How Much Storage Do I Need for Video Surveillance?

Choosing the right amount of storage for your video surveillance system is one of the most critical decisions you’ll make. Too little, and you risk losing crucial footage of an event. Too much, and you’ve overspent on hard drives you don’t need. The question isn’t simple, because the answer is a precise calculation, not a guess.

As security professionals, we use a formula based on several key technical variables to determine storage needs. This guide will walk you through those same factors so you can understand exactly how much storage *your* system requires.

The 5 Factors That Determine Storage Needs

Your total required storage is a direct result of these five variables working together. Understanding how much it costs to install video surveillance often involves considering storage as a key component.

1. Number of Cameras
This is the simplest factor. The more cameras you have recording, the more storage you will need. The calculation is a simple multiplication of the storage needed for one camera by the total number of cameras.
2. Resolution
This is a major factor. Resolution refers to the clarity and size of the image. A higher resolution camera captures more detail, but creates a much larger file. A 4K camera file can be four times larger than a 1080p camera file, requiring four times the storage.
3. Frame Rate (FPS)
Frame Rate, measured in Frames Per Second (FPS), determines how smooth the video motion appears. Standard video is 30 FPS. While reducing to 15 FPS can cut storage needs nearly in half, it results in choppier video, which may not be suitable for all applications.
4. Compression & Bitrate (H.265 vs. H.264)
This is the most important technical factor. Compression is the technology used to shrink video file sizes. The modern standard is **H.265 (or HEVC)**, which is about 40-50% more efficient than the older H.264 standard. This means an H.265 camera can store twice as much video on the same hard drive as an H.264 camera, with no loss in quality.
5. Recording Schedule (Continuous vs. Motion)
Setting your cameras to record only when motion is detected can dramatically reduce storage needs compared to recording 24/7 (continuous). For low-traffic areas, this can reduce storage usage by 90% or more.
6. Retention Period
This is the number of days you need to keep your footage (e.g., 14, 30, 60 days). This is a direct multiplier. Storing 30 days of video requires exactly twice the storage as storing 15 days.

Sample Storage Estimates

To see how these factors interact, let’s look at a common scenario: a system with **4 cameras recording continuously for 30 days** using modern H.265 compression.

Camera Resolution Frame Rate Estimated Required Storage (TB)
2MP (1080p) 15 FPS ~ 2.5 TB
4MP (2K) 15 FPS ~ 5.0 TB
8MP (4K) 15 FPS ~ 10.0 TB
8MP (4K) on Motion Record (Moderate Traffic) 15 FPS ~ 2.0 – 3.0 TB

How to Calculate Your Specific Storage Needs

Follow this simple, professional process to get a precise answer.

How to Calculate Your Video Surveillance Storage Needs

  1. 1. Determine Your Retention Period

    Decide the number of days you need to keep recorded footage (e.g., 14, 30, 60, or 90 days). This is your most important baseline, often dictated by industry regulations or insurance requirements.

  2. 2. List Your Cameras and Their Settings

    For each camera, note its resolution (e.g., 4MP/2K), frame rate (FPS), and desired recording schedule (continuous or motion-only).

  3. 3. Use a Professional Online Calculator

    Input your data into a reputable online security camera storage calculator. Leading brands like Western Digital or Seagate offer excellent free tools. This will give you a precise estimate in terabytes (TB).

  4. 4. Add a ‘Buffer’ of 20-25%

    Always add extra capacity. This accounts for more complex scenes that require a higher bitrate, potential future camera additions, or a need to extend your retention period temporarily after an incident.

Conclusion: A Calculated Decision

Determining your video surveillance storage needs is a science, not a guess. By understanding the key factors of camera count, resolution, frame rate, compression, and retention, you can accurately calculate the required capacity. This ensures your system will reliably store the footage you need, when you need it, without overspending on unused space. The question of “Can you install surveillance cameras around my property?” often leads to these important storage considerations.