Broadband is sold in megabits per second, but what you feel is a mixture of several numbers: how fast data comes down, how fast it goes up, how long a round trip takes, and how steady that is. Run our internet speed test and you’ll get all four. Here’s how to read them.
Mbps vs MB/s
The most common source of confusion:
- Mbps = megabits per second. Used by ISPs and speed tests.
- MB/s = megabytes per second. Used by browsers, Steam and file managers when downloading.
- 1 byte = 8 bits, so divide by 8.
| Plan | Theoretical max download | 5 GB game download (best case) |
|---|---|---|
| 50 Mbps | 6.25 MB/s | ~13.3 minutes |
| 100 Mbps | 12.5 MB/s | ~6.7 minutes |
| 500 Mbps | 62.5 MB/s | ~1.3 minutes |
| 1 Gbps (1,000 Mbps) | 125 MB/s | ~40 seconds |
(5 GB = 40,000 megabits; at 100 Mbps that’s 400 seconds.) Real downloads are a little slower because of protocol overhead and the server’s own speed.
The four numbers in a speed test
Download
How fast data reaches you: streaming, browsing, downloads. This is the headline figure on your bill.
Upload
How fast you send data: video calls, cloud backups, posting videos, gaming voice chat. Many cable and ADSL plans have much lower upload than download (e.g. 500/50). Full-fibre plans are often symmetrical or close to it. If you work from home or upload large files, upload matters more than people think.
Ping (latency)
The round-trip time in milliseconds for a small packet to reach a server and come back. It decides how responsive things feel: games, video calls, even web browsing. Typical values: fibre 5–20 ms to a nearby server, 4G/5G 20–60 ms, traditional geostationary satellite 600 ms+ (low-orbit satellite services are far lower).
Jitter
How much the ping varies from moment to moment. High jitter causes choppy calls and rubber-banding in games even when average ping looks fine. Under about 10 ms is good; consistently above 30 ms is noticeable on calls.
How much speed do you need?
Rough per-activity figures:
| Activity | Download per user/stream | What else matters |
|---|---|---|
| Web, email, social | 5–10 Mbps | Low latency |
| HD video (Netflix 1080p) | 5 Mbps | — |
| 4K streaming | 15 Mbps (Netflix’s recommendation) | Stable connection |
| Video calls (Zoom/Teams HD) | ~3–4 Mbps down and up | Upload, low jitter |
| Online gaming | 5–25 Mbps | Ping and jitter far more than bandwidth |
| Large downloads, cloud backup | As much as possible | Upload for backups |
Add up simultaneous use. A family with two people streaming 4K (30 Mbps), one on a work video call (4 Mbps) and phones in the background might peak around 50 Mbps. A plan of 100 Mbps gives comfortable headroom; 500 Mbps–1 Gbps mainly helps with very large downloads and households with many heavy users.
For reference, the US FCC raised its definition of broadband to 100 Mbps down / 20 Mbps up in 2024.
Why your results vary
- Wi-Fi vs cable: Wi-Fi is often the bottleneck. Walls, distance, neighbours’ networks and older devices can halve your speed or worse.
- Device limits: an old laptop with Wi-Fi 4 (802.11n) or a 100 Mbps Ethernet port can’t reach gigabit speeds.
- Peak hours: evenings are busier, both on your ISP’s network and on popular servers.
- Test server: speed tests choose a nearby server; a distant or busy server reports lower numbers.
- Background traffic: cloud sync, updates, other people streaming in the house.
- VPN: adds encryption overhead and routes traffic further away, increasing ping.
To find out what your ISP is actually delivering, test by Ethernet cable directly from the router, with other devices idle, several times at different hours. Our what is my IP page shows which ISP and public IP address your connection is using, which is handy if you’re unsure whether a VPN is active.
How to fix slow Wi-Fi
- Restart the router and modem. Unexciting but often effective.
- Move the router: central, elevated, in the open, away from microwaves, fish tanks and thick walls. Not in a cupboard.
- Use 5 GHz or 6 GHz for nearby devices (faster, less interference) and 2.4 GHz for range.
- Change the channel if neighbours crowd yours; many routers do this automatically.
- Upgrade old hardware: a Wi-Fi 6 or 6E router (or Wi-Fi 7) makes a big difference with many devices.
- Add a mesh system for larger homes instead of cheap range extenders, which often halve throughput.
- Use Ethernet or powerline adapters for consoles, desktop PCs and TVs that don’t move.
- Check for bandwidth hogs: cloud backups and game updates can saturate the upload and spike ping for everyone.
When to contact your ISP
If wired speed tests are consistently far below your plan’s minimum guaranteed speed, gather evidence: several Ethernet results at different times with dates. In the UK, many providers have signed Ofcom’s voluntary broadband speeds code, which gives you a right to exit without penalty if speeds stay below the minimum guaranteed figure and the provider can’t fix it. In the US, check your contract and the FCC broadband label the provider must show for its plans.
Checklist
- Know whether you’re reading Mbps or MB/s.
- Test by cable, then by Wi-Fi, to separate line problems from Wi-Fi problems.
- Look at ping and jitter, not just download, for calls and gaming.
- Size your plan for simultaneous use, with some headroom.
- Fix placement, band and hardware before paying for a faster plan.