Multiple Camera Storage Calculator
Planning storage for a security camera system starts with four practical details: how many cameras record, their average bitrate, how long they record each day, and how many days of footage you want to keep. The Multiple Camera Storage Calculator combines these inputs to estimate the recording space you need in decimal terabytes (TB).
What the Multiple Camera Storage Calculator does
The calculator estimates the storage needed for a group of cameras that share the same average bitrate and daily recording schedule. It is useful when you are comparing security camera systems, choosing a network video recorder (NVR), or deciding how much hard drive capacity to purchase.
The result is labeled Estimated storage and displayed in TB to two decimal places. The calculation uses decimal storage units: 1 TB equals 1,000,000 MB. The estimate covers the recording data calculated from your inputs; it does not include filesystem, RAID, recording software, or other system overhead.
Because real camera bitrates and recording patterns can change, treat the result as a planning estimate. Leave extra capacity when purchasing drives, especially if you need to meet a specific retention period consistently.
How to use the Multiple Camera Storage Calculator
Enter the details for the cameras you want to include in the estimate:
- Number of cameras: Enter the number of cameras that will record using the same average bitrate and schedule. The calculator accepts whole numbers from 1 to 1,000.
- Average bitrate per camera (Mbps): Enter the average recording bitrate for one camera in megabits per second. The accepted range is 0.1 to 100 Mbps, in increments of 0.1 Mbps. Include audio in this figure if your cameras record audio.
- Recording hours per day: Enter the average number of hours each camera records per day, from 0.1 to 24 hours. Use 24 for continuous recording throughout the day.
- Retention period (days): Enter the number of days you want to keep the footage, from 1 to 3,650 days.
Read the Estimated storage result as the approximate space required for the combined recordings. The default settings are illustrative, so replace them with values that reflect your cameras and recording plans.
If different cameras use different bitrates or schedules, estimate each group separately and add the results. For example, you could calculate outdoor cameras and indoor cameras as separate groups if their recording settings differ. Remember that each displayed result is rounded to two decimal places, so adding rounded results can introduce a small rounding difference.
How the Multiple Camera Storage Calculator formula works
The formula multiplies the number of cameras by the average bitrate, recording time, and retention period. It then converts the total from megabits to decimal terabytes:
Estimated storage (TB) = Number of cameras × Average bitrate per camera (Mbps) × Recording hours per day × Retention period (days) × 3,600 ÷ 8 ÷ 1,000,000
There are 3,600 seconds in an hour, so multiplying the recording hours by 3,600 converts the time to seconds. Dividing by 8 converts megabits to megabytes. Dividing by 1,000,000 then converts decimal megabytes to decimal terabytes.
Worked example: Four cameras recording continuously
Suppose you have four cameras, each with an assumed average bitrate of 4 Mbps. You plan to record for 24 hours per day and retain the footage for 30 days. These are the calculator’s illustrative default inputs:
- Number of cameras: 4
- Average bitrate per camera: 4 Mbps
- Recording hours per day: 24
- Retention period: 30 days
The calculation is 4 × 4 × 24 × 30 × 3,600 ÷ 8 ÷ 1,000,000 = 5.184 TB. The calculator displays this as 5.18 TB because it rounds the result to two decimal places. This is the estimated recording data before storage overhead or an allowance for changing conditions.
Use cases for the Multiple Camera Storage Calculator
Planning a home security system
Homeowners can use the estimate to compare a few recording scenarios before choosing storage. For instance, a system recording continuously for 30 days requires more space than the same cameras recording for an average of 12 hours per day, assuming the bitrate remains the same.
Sizing storage for a business
Shops, offices, warehouses, and other businesses may want footage available for different lengths of time. Changing the retention period in the calculator shows how storage requirements grow as the number of days increases. Any retention target should reflect the organization’s own needs and applicable requirements.
Comparing camera settings
Bitrate has a direct effect on storage. If all other inputs stay the same, doubling the average bitrate doubles the estimated recording space. You can compare assumed bitrates to understand the storage trade-off, while also considering whether the resulting image quality suits your security needs.
Estimating an expansion
If you plan to add cameras with the same average bitrate and schedule as your existing cameras, update the number of cameras to estimate the new total. Alternatively, calculate the additional cameras as a separate group to see their estimated contribution.
Other factors to consider when calculating Estimated storage
Variable bitrate: Many cameras do not produce data at a constant rate. Scene activity, lighting changes, and image detail can affect the average bitrate. A busy entrance may use storage differently from a quiet room, even when the cameras have similar settings.
Compression and image settings: Compression method, resolution, frame rate, and quality settings can influence bitrate. The calculator uses the bitrate you enter; it does not determine a bitrate from these settings. Use a representative average for your actual configuration when one is available.
Motion-based recording: If cameras record only when motion occurs, the daily recording time is an estimate. Activity can vary from day to day, so an assumed average may not protect against unusually busy periods. Continuous recording is easier to model because the schedule is more predictable.
Audio: When audio is recorded, include its data in the average bitrate per camera. Entering a video-only bitrate for a system that also records audio can underestimate the total storage needed.
System overhead and drive capacity: The result excludes filesystem, RAID, recording software, and other storage overhead. A drive’s advertised capacity also may not all be available for recordings. Allow extra room when selecting drives, and check how your recording system manages its usable storage.
Decimal units and rounding: The calculator uses decimal TB, while some devices or software may display capacity using different units. It also shows only two decimal places. A very small calculated amount can therefore appear as 0.00 TB even though the underlying estimate is greater than zero.
Multiple Camera Storage Calculator FAQ
How much storage do four security cameras need for 30 days?
In the illustrative default example, four cameras averaging 4 Mbps each and recording 24 hours per day need an estimated 5.18 TB for 30 days. A different bitrate or recording schedule will produce a different result, and additional capacity is needed for overhead and practical variation.
Does the calculator support cameras with different bitrates?
Each calculation assumes every included camera has the same average bitrate and recording schedule. For cameras with different settings, calculate each matching group separately and add the estimates, allowing for rounding in the displayed results.
Should I enter the camera’s maximum bitrate or average bitrate?
Enter the average bitrate per camera, including audio if recorded. A maximum bitrate may be higher than the actual average, while an average that does not represent busy periods may underestimate usage. Choose an assumption that reflects your recording conditions and leave additional capacity.
Can I use the calculator for motion-only recording?
Yes. Enter your assumed average number of recording hours per day. Since motion activity can vary, the result is only as reliable as that assumption. Consider how a busier-than-usual period could affect your retention time.
Why does my recorder show a different amount of usable storage?
Your recorder may use a different capacity display or reserve space for its filesystem and software. RAID configuration and other overhead can also reduce the space available for footage. The calculator estimates recording data in decimal TB and does not deduct those amounts.