CCTV Planning Tool · 05 of 10

Bandwidth Calculator

Find out how much network bandwidth your cameras need inside your building, and how much internet upload speed you actually need for remote viewing. Two very different numbers — most people get this wrong.

The two bandwidth numbers nobody explains

When people plan CCTV bandwidth, they add up all camera bitrates and assume that's their internet speed requirement. This is wrong — and it leads to either overspending on internet plans, or underestimating what the LAN switch needs to handle.

There are actually two bandwidth numbers, and they're often 10× different:

1. LAN bandwidth — all your cameras streaming to the NVR/recorder. This is huge (every camera contributes) but it never leaves your building. It needs a Gigabit switch, not internet speed.

2. Internet upload — only the streams sent OUT to remote viewers. This is tiny by comparison, especially with a substream. A few Mbps usually suffices.

A real example: 16 cameras, 4 MP, 15 fps, H.265.

• LAN bandwidth: ~38 Mbps — every camera continuously streams to the NVR. Needs a Gigabit switch.
• Internet upload with 2 remote viewers + substream: ~1 Mbps. Any internet plan handles this.

Notice: the internet upload is 40× smaller than the LAN bandwidth. Don't conflate the two.
LAN bandwidth
Inside your building
All cameras → NVR. Stays on your local network. Drives the switch + cable choice. Always equals all-cameras × bitrate.
Internet upload
Going to the cloud / remote
Only what's needed for remote viewers + cloud backup. Often a tiny fraction of LAN. Drives your ISP plan choice.
Main vs Sub stream
The biggest lever
Substream is a low-res copy of the video for live viewing. Cuts viewing bandwidth by ~80% with no impact on recording quality.

Calculate your bandwidth

Six settings. Live updates for both LAN and Internet sides.
All cameras feeding into the NVR / recorder.
H.265 (HEVC): the modern standard. ~40% smaller files than H.264 for the same quality.
Affects per-camera bitrate. 15 fps is the standard middle ground.
People watching live from outside your building (phone, browser, cloud app).
Substream: a low-res 1 MP @ 8 fps live preview. ~80% smaller than the main stream.
LAN bandwidth · cameras → NVR
— Mbps
Inside your building. Drives switch + cable choice.
LOCAL
Internet upload · for remote viewers
— Mbps
What your ISP upload plan must handle.
INTERNET
How the bandwidth flows

Does my network handle it?

LAN: required vs Gigabit Ethernet — of 1000 Mbps
—
Internet upload: required vs common plans — needed
—

Equipment & service recommendation

PoE switch
—
—
Internet upload plan
— Mbps
with 50% headroom
Per-camera bitrate (main)
— Mbps
—

Get this estimate as a PDF

A clean, branded report with both LAN and Internet bandwidth, network diagram, and recommended switch + ISP plan. Useful for sharing with your IT team or installer.