PC internet problems?
Call frozen again? Game lagging? Pick what's going wrong and we'll help you work out what to check first.
Fast internet can still feel slow.
A big download number feels reassuring. Calls and games also need quick, steady responses while someone else is downloading or backing up their photos.
- Capacity
- How much data can move.
- Responsiveness
- How quickly messages get through, idle or busy.
- Consistency
- How evenly responses arrive.
Our check measures your connection to Cloudflare. Your call or game can take a different route, so its own statistics help fill in the picture.
Start with what's going wrong.
No test needed to get started. Choose a guide for things you can look at now, then try one change at a time.
Want a hand checking your PC?
An AI agent can run checks on your PC and explain the readings as you go. See how that worked for slow browsing and choppy Teams calls across three Wi-Fi networks.
See AI troubleshooting in actionAsk your AI agent
"Use internet-diagnostics. My game lags, but my speed test looks good. Explain each test and guide me one step at a time."
Use the internet-diagnostics skill with a local AI agent such as Codex, Claude Code, Cursor, or Copilot. Read each command before approving it. Sometimes the checks leave the cause unresolved.
Both say 200 Mbps.
One keeps you waiting.
Here's a made-up example. Both connections estimate 200 Mbps download, but one takes much longer to respond while uploading.
Connection A
Connection B
Compare all example readings
| Reading | Connection A | Connection B |
|---|---|---|
| Estimated download | 200 Mbps | 200 Mbps |
| Idle response | 20 ms | 20 ms |
| Response during upload | 180 ms | 35 ms |
| Added median delay | 160 ms | 15 ms |
How that might feel
Connection A may feel sluggish during an upload. A backup could leave your game waiting even when there's plenty of download capacity.
What to try next
Pause other uploads and repeat the same profile on the same device. If added delay stays high, compare Ethernet. The check creates traffic itself, so pausing other transfers may leave the pattern unchanged.
How far these numbers get us
We still can't tell where the delay builds up, blame the provider, or describe a particular app's route. Neither example includes a packet-loss reading.
Learn how to investigate delay under loadPut your connection to the test.
See how quickly your connection responds, estimate transfer speeds, and watch what happens when it gets busy. Use the readings to pick one change, then check again.
Before you start
- Wait until calls or games have finished. Test traffic can interrupt them.
- Keep this tab visible and note whether other people or devices are using the connection.
- Use the same device and profile for comparisons. Save each result link and record what you changed.
Full check includes upload and a relay delivery check. Lower data uses smaller downloads and skips those stages. Both estimate speed during this check. Neither measures your line's maximum speed.
How measurements and ratings workNo account. Ready when you are.
Does your connection stay responsive when busy?
Download, upload, response time, packet delivery, and how your connection handles pressure.
Budget about 192 MB including estimated overhead, not a hard cap. Larger rounds may be skipped.
This check creates traffic and may briefly disrupt calls, games, or other people using your connection.
Test traffic goes to Cloudflare. Data use & privacy