Wirebook › Glossary › Bandwidth
What is bandwidth?
In one sentence: The most data a connection can carry each second, like the number of lanes on a road; internet plans are sold by it in Mbps.
A little more
Bandwidth is how much data a connection can carry each second, at most. Internet plans are sold by it, in megabits per second (Mbps). A bit is a tiny on-or-off signal, and eight of them make one byte, which is why a 100 Mbps line downloads at about 12 megabytes a second.
More bandwidth lets more things happen at once: several videos, a game download and a video call together. It doesn't make a single message arrive sooner; that waiting time is latency.
It's a bit like… How wide a road is: more lanes let more cars travel at once, but each car still drives at the same speed.
See it in action
- BonusWhy does every speed test give a different answer?A speed test is a water-balloon race: fill a balloon from the internet tap for ten seconds and divide the water by the time.9 min · interactive
- BonusWhy does a video call go blurry when the connection is slow?Dial a pretend video call's bandwidth thinner, spend a tiny 10-bit budget on eyes vs mouth vs wallpaper to still read a facial expression, then reveal the clear face.7 min · interactive
- 1What happens when you open a web page?Follow one click from your keyboard to a server and back: DNS, the padlock handshake, HTTP, tunnels and painting the page.6 min · interactive
- BonusWhy does the video call freeze when you walk to the kitchen?A phone holds one Wi-Fi box's baton at a time, and the phone decides when to pass it on.7 min · interactive
- BonusWhy does the internet slow down in the evening?Picture the internet as water: your house's pipe, one shared pipe under the street and a big main from far away.9 min · interactive
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