Bandwidth, speed, throughput — untangled
Bandwidth is capacity: the most your line can carry per second, like the width of a motorway. Throughput is what actually gets through during a real transfer. Speed is the colloquial umbrella for both. This test measures throughput under ideal, multi-connection load — the closest practical stand-in for your true bandwidth.
And latency is none of these: it’s how long each individual packet travels. A wide line can still feel sluggish if latency is poor — which is why this test measures both at once.
Mbps vs MB/s — the eight-times confusion
Network capacity is quoted in megabits per second (Mbps); files are sized in megabytes (MB). Eight bits make a byte, so divide by eight: a 400 Mbps line moves at most 50 MB each second. A “slow” 50 MB/s download on that line is actually perfection.
You can switch this site’s unit between Mbps and MB/s in the settings (gear icon) — the measurement is identical either way.
How much bandwidth do you actually use?
Less than the marketing suggests, until everything happens at once. A 4K stream takes ~25 Mbps, an HD call ~4, music ~1, browsing spikes briefly. The moments that saturate a line are big downloads, cloud backups — and the evening when all of it overlaps.
Bandwidth planning is about those overlaps: add up your household’s worst simultaneous half-hour and leave headroom. Our speed calculator does exactly that arithmetic for you.
Common questions
Is a bandwidth test different from a speed test?
In practice, no — both measure how much data your line moves per second. “Bandwidth” emphasizes capacity, and this page measures it the same way our full test does: several parallel streams, sustained for seconds, both directions.
How much bandwidth do I need?
Sum your busiest simultaneous moment: ~25 Mbps per 4K stream, ~8 per HD stream, ~4 per video call, ~3 per gamer, plus a browsing baseline — then add headroom. For a typical streaming family that lands between 100 and 300 Mbps. Our calculator does it per household.
Why does my bandwidth differ from what I pay for?
Wi-Fi, sharing, and time of day. Plans quote the line’s provisioned maximum, measured wired and idle. Test on a cable at a quiet hour to compare against your plan; test where you sit to see your daily reality.
What uses the most bandwidth at home?
Video, in every form — 4K streaming, video calls, camera uploads. Then game and OS downloads, which grab everything available while they run. Smart-home gadgets and music barely register by comparison.