Free UK tool
Security Camera Storage Calculator
How many days of footage does a microSD card actually hold, and is a cloud subscription worth it? Pick your camera resolution and recording style, and see how fast your storage fills — before you buy.
This free calculator works out how much storage a UK home security camera setup really needs, whether you record continuously or only on motion. It also puts a yearly pound figure on the equivalent cloud plan, so you can compare local storage against subscription costs honestly.
Bitrates are typical values from manufacturer specifications and published reviews — not our own bench measurements. Actual figures vary with scene complexity and codec.
Most battery doorbells and indoor cams
A quiet back door might be 1–2 hours; a busy front pavement 4+.
Your storage maths
5.4 GB
recorded per day, all cameras
24 days
of footage on 128 GB
£60
per year for an equivalent cloud plan
That's comfortably more than the 7–14 days most households want before footage loops. Local storage is doing the job here — a subscription would mostly buy you off-site backup, not more history.
How the maths works
A camera's bitrate in megabits per second converts to storage like this: Mbps × 3,600 seconds ÷ 8 bits ÷ 1,000 gives gigabytes per hour. A 1080p camera at 2 Mbps uses about 0.9 GB per hour of recorded footage. Multiply by how many hours a day the camera is actually recording, then by the number of cameras.
The honest caveat: modern H.265 codecs and variable bitrates can halve these figures in quiet scenes, and a busy scene with rain, trees or passing headlights can push them up by half. Treat the result as a planning number, then check your camera's app after the first week — most tell you the real daily usage.
Common questions
How much storage does a 1080p security camera use per day?
Recording continuously at a typical 2 Mbps, roughly 21 GB per day. With motion-only recording on a normal UK street it's usually 3–6 GB per day, which is why a 128 GB card lasts weeks rather than days in most homes.
Is local storage or a cloud subscription better value?
A £10–20 microSD card storing two weeks of footage beats a £30-per-camera yearly plan on cost every time. The cloud plan earns its money one way: off-site backup, so footage survives even if the camera itself is stolen. Some cameras offer both — card for history, cheap cloud tier for the few clips that matter.
Does 4K footage use four times the storage of 1080p?
Roughly, yes — 4K has four times the pixels and typically runs at around four times the bitrate. It only pays off where you need to identify faces or plates at distance, like a driveway or long garden. For a porch or hallway, 1080p is plenty.
What size microSD card do most UK households need?
For one or two motion-only 1080p cameras, 128 GB per camera comfortably holds two to four weeks. Go 256 GB for 2K cameras or busier streets. Buy high-endurance cards — standard cards wear out under constant rewriting.