An NVR (network video recorder) is the box that receives video from IP cameras over a network, records it to hard drives and lets you watch it live or play it back. To choose one, match four numbers: channels (at least your camera count plus about 25% spare), incoming throughput (total camera bitrate plus 20%), drive bays and capacity (for your days of storage), and PoE ports if you want the cameras powered from the recorder. For example, 16 cameras at 4 MP and about 3 Mbps each need roughly 58 Mbps of NVR throughput and about 15.6 TB for 30 days of continuous recording. This guide gives the tables and the questions to ask before you buy.
PCBy the Pixl Canada install team. Calculated October 26, 2026. 8 min read.
- What an NVR does, in plain terms
- Channel and throughput tables
- Built-in PoE vs a separate switch
- A buyer’s checklist
- An NVR works with IP cameras. An analog system uses a DVR. See NVR vs DVR.
- Channels, throughput, drive capacity and PoE ports are the four specs that decide the fit.
- Choose a recorder that supports the codec your cameras use (H.265 saves storage) and open standards such as ONVIF.
- Plan for spare channels and drive bays so you can add cameras later.
What is an NVR?
NVR stands for network video recorder. IP cameras compress their own video and send it over Ethernet; the NVR receives each stream, writes it to hard drives and serves live view and playback to a screen, a phone app or a computer. It is the “brain and memory” of a wired camera system. Unlike a cloud camera, a local NVR keeps footage on your own premises. Compare the trade-offs in cloud storage vs local NVR.
How many channels do you need?
A channel is one camera input. Buy at least your camera count plus about 25% spare so you can add cameras without replacing the recorder.
| Cameras today | With about 25% spare | Common NVR size |
|---|---|---|
| 3 to 4 | 5 | 8 channels |
| 6 to 8 | 10 | 16 channels |
| 12 to 16 | 20 | 32 channels |
| 24 to 32 | 40 | 64 channels |
Recorders are sold in standard channel counts, so round up to the next size. See how many security cameras you need.
How much throughput does the NVR need?
Throughput is the total video bitrate the NVR can receive at once. Add up the bitrate of every camera and add 20% headroom. These planning bitrates assume H.265: about 2 Mbps for 2 MP, 3 Mbps for 4 MP and 6 Mbps for 8 MP (4K). Check your cameras’ real figures.
| Cameras | 2 MP | 4 MP | 8 MP (4K) |
|---|---|---|---|
| 8 | 16 (19) | 24 (29) | 48 (58) |
| 16 | 32 (38) | 48 (58) | 96 (115) |
| 32 | 64 (77) | 96 (115) | 192 (230) |
Recorders list “incoming bandwidth” or “max throughput” in their specs. A recorder with plenty of channels but low throughput cannot record all cameras at high resolution.
How many drive bays and what capacity?
Storage is bitrate multiplied by time: GB per day per camera is bitrate in Mbps multiplied by 10.8. Our business CCTV storage calculator has the full tables. For 16 cameras at 4 MP, 30 days of continuous recording is about 15.6 TB, which fits two 8 TB drives with little spare room and is more comfortably three or four drives.
| Spec | Why it matters |
|---|---|
| Number of bays | Decides how much total storage you can ever install |
| Maximum capacity per bay | Some recorders limit each drive to a certain size |
| RAID support | Keeps recording if one drive fails, at the cost of capacity |
| Surveillance-rated drives | Built for constant writing |
Should the NVR have built-in PoE ports?
| Option | Good for | Watch out for |
|---|---|---|
| NVR with built-in PoE ports | Small systems of 4 to 16 cameras close to the recorder | Total PoE budget, port count and cable length (100 m / 328 ft) |
| NVR plus a separate PoE switch | Larger systems, cameras spread across a site, or PTZ cameras | One more device to power and put on a UPS |
See PoE switch and UPS sizing and the CCTV cable guide.
NVR buyer’s checklist
| Check | What to look for |
|---|---|
| Channels | Your camera count plus about 25% |
| Throughput | Total camera bitrate plus 20% |
| Codec | H.265 support to save storage |
| Drives | Enough bays for your days of storage, plus surveillance-rated drives |
| Compatibility | ONVIF support, so you are not locked to one brand |
| Remote viewing | A phone app and a secure way to connect. See how to secure IP cameras |
| Power backup | A UPS for the NVR and switch |
| Warranty and support | Ask who services it. See warranty and support |
NVR guide: frequently asked questions
What is an NVR?
A network video recorder. It records video from IP cameras to hard drives and lets you watch live and playback.
How many channels do I need?
Your camera count plus about 25% spare, rounded up to the next standard size such as 8, 16, 32 or 64.
Can an NVR work without internet?
Yes. It records locally. Remote viewing from outside needs an internet connection. See cameras without internet.
Do all cameras work with all NVRs?
Not always. ONVIF support improves compatibility, but check the recorder’s supported camera list.
How much storage do I need?
16 cameras at 4 MP for 30 days of continuous recording need about 15.6 TB. See the storage calculator.
Does Pixl install and set up NVRs?
Yes. Wired CCTV gets a free written quote that lists cameras, recorder, storage and cabling separately. You pay after the job.
Get the recorder sized for your cameras
Send the camera count and photos of the site. Free written quote for wired CCTV. You pay after the job.
Business CCTV storage calculator
PoE switch and UPS sizing
What is CCTV?
How to set up an NVR
NVR not recording: fixes
Wired PoE or WiFi camera systems compared
Sources and method. Figures are calculated from the stated planning bitrates and are estimates, not measurements of one product. Check each recorder’s datasheet for real channel, throughput and capacity limits.
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.