How Much Footage Does a 64GB SD Card Hold in a Security Camera?

In a battery security camera that records only when it detects motion, a 64GB card holds around 6 months of footage on average. We measured 333 motion recordings from three of our own Reolink cameras and the average clip was about 2 MB, so a 64GB card fits roughly 30,000 clips. How long that lasts depends almost entirely on how many times a day your camera is triggered.

Why the answer is in clips, not hours

Most charts online answer this question in hours of video, because they assume a camera recording all day. A battery camera doesn't do that. It wakes up, records a short clip and goes back to sleep, so the useful measure is how big each clip is and how many clips you get each day.

From our own measurements across 333 recordings:

• Average clip: about 2 MB
• 90% of clips: under 3.4 MB
• Largest clip: 7.3 MB

A 64GB card shows up as roughly 59GB of usable space once it's formatted, because card makers count a gigabyte slightly differently from cameras and computers. Divide that by 2 MB and you get about 30,000 average clips. If every clip were as big as our 90th-percentile figure of 3.4 MB, you'd still fit about 17,000.

Clip length matters too. Each clip runs for as long as the motion lasts, plus a post-record time after it stops. On Reolink Wi-Fi battery cameras that can be set to 8, 15 or 30 seconds, plug-in Wi-Fi and PoE cameras offer 15 seconds, 30 seconds or 1 minute, and the 4G Reolink Go is fixed at 10 seconds. A longer post-record time means bigger clips.

How many times a day does a security camera actually trigger?

Most people guess 10 to 15 times a day. Our real cameras were triggered between 34 and 135 times a day.

Every trigger counts, not just strangers: you leaving for work, the kids coming home, the cat, a delivery driver, cars going past, headlights at night, a plant moving in the wind, rain and insects. A camera on a terrace front that looks across a busy footpath in Newtown or Surry Hills will trigger far more often than one watching a back gate in a quiet lane.

Worked examples: quiet, busy and badly tuned cameras

The table below uses our 2 MB average clip and about 59GB of usable space. It assumes overwrite is on, so once the card is full the camera deletes the oldest clips to make room. The trigger counts all come from our own measurements.

The cobweb row is real. A web in front of one camera triggered it almost constantly: more than 9,000 recordings and nearly 1 TB in a few days. At that rate a 64GB card fills in hours, which means everything older than that morning has already been deleted.

So why do we say "around 6 months"?

A quiet camera does much better than 6 months, so why not quote that? Because trigger counts change through the year. Summer brings spiders and insects, windy weeks bring moving branches, and some nights the clips run longer. Around 6 months sits between our busy-camera figures, and it's a safer number to plan around than a best case.

The card also never "runs out". With overwrite on, the real question is how far back your footage goes on the day you need it.

Why continuous recording is completely different

Continuous (24/7) recording is a different job. The camera writes video every second of the day, so what matters is the bitrate, not the number of clips.

Reolink's own storage table gives these figures for a 64GB card recording around the clock (main stream only):

That's from Reolink's SD card recording guide, which also notes that the sub-stream bitrate adds to the total. So a 24/7 camera fills a 64GB card in roughly one to three days.

Most battery and solar cameras record only on motion. Reolink's storage guide says battery cameras don't support continuous recording, but its continuous recording set-up guide says some battery models do. If yours offers it and you turn it on, ignore the motion figures above and use the continuous table. Reolink's suggestions for making continuous recording last longer are a lower bitrate or a bigger card.

Why we fit a 64GB card as standard

When WireFree Security supplies Reolink cameras, each one gets a 64GB card. Here's why:

• It covers months of motion recording. If something happens, you'll usually want the footage within days, not months.
• It works in every Reolink camera with a card slot. Some older models, including the Argus 2, Argus Pro and the original Reolink Go 4G camera, only take cards up to 64GB. Many newer models take 128GB to 512GB.
• A bigger card doesn't fix the real weak point. The card sits inside the camera. If someone pulls the camera off the wall, the footage on it goes too. A 512GB card won't help with that, but an off-site copy will. That's why our supplied cameras come with 6 months of WireFree Cloud, which uploads each recording to storage in Sydney.

A bigger card does make sense for a plug-in camera recording 24/7, or for a business that wants a long history on the card. Whatever size you buy, Reolink's requirements are Class 10 or faster, formatted FAT32 (the camera can format it for you), and SDXC for anything over 32GB.

How to make a 64GB card last longer

These steps are roughly in order of how much difference they make.

1. Turn on person (and vehicle) detection. On one busy business driveway we measured, switching to person-only detection with a detection zone cut recordings by about 97%, from about 1,300 a day to under 40.
2. Draw a detection zone. Leave out the footpath, the road, the neighbour's yard and any plants that move. Only cover the area you actually care about.
3. Keep the lens clear of webs. One web can fill a card in hours. Our guide to fixing false alerts covers spiders, trees and sensitivity settings.
4. Shorten the post-record time. Dropping from 30 seconds to 15 makes each clip smaller. Leave enough time to see where someone goes after they leave the frame.
5. Turn the sensitivity down a notch before you lower the quality. Dropping the resolution saves space, but detail is what makes footage worth having.
6. Check overwrite is on. Some models, such as the Argus 2, Argus Pro and Reolink Go, overwrite automatically. On others, if "No Overwrite" is selected, the camera stops recording when the card is full. Some models also let you choose how many days to keep.
7. Save important clips straight away. Download them to your phone or keep them in the cloud before they get overwritten. If police or your insurer need a copy, see how to give CCTV footage to NSW Police or your insurer.

How to work out your own camera's figure

Your camera's figure will be different from ours, and it only takes a week to find out:

1. Write down how much card space is used today (it's in the camera's storage settings in the app).
2. After 7 days, check the storage used again and divide the increase by 7. That's your daily usage.
3. Divide your usable space (about 59GB, or 59,000 MB) by your daily usage. The answer is roughly how many days back your card goes.
4. While you're there, scroll through a day of playback and see what's triggering the camera.

Say your camera uses 300 MB a day. 59,000 ÷ 300 = about 197 days, or around 6 months. If you get a much smaller number, something is triggering the camera too often. Fix that before you buy a bigger card.

The short version

A 64GB card in a motion-recording battery camera holds around 6 months on average. A quiet camera holds a lot more, and a badly aimed camera or a cobweb can cut that to weeks or hours. Get the detection settings right first, keep the lens clear and save important clips somewhere other than the camera. If you're adding cameras, our installation prices include setting up motion zones and notifications.