Key Takeaways
- Bandwidth is the capacity of a connection: how much data it can move per second.
- It is measured in bits per second - Kbps, Mbps, Gbps. Note bits (b), not bytes (B): 8 bits make a byte.
- Throughput is what you actually get; latency is how long each trip takes. A wide pipe can still be slow if latency is high.
- Text chat needs almost no bandwidth; video calls need the most.
What Is Bandwidth?
Bandwidth is the maximum amount of data a network connection can carry in a set amount of time. Think of it as the width of a pipe: a wider pipe can move more water at once. It is measured in bits per second - kilobits (Kbps), megabits (Mbps) or gigabits (Gbps). A 100 Mbps connection can move at most 100 million bits, or 12.5 megabytes, every second.
Bandwidth vs Throughput vs Latency
| Term | What it measures | Unit |
|---|---|---|
| Bandwidth | The most data the link can carry | Mbps |
| Throughput | The data actually delivered, after congestion and loss | Mbps |
| Latency | How long one piece of data takes to arrive | Milliseconds |
A connection with plenty of bandwidth can still feel slow if latency is high - every message waits for the round trip. Real-time apps such as chat and calls care about latency at least as much as bandwidth.
How Much Bandwidth Do Chat and Calls Need?
- Text chat and chatbots: a few kilobytes per message - a website chat widget works on almost any connection once loaded.
- Voice calls: tens of kilobits per second per participant.
- Video calls: from a few hundred Kbps for small video to several Mbps for HD, per stream.
Video apps adjust quality to the bandwidth they measure, using techniques such as transport-wide congestion control. Persistent chat connections usually run over a WebSocket, which keeps overhead per message small.
Frequently Asked Questions
What is bandwidth in simple terms?
Is bandwidth the same as internet speed?
What is the difference between Mbps and MBps?
What is the difference between bandwidth and latency?
How much bandwidth does a chatbot need?
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