CCTV Storage Calculator: How Much Storage Do Camera Recordings Need?
Every camera project asks two things: how many days will the disks hold, and how much space does the retention period need? This CCTV storage calculator estimates total storage, bitrate per camera, daily recording volume and, if footage goes to the cloud, the upload speed needed, from camera count, resolution, codec, frame rate, recording mode and retention days. The assumptions are explained below.
All calculations run in your browser; nothing you enter is sent to a server.
Plan the Calculated Capacity in the Cloud
Once total storage and upload needs are clear, the next step is deciding where the footage will live. The MAV Cloud team can help work out the right setup from camera count, retention period and line capacity.
Bitrate, not resolution, drives storage
The number that tells you how much data a camera writes to disk is its bitrate: the amount of data produced per second, in Mbps. Resolution is only one of the factors behind it. The same 4 MP camera writes far more at a busy car park entrance than in a quiet corridor.
The calculator therefore works directly from bitrate. The formula is: storage (TB) = cameras × Mbps per camera × 3,600 × 24 × recording share × days ÷ 8 ÷ 1,000,000. If your recorder (NVR) shows the real bitrate of each camera, enter it in the optional field so the result uses a measurement instead of an assumption.
Default bitrates and where they come from
Without a measured bitrate, the calculator assumes the following at 15 fps for an average scene: with H.264, 4 Mbps for a 2 MP camera, 6 Mbps for 4 MP and 12 Mbps for 8 MP (4K); with H.265, roughly half of that (2, 3 and 6 Mbps). When the frame rate changes, the value scales linearly with fps/15, but never drops below 40% of the default.
These defaults deliberately sit at the upper end. Hikvision’s published recommended bitrate table lists about 2 Mbps for 1080p H.264 at 15 fps and about 4 Mbps at 30 fps, and notes that values can be raised by 20-30% for complex scenes (Hikvision, recommended bitrate table). Night vision, rain, moving trees and crowds all push bitrate up.
Codec choice: H.264 vs H.265
H.265 (HEVC) is the successor to H.264 and delivers similar image quality at a lower bitrate. Manufacturer tables list H.265 at roughly half of H.264, and the calculator uses the same ratio. Switching to H.265 with the same cameras and retention roughly halves the disk space needed.
Many manufacturers add a “smart codec” layer that encodes static parts of the scene with less data. Its effect varies widely by scene, so the calculator has no separate option for it; with a smart codec enabled, enter the real bitrate shown on the NVR.
Frame rate and scene activity
Frame rate (fps) is the number of images recorded per second. For security recording 15 fps is generally enough; 30 fps suits spots like cash desks, turnstiles or licence plate capture. In the calculator, raising a 2 MP H.265 camera to 30 fps takes bitrate from 2 Mbps to 4 Mbps and doubles the storage needed.
Scene activity matters just as much: constant traffic, moving trees or infrared image noise at night make compression less efficient.
Continuous or motion-triggered recording?
With continuous recording the camera writes to disk around the clock. With motion-triggered recording, footage is only saved when something moves in the scene; in this mode the calculator uses the “share of time with motion” field and multiplies storage by it. Depending on the site, that share usually falls between 10% and 50%.
Motion recording saves space, but too low a sensitivity can miss the start of an event and too high a sensitivity records shadows and light changes. A mixed setup, with continuous recording at critical points and motion recording elsewhere, is a common choice.
Worked examples
The table below uses the calculator’s own formula; every row assumes 15 fps.
| Scenario | Bitrate per camera | Total storage | Cloud recording upload |
|---|---|---|---|
| 16 cameras, 2 MP, H.265, continuous, 30 days | 2 Mbps | ≈10.4 TB (≈0.35 TB/day) | ≈38 Mbps |
| 8 cameras, 2 MP, H.264, 30% motion, 30 days | 4 Mbps | ≈3.1 TB | ≈11.5 Mbps |
| 32 cameras, 4 MP, H.265, continuous, 15 days | 3 Mbps | ≈15.6 TB (≈1.04 TB/day) | ≈115 Mbps |
When using this as an NVR storage calculator, treat the result as usable space. RAID overhead, file system overhead and the free space you keep so disks never fill completely all raise the raw capacity you need to buy.
Retention period and KVKK
Required retention depends on the sector, contracts and internal security policy; some sectors have rules that set a period. Retention multiplies storage directly: going from 30 to 60 days doubles the space required.
Camera footage that makes a person identifiable is personal data. Under the general principles of Türkiye’s data protection law (KVKK), it should be kept only as long as its purpose requires and then deleted or destroyed. Setting the right period is a legal assessment, and this page is not legal advice; the backup side of the topic is covered in our KVKK-compliant data backup guide.
On-Site, in the Cloud, or Both
Which cameras record to the cloud and which stay local depends on line capacity and retention needs. The right model can be reviewed together based on your current cameras and recorder.
On-premises NVR, cloud recording and hybrid setups
With an on-premises NVR, footage sits on the disks of a device on site. It does not depend on the internet connection, but if the device is stolen, burns or a disk fails, the footage goes with it.
With cloud recording, footage is written over the internet to remote storage and becomes independent of on-site hardware. In a hybrid setup, recording continues locally while a copy of critical cameras or event clips goes to the cloud.
Upload bandwidth planning for cloud recording
For cloud recording, upload speed is what counts, not download. As a security camera bandwidth calculator, the tool works out upload as cameras × Mbps × recording share and adds 20% headroom. This figure should be capacity you can dedicate all day, not the advertised peak speed of the line; office traffic and backups on the same line must fit too. The bandwidth entry in our glossary explains the term.
In motion mode the calculator gives an average; when activity peaks, momentary demand rises above it. On sites with limited upload, common approaches are sending a lower-resolution sub-stream to the cloud instead of the main stream, or uploading event clips only.
Securing recordings
Footage is both personal data and potential evidence. The basics are encrypting footage in transit and at rest, limiting access to authorised people, and keeping access logs of who viewed or exported which recording.
Changing default recorder passwords and updating firmware belong on the same list.
Common mistakes
- Looking at resolution alone: two cameras with the same resolution can produce very different bitrates depending on scene and settings.
- Ignoring night footage: image noise in infrared mode raises bitrate, and disks fill sooner than planned.
- Treating raw disk capacity as usable space: after RAID and file system overhead, noticeably less space remains.
- Planning upload on peak speed: cloud recording is continuous and should be sized on the capacity the line can spare all day.
CCTV Cloud at MAV Cloud
MAV Cloud offers a CCTV Cloud service for storing camera recordings in the cloud. The figures from this calculator are a useful starting point for sizing it. For archive or backup needs beyond recordings, S3-compatible object storage is also available.
The storage infrastructure is located in Türkiye, at the Equinix İstanbul data center. Keeping footage that counts as personal data in the country simplifies the transfer assessment.
MAV Cloud’s service level agreement sets first-response targets of 15 minutes for critical, 1 hour for high, 4 hours for medium and 1 business day for low priority. MAV Cloud is certified to ISO/IEC 27001, ISO/IEC 27701, ISO 22301, ISO/IEC 20000 and ISO 9001.
Frequently Asked Questions
How many days of recording will my current disks hold?
Set retention to 1 day in the calculator to get the daily recording volume, then divide usable disk space by that volume. Sixteen 2 MP H.265 cameras recording continuously write about 0.35 TB a day, so 4 TB of usable space holds roughly 11 days.
How accurate is the CCTV storage calculator?
The result is only as accurate as the bitrate behind it. The defaults are upper-range estimates for an average scene; with the real bitrate from your NVR, the result gets very close to reality.
How much storage for CCTV does H.265 save?
Manufacturer tables put H.265 at roughly half the bitrate of H.264, so space needed for the same cameras and retention roughly halves. Your recorder and viewing software must support H.265.
How much upload speed does cloud recording need?
Continuous capacity equal to cameras × bitrate × recording share, plus the calculator’s 20% headroom. Sixteen 2 MP H.265 cameras recording continuously need about 38 Mbps of steady upload.
Is anything I enter stored?
No. The calculation runs in your browser and your inputs are not sent to a server.
Free Assessment of Your Camera Setup
Share your camera count, recorder, retention period and internet line details, and local, cloud or hybrid recording options can be reviewed together.
More infrastructure calculators are on our tools page.