Cat6 Bandwidth Calculator

UsableThroughput(Mbps) = LinkRate × (1 − Overhead) × Utilization × EnvFactor

• LinkRate is chosen from common copper link speeds using channel length and cable grade.
• Overhead represents protocol and framing costs that reduce payload throughput.
• Utilization is the sustained load you allow for stable latency and retries.
• EnvFactor derates for installation realities: length, connectors, bundling, temperature, PoE heating, and shielding.

1. Choose the cabling grade and enter permanent link and patch lengths.
2. Enter connectors and bundle size to reflect your containment layout.
3. Set temperature and PoE level if cables carry power.
4. Provide utilization and overhead suitable for your network policy.
5. Enter streams, average stream rate, plus growth and redundancy margins.
6. Click calculate and review status, headroom, and recommendations.
7. Export CSV for schedules, or PDF for submittals and records.

1) Link rate versus usable throughput

Cat6 links are commonly commissioned at 1G, 2.5G, 5G, or 10G depending on channel length and site conditions. Payload throughput is lower than link rate because frames carry headers, interframe gaps, security tags, and occasional retransmissions. For CCTV, access control, Wi‑Fi backhaul, and BMS controllers, designing on usable throughput helps protect latency and avoids late-stage surprises.

2) Channel length and component count

The channel includes the permanent run plus patch cords on both ends. A 90 m permanent link with 10 m of patching effectively becomes a 100 m channel. Extra connector pairs add small losses and reflections that reduce margin for higher rates. Limiting unnecessary panels and using certified terminations improves predictability during commissioning.

3) Bundling, temperature, and PoE heating

Dense bundles can increase alien crosstalk and trap heat. As temperature rises, copper attenuation increases and headroom drops. If the link also carries power, cable temperature can rise further, especially with higher PoE classes. Coordinated tray fill, separation from noise sources, and suitable containment help maintain stable performance.

4) Converting devices into design demand

This calculator models demand as simultaneous streams multiplied by an average stream rate. For example, eight 18 Mbps streams create 144 Mbps base demand. Adding 10% redundancy and 25% growth produces a 198 Mbps design demand. Clear assumptions support scope control when device counts change. Use measured camera bitrates, not brochure peaks, and keep margin for firmware updates and higher resolutions over project life.

5) Using headroom to drive decisions

Headroom equals estimated usable throughput minus design demand. A healthy margin supports bursts, retries, and future expansions. If headroom is low, shorten runs, reduce bundle density, improve shielding and grounding, or upgrade to Cat6A or fiber for longer reach and resilience. Documenting inputs and margins supports approvals and maintenance.

1) What does “usable throughput” mean here?

It is estimated payload bandwidth after subtracting protocol overhead, applying your utilization target, and adding conservative derating for installation conditions such as length, connectors, bundling, temperature, and PoE.

2) Why can Cat6 show different link rates by length?

Higher speeds need more signal margin. Shorter channels typically support higher negotiated rates, while longer channels may step down to 5G, 2.5G, or 1G depending on equipment and conditions.

3) What utilization target is common for buildings?

Many teams plan around 60–80% sustained utilization for shared links. Lower targets help preserve latency and reduce packet loss when bursts and retransmissions occur.

4) How should I set average stream rate for CCTV?

Use the codec and resolution settings expected during operation, not marketing “max” numbers. If bitrate varies, use an average and keep redundancy and growth margins to cover peaks.

5) Does PoE always reduce bandwidth?

PoE mainly affects temperature. Warmer cables have slightly higher attenuation, which reduces margin. The effect is usually small, but it increases with higher power levels and large bundles.

6) Is shielding required for performance?

Not always. Good routing and separation often matter more. Shielding can help in noisy areas, but it must be terminated and grounded correctly to deliver benefits.

7) When should I upgrade to Cat6A or fiber?

Upgrade when channel length, noise exposure, or demand reduces headroom too much. Cat6A improves 10G reach, while fiber supports longer distances and strong EMI immunity.