VoIP

How Much Bandwidth Does VoIP Really Need? A Simple Way to Calculate

"Is our internet fast enough for VoIP?" is the most common pre-sales question we get — and the honest answer is that raw speed is rarely the problem. Here's the simple math, and the parts that matter more.

The per-call math

A single VoIP call using the standard high-quality codec (G.711) consumes roughly 85–100 Kbps in each direction, including overhead. Compressed codecs use less. Practical planning number: 100 Kbps per simultaneous call, up and down.

So ten simultaneous calls need about 1 Mbps. Even a modest 100 Mbps business connection has bandwidth for hundreds of calls — on paper.

Why upload is the number that matters

Many broadband products are asymmetrical: fast down, slow up. Your voice leaves the building on the upload side, sharing it with email attachments, cloud backups, and video calls. When sizing a connection, look at the upload figure and what else competes for it.

The three numbers that matter more than speed

• Latency: the round-trip delay. Under ~150 ms one-way keeps conversation natural.
• Jitter: variation in packet timing. High jitter makes audio choppy even on fast connections. Under 30 ms is the target.
• Packet loss: even 1% loss is audible on a call that a file download wouldn't notice.

A cheap fast connection with high jitter will sound worse than a modest connection with clean metrics.

QoS: the setting that saves the day

The real-world cause of most bad audio isn't insufficient bandwidth — it's voice packets stuck behind a big upload. Quality of Service configuration on a business-grade router puts voice first in line, making the whole question of "enough bandwidth" mostly moot for typical offices.

Get measured, not guessed

Our free assessment measures your actual latency, jitter, and loss, counts your realistic simultaneous calls, and tells you whether your current connection is VoIP-ready — before you commit to anything.