A business security camera system recording 16 cameras at 4 MP continuously for 30 days needs about 15.6 TB of storage, and about 6.2 TB if it records only on motion 40% of the time. The formula is: storage in GB per day = bitrate in Mbps × 10.8, then multiply by the number of cameras and the days you keep. This page gives planning bitrates, ready-made tables for 4, 8, 16 and 32 cameras at 30, 60 and 90 days, and what to ask for in a quote. The numbers are planning estimates: your cameras’ real bitrate depends on the model, codec and scene.
PCBy the Pixl Canada install team. Calculated October 26, 2026. 7 min read.
- The formula and its assumptions in the open
- Tables for 4, 8, 16 and 32 cameras
- Continuous vs motion recording
- Free written quote for wired CCTV
- Storage = cameras × GB per day × days kept. One Mbps of video is 10.8 GB per day.
- Resolution and days kept matter most. Doubling the retention doubles the storage.
- Motion-only recording can cut storage a lot in quiet areas but little in busy ones.
- A formatted drive shows about 9% less than its label, and RAID uses extra capacity.
How do you calculate CCTV storage?
Video storage is bitrate multiplied by time. A camera recording at 1 Mbps writes 0.125 MB every second, which is 10.8 GB in 24 hours. So:
- GB per day per camera = bitrate in Mbps × 10.8
- Total TB = cameras × GB per day × days ÷ 1,000
These planning bitrates assume H.265 compression and continuous recording. Real bitrates vary by manufacturer, frame rate, scene motion and night mode, so check your camera’s datasheet or recorder before you buy drives.
| Camera resolution | Planning bitrate | GB per day | GB for 30 days |
|---|---|---|---|
| 2 MP (1080p) | 2 Mbps | 21.6 | 648 |
| 4 MP | 3 Mbps | 32.4 | 972 |
| 8 MP (4K) | 6 Mbps | 64.8 | 1,944 |
H.264 recorders use more space for the same picture, often around 40% more than H.265. If your recorder is older, plan for the higher figure.
How much storage do 4, 8, 16 and 32 cameras need?
| Cameras | 30 days | 60 days | 90 days |
|---|---|---|---|
| 4 | 3.9 TB | 7.8 TB | 11.7 TB |
| 8 | 7.8 TB | 15.6 TB | 23.3 TB |
| 16 | 15.6 TB | 31.1 TB | 46.7 TB |
| 32 | 31.1 TB | 62.2 TB | 93.3 TB |
| Resolution | Storage |
|---|---|
| 2 MP | 10.4 TB |
| 4 MP | 15.6 TB |
| 8 MP (4K) | 31.1 TB |
For how long businesses keep footage and why, see how long security cameras keep footage. For resolution trade-offs, see the 4K security camera guide.
How much does motion recording save?
Motion-only recording writes video only when something moves, so the saving depends on how busy the scene is. The percentages below are planning assumptions for illustration, not measurements.
| Recording mode | Share of the day recording | Storage | Typical use |
|---|---|---|---|
| Continuous | 100% | 15.6 TB | Entrances, tills, anywhere you cannot afford gaps |
| Motion, busy areas | about 70% | about 10.9 TB | Retail floors, reception |
| Motion, quiet areas | about 40% | about 6.2 TB | Back lanes, storage rooms, after hours |
| Motion, rarely active | about 20% | about 3.1 TB | Parking at night, unused rooms |
A common approach is continuous recording on key cameras (entrance, till, cash room) and motion recording on the rest. Say which cameras are which when you request a quote.
How do you choose the drives?
| Drive label | Shows as about |
|---|---|
| 4 TB | 3.6 TB |
| 8 TB | 7.3 TB |
| 12 TB | 10.9 TB |
| 16 TB | 14.6 TB |
| 20 TB | 18.2 TB |
- Allow headroom. Plan about 20% above your calculated figure so night mode and busier days do not shorten your retention.
- Use surveillance-rated drives. They are built for constant writing.
- Know your recorder’s limits. Each recorder supports a number of drive bays and a maximum capacity per drive. See NVR vs DVR.
- RAID uses extra capacity for redundancy. Ask whether the quote includes it.
What should you ask for in a CCTV quote about storage?
| Ask | Why |
|---|---|
| How many days at what resolution and recording mode? | A quote should state days of footage, not just drive size |
| Which codec does the recorder use? | H.265 needs noticeably less storage than H.264 |
| Is the storage RAID or a single drive? | A single drive failure loses footage |
| Can I export clips quickly? | You will need to hand footage to an insurer or the police |
| What happens when the drive is full? | Most recorders overwrite the oldest footage |
Pixl gives a free written quote for wired CCTV, itemized by cameras, recorder and storage, cabling and labour. See the business camera quote checklist and commercial CCTV installation cost.
Business CCTV storage: frequently asked questions
How much storage does a 16-camera system need for 30 days?
About 15.6 TB at 4 MP with continuous H.265 recording, and about 6.2 TB if it records on motion 40% of the time. These are planning estimates.
How do I calculate CCTV storage?
GB per day per camera = bitrate in Mbps × 10.8. Multiply by cameras and by days, then divide by 1,000 for TB.
Does 4K need much more storage than 4 MP?
On these planning bitrates, 8 MP (4K) needs about double a 4 MP camera and three times a 2 MP camera.
Does motion recording save storage?
Yes in quiet areas, less in busy ones. Many businesses record continuously on key cameras and on motion elsewhere.
How long should a business keep footage?
Many businesses keep about 30 days. Ask your insurer if they have a requirement, and say your target when you ask for a quote.
Does Pixl quote storage?
Yes. Wired CCTV gets a free written quote that lists the recorder and storage separately. You pay after the job.
Tell us the camera count and the days you need
We size the storage and quote it in writing. Free for wired CCTV. You pay after the job.
PoE switch and UPS sizing
How long cameras keep footage
NVR vs DVR
Small business WiFi, camera and TV package
Sources and method. All figures are calculated from the stated formula and planning bitrates, which are assumptions rather than measurements of any one product. Bitrate depends on the camera, codec, frame rate and scene. Check the datasheet for your cameras.
About Pixl Canada. Pixl Canada is an installation company based in Edmonton, Alberta, serving cities across Canada with TV mounting, security cameras, appliance installation and smart home setup. Call or text (587) 899-7495. Open Monday to Saturday 8am to 8pm and Sunday 9am to 7pm.