and 6 Mbps; H.264 is 3, 5, 6 and 10 Mbps. These assume 15 to 25 frames per second in normal scenes.

Questions

CCTV storage, answered

It depends on the bitrate. As a planning figure, a 4 MP camera on H.265 recording continuously at about 3 Mbps uses roughly 32 GB per day. A 2 MP camera on H.265 at about 1.5 Mbps uses roughly 16 GB per day. Each 1 Mbps of bitrate is about 10.8 GB per day.

Decide before buying the hard disk, because adding storage later costs more. Many shops and offices keep 15 to 30 days. Societies and sites that discover problems late often choose 30 days or more. Keep footage for as long as you realistically need to review an incident.

Yes, usually. H.265 can cut storage by roughly a third to a half for the same picture quality, but only if both the cameras and the recorder support it. Savings vary with the scene.

Real bitrates rise with busy scenes, night infrared, high frame rates and high-quality presets. If you know your camera's actual bitrate from its settings page, enter it in the optional bitrate box for a better answer.

Yes. CCTV recorders write to disk around the clock, so use disks built for continuous surveillance recording rather than ordinary desktop disks, and check your recorder's maximum supported disk size and number of bays.

Use this calculator on your own site

Housing society, builder or facility-management website? You are welcome to link to this page:

<a href="https://skysecuritysystem.in/tools/cctv-storage-calculator">CCTV storage calculator by Sky Security System</a>

Free site survey

Want the right disk size for your site?

Our engineers survey your site, size the cameras, recorder and storage together, and send an itemised quotation.

  • Free site survey by our own engineers
  • Itemised, no-obligation proposal
  • Genuine Hikvision, CP Plus & Dahua with warranty
  • Installation, service and AMC from one team
+91 85528 98716 WhatsApp

Read before you decide

CCTV buying guides

CCTV installation services · How many cameras do you need?