Surveillance Storage Calculator — by Shield Low Voltage
Describe the cameras and how long you want to keep the footage. This works out the real bitrate, the drives to buy, and the recorder that holds them — including the storage that RAID and drive formatting quietly take back before you record a single frame.
Buy this much
0TB
— · 0 TB of actual recording
Where the numbers come from
The Honest Version
Nearly every calculator online multiplies a fixed bitrate by a number of days. Four things wreck that answer, and all four are in the maths above.
A 4K camera does not have “a” bitrate. The same sensor writes a fraction as much watching a locked storeroom as it does watching a parking lot with trees moving behind it. Codec matters more still: H.264 costs roughly ninety per cent more than H.265 for the same picture. Calculators that ask only for megapixels are guessing.
Doubling from 15 to 30 fps does not double storage. Video compression describes most frames as differences from the one before, so the extra frames are cheap — the real increase is nearer sixty per cent. Assume it doubles and you buy drives you did not need.
Recording on motion sounds like it cuts storage by ninety per cent. On a real site it is closer to seventy on a quiet building and half on a busy one, and it varies by season. It is also the setting most likely to lose you the footage you needed, because the seconds before the camera decided something was happening are usually the important ones.
Drives are sold in decimal terabytes and formatted in binary ones, so an 8 TB drive presents about 7.3 TB before anything else happens. Then RAID takes its share — parity, or half the array if you mirror. Then you leave headroom, because a recorder run to the brim overwrites unpredictably and wears its drives faster. Four 8 TB drives in RAID 5 is 32 TB on the invoice and around 20 TB of usable recording.
Before You Buy Drives
A surveillance recorder writes continuously, from many cameras at once, forever. A desktop drive is designed for a machine that is idle most of the day, and it fails early doing this — usually eighteen months in, usually all of them at once, because they were bought together.
Use surveillance-rated drives — WD Purple, Seagate SkyHawk or the equivalent. They are built for sustained sequential writes and for sitting in a warm enclosure with several other drives vibrating beside them. On any array that matters, buy at least one spare from a different batch and keep it on the shelf.
And decide early whether the footage is evidence. If it might ever be handed to an insurer, an attorney or a police department, single drives are a false economy: the failure takes the footage with it, and it always fails during the month you needed it.
Platform Reality
The calculator above sizes local storage, because that is what people are usually trying to work out. It is not the only way to build a camera system, and we install all three.
Local recording on a UniFi NVR, no per-camera fee, footage stays on your property. The calculator above recommends from this line, from the single-bay NVR Instant up to the sixteen-bay Enterprise NVR. This is the right answer for most homes and most small commercial sites.
Storage lives on the camera itself — typically 30 to 365 days of onboard solid state, with the cloud holding the index and anything you flag. There is no NVR to size, no array to rebuild, and no closet full of spinning drives. You pay a licence per camera instead, and that is the honest trade.
Clip-based cloud recording by default, with a Stream Video Recorder on site when you want continuous footage as well. Best where the cameras are part of a monitored alarm rather than a standalone surveillance system — the video and the alarm answer to the same app.
Utah — Wasatch Front & Back
The number above is the honest arithmetic. Turning it into a system means choosing lenses for the distances involved, putting the recorder somewhere it stays cool, and pulling the cable that feeds it — which is the part we do. Bring us your numbers, or let us come and take them.
