Buying cameras, an NVR or microSD cards? This free security camera storage calculator shows how much storage you need for the number of days you want to keep, or how long the drive you already have will last. Adjust resolution, compression, frame rate and recording mode to match your setup.
Security Camera Storage Calculator
Find out how much hard drive or microSD space your cameras need, or how many days your storage will last.
100% = continuous. Motion-only is often 10–40% depending on activity.
Auto-estimated from your choices. Enter the exact value from your camera settings for the best result.
Estimates only. Real bitrates vary by camera, scene detail, night vision and settings. Tool by techhomejournal.com
How the Calculator Works
Storage depends mostly on the bitrate, the amount of video data each camera sends every second. The calculator uses this simple formula:
- GB per day per camera = bitrate in Mbps × 10.8 × share of the day recorded
- Total storage = GB per day × number of cameras × days to keep
The 10.8 comes from 86,400 seconds in a day divided by 8 bits per byte and 1,000 MB per GB. Hard drives also show slightly less usable space than the label, so the calculator allows about 7% for formatting when it suggests a drive size.
Typical Bitrates Used in the Estimate
When you pick a resolution, the tool fills in a typical bitrate. These are starting points; real cameras vary a lot with scene detail, night vision and settings.
| Resolution | H.264 (15 fps) | H.265 (15 fps) |
|---|---|---|
| 1080p (2MP) | about 4 Mbps | about 2.2 Mbps |
| 2K (4MP) | about 6 Mbps | about 3.3 Mbps |
| 5MP | about 8 Mbps | about 4.4 Mbps |
| 4K (8MP) | about 12 Mbps | about 6.6 Mbps |
For the most accurate result, open your camera or NVR settings, find the “bitrate” for the main stream, and type that number into the calculator.
Example: 4 Cameras for 30 Days
Four 2K cameras using H.265 at 15 fps (about 3.3 Mbps each), recording 24/7, use roughly 36GB per camera per day, or about 143GB a day in total. Keeping 30 days needs about 4.3TB, so a 6TB surveillance drive is the sensible choice. Switch to motion-only recording at 30% of the day and the same setup needs only about 1.3TB.
Tips to Save Storage
- Use H.265 (or H.265+) if your cameras and recorder support it. It typically needs much less space than H.264 for similar quality.
- Record motion or smart events on low-traffic cameras and keep 24/7 only for key areas like the front door.
- Lower the frame rate to 10–15 fps. That’s plenty for most home security footage.
- Use the sub-stream for continuous recording and the main stream for events, if your NVR supports dual-stream recording.
- Use surveillance-rated hard drives and high-endurance microSD cards, which are built for constant writing.
microSD Card or NVR?
A microSD card in each camera is simple and cheap for one to three cameras, especially with motion recording. For four or more cameras or 24/7 recording, an NVR with a hard drive is easier to manage and keeps footage safe indoors. Learn more in our guide to security cameras without subscription and our PoE home security camera system guide.
Frequently Asked Questions
How much storage does a security camera use per day?
A 1080p camera recording 24/7 at around 2–4 Mbps uses roughly 22–43GB a day. 4K cameras can use 70GB or more. Motion-only recording uses far less.
How many days will a 2TB drive record?
With four 2K cameras on H.265 recording 24/7 (about 3.3 Mbps each), a 2TB drive lasts about 13 days. With motion-only recording it can last several weeks.
Is 128GB enough for a security camera?
For one camera recording motion clips, often yes, for a week or more. For 24/7 recording at 2K, it lasts only a few days.
What happens when the storage is full?
Most cameras and NVRs use loop recording, which automatically overwrites the oldest footage. Make sure it’s turned on in your settings.
Does H.265 really save storage?
Yes. H.265 compresses video more efficiently than H.264, so it typically needs much less space for similar picture quality. Check that your camera, recorder and viewing app all support it.
