Broadband slower than advertised? How to check
A speed test measures what one device achieved at one moment. An advertised speed, an expected speed and a contractual minimum can mean different things.
Synthetic speed comparison
Invented example: three wired download tests over three days. The advertised plan speed is a reference, not a contractual minimum.
| Observation | Speed |
|---|---|
| Advertised plan | 200 |
| 1 | 48 |
| 2 | 52 |
| 3 | 50 |
What to check
Find the exact plan wording and repeat tests on the same device and server at different times. Record whether you used Wi-Fi or Ethernet and whether a VPN or other downloads were active. A wired test can help isolate the local wireless connection.
What to do next
Share dates, results and the plan wording with your provider. Ask it to investigate and explain its test method. A low result alone does not establish a breach.
Official source
Ofcom: broadband and Wi-Fi help
Sources checked 3 November 2026. Rules, contracts and complaint routes can change. Check official guidance for your circumstances.
Get help with your report
Send us a reviewed Kilobat support report. We can help you understand the measurements, choose a next test and prepare a message for your provider.
Slower than advertised · Wi-Fi and Ethernet · Packet loss and latency · Complaint letter · Rights updates