Bandwidth, speed and throughput: what this test measures
Bandwidth is the maximum amount of data a connection can carry per second, measured in megabits per second (Mbps). Your plan's "speed" is in fact a bandwidth figure. What a test measures is throughput: the data that actually gets through at that moment, which is always a little lower because of protocol overhead, Wi-Fi and other devices sharing the line.
This test fills your connection for several seconds in each direction and reports:
- Download bandwidth: how much data you can receive per second (streaming, web pages, downloads).
- Upload bandwidth: how much you can send (video calls, cloud backups, live streaming).
- Ping, jitter and latency under load: how responsive the line stays while it is full.
How much bandwidth do you need?
| Use | Bandwidth needed per stream or device |
|---|---|
| HD video (1080p) | About 5 Mbps |
| 4K video | About 15 to 25 Mbps |
| Video call (HD) | 2 to 4 Mbps in each direction |
| Online gaming (the game itself) | Under 1 Mbps, but low ping |
| Downloading a 100 GB game | Over 2 hours at 100 Mbps, about 30 min at 500 Mbps |
| Cloud backup, live streaming | 10 to 50 Mbps of upload |
Add up what runs at the same time in your home and keep a margin of about 30%. Our bandwidth calculator does it in three questions.
Measure your connection now. Start the test
Why your bandwidth test is lower than your plan
- Wi-Fi: the most common cause. Test once over an Ethernet cable next to the router.
- Other devices: a backup, an update or a 4K stream elsewhere in the home takes part of the bandwidth. Find them with how to check bandwidth usage.
- A 100 Mbps port or old cable: a result stuck around 94 Mbps means the link is limited. See Ethernet cable categories.
- Peak hours: on cable and 5G, the bandwidth is shared with the neighbourhood. See internet slow in the evening.
- Throttling of some services: see how to check for throttling.
Test your provider's bandwidth
Our ISP speed test pages give the normal results for each provider and plan: Xfinity, Spectrum, AT&T Fiber, Verizon Fios, Frontier, Cox, WOW!, Astound, Sonic, BT, Virgin Media, NBN and more.
Frequently asked questions
What is a bandwidth test?
A bandwidth test measures how much data your internet connection can transfer per second, in download and upload. It is the same measurement as an internet speed test: bandwidth is the capacity, and the test shows how much of it you really get.
Is bandwidth the same as internet speed?
In everyday use, yes: providers sell bandwidth and call it speed. Strictly, bandwidth is the capacity of the link, while latency (ping) is how quickly data starts arriving. A connection can have high bandwidth and still feel slow if latency is high.
How much bandwidth do I need?
About 25 Mbps per person for HD streaming and browsing, 100 Mbps for a family that streams and works from home, and 300 Mbps or more for large households with several 4K screens.
Why is my upload bandwidth so much lower than my download?
Cable, DSL and most 5G connections give most of their capacity to download. Fibre plans are often symmetrical, with equal upload and download.
