Use the calculator below for early planning, then verify the selected cameras, recording profile, recorder limits and usable disk configuration before ordering hardware.
Direct answer
The short answer
Estimate CCTV storage by multiplying camera count, average bitrate, recording seconds per day and retention days, then converting bits to bytes. This calculator adds a 15% planning reserve. The result is an estimate—not a recorder guarantee—because codec, variable bitrate, frame rate, image complexity, motion schedules, audio, metadata, RAID and drive formatting can change real use.
Estimate CCTV recording storage
Enter the average bitrate for the final recording profile—not only the camera’s maximum bitrate.
Estimate only. Codec, variable bitrate, frame rate, scene activity, night noise, motion schedules, audio, analytics, RAID, drive formatting and recorder limits can change the installed capacity required.
Choose an average bitrate—not only camera resolution
Two cameras with the same resolution can use different storage because codec, frame rate, quality, scene movement, night noise and bitrate control differ. Use a measured or manufacturer-supported average for the approved recording profile, not the maximum network bitrate unless the design intentionally budgets for it.
- H.264 versus H.265 or another supported codec
- Constant versus variable bitrate
- Frames per second
- Day and night scene complexity
- Analytics, metadata and audio
- Camera firmware and recording profile
Continuous and motion recording need different assumptions
Continuous recording uses the selected average around the clock. Motion or event recording can reduce storage, but the savings depend on real scene activity and pre/post-event settings. A busy lobby, tree-lined exterior or noisy night image may record much more than expected.
Has the motion-recording estimate been tested against a representative week at the actual property?
Usable capacity is not the drive-label total
Recorder operating space, drive formatting, reserved capacity, RAID protection and manufacturer limits can reduce usable storage. A recorder with several drives may trade raw capacity for fault tolerance. Confirm supported drive models, maximum bay capacity and the selected array or redundancy method.
Retention must match the operating and privacy plan
More days are not automatically better. A strata or business should connect retention to its documented security purpose, normal incident-reporting delay, privacy exposure and legal or business needs. The configured target should be tested by checking the oldest available recording—not assumed from a capacity worksheet.
Verify the result after commissioning
Once cameras run under actual lighting and activity, compare measured bitrate, available capacity and achieved oldest recording with the estimate. Repeat after major camera, frame-rate, quality, scene or schedule changes.
- Record final camera count and profiles
- Measure average bitrate during representative day and night periods
- Confirm recorder usable capacity
- Check oldest available footage
- Test a sample playback and export
- Document the achieved retention date
- Adjust profiles only within the approved evidence requirements
Frequently asked questions
Questions property teams ask
How much storage does one 4K camera need?+
There is no single number. Codec, bitrate, frame rate, scene activity, recording hours and retention determine the result. Use the actual planned average bitrate.
Does H.265 always cut storage in half?+
No fixed saving applies to every scene and product. It can reduce bitrate versus an equivalent H.264 profile, but the actual result must be measured or verified for the selected equipment.
Can motion recording guarantee a storage reduction?+
No. The reduction depends on real activity, detection quality and pre/post-event settings. Busy or noisy scenes can record almost continuously.
Should a strata keep footage as long as possible?+
Not automatically. Retention should be justified by purpose, reporting delay, privacy and applicable legal or business needs.
Sources & further reading
Primary references
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