How much bandwidth does a VoIP call use?
A standard business VoIP call uses around 100 kbps in each direction, including network overheads. That’s a tiny fraction of a typical broadband connection - a single HD video stream uses many times more.
How to work out the speed your business needs
Multiply the number of calls you might have at the same time by 0.1 Mbps, then add headroom for everything else your team does online.
| Calls at the same time | Voice bandwidth needed (each way) |
|---|---|
| 5 | About 0.5 Mbps |
| 10 | About 1 Mbps |
| 25 | About 2.5 Mbps |
| 50 | About 5 Mbps |
Remember that the same connection also carries email, cloud files, video meetings and backups. A busy office should have plenty of spare upload capacity.
Why upload speed matters
Many broadband packages advertise high download speeds but much lower upload. VoIP sends your voice up the line just as much as it receives, so a weak upload speed - especially when someone is uploading large files - is a common cause of choppy calls.
What else affects VoIP call quality?
- Latency and jitter. Delays and uneven data flow cause echo and robotic audio. Business-grade connections keep these low.
- Wi-Fi. Wired desk phones are more reliable than Wi-Fi for heavy call users.
- Router settings. Quality of Service (QoS) gives voice traffic priority over downloads.
- Connection type. Full fibre and leased lines give the most consistent performance.
What type of connection is best for VoIP?
For small offices, full fibre or SoGEA broadband is usually plenty. Larger or call-heavy teams benefit from a leased line, which gives guaranteed, symmetrical speeds. Adding a 4G or 5G backup keeps your phones working if your main line drops. We offer business broadband from £25 a month and leased lines from £235 a month. See business broadband →
How to test your connection for VoIP
Run a speed test at your busiest time of day and note the upload speed, ping (latency) and jitter. If you’re unsure what the results mean, we can review them as part of a free IT & telecoms health check.