Is your connection dropping data?

What this test can and can’t tell you

Being straight about the method, because most browser-based “packet loss” tools aren’t: a browser cannot send real ICMP pings. What this does is fire 40 small uncached HTTP requests at our own endpoint and count how many fail or time out. That is a good proxy for a connection dropping data, but it is not the same measurement as a command-line ping, and it differs in two ways worth knowing:

• TCP hides loss. If a packet is dropped, TCP quietly re-sends it. The request still succeeds, just slower. So real loss often shows up here as a wider round-trip spread rather than a failed probe — which is why the spread figure is displayed next to the loss percentage.
• It measures the whole path. Your Wi-Fi, your router, your ISP and our host are all in the chain. A poor result tells you something in that path is dropping data, not specifically where.

For the definitive version, run ping -n 100 1.1.1.1 on Windows or ping -c 100 1.1.1.1 on macOS/Linux, which uses real ICMP and reports true loss. If this tool shows a problem, that’s the next step — and it’s the output worth sending to your ISP.

Why packet loss matters more than speed

Loss is the most under-diagnosed connection fault in South Africa, because it doesn’t show up on a speed test. A line can measure a perfect 200 Mbps and still be unusable for calls, because throughput is an average over seconds while a dropped packet is an instant gap. Video conferencing, gaming and VoIP all depend on packets arriving in order and on time, which is a different requirement from arriving quickly on average.

Rough thresholds: under 1% is normal and unnoticeable; 1–2.5% starts to affect calls; above 5% is a real fault. Loss also tends to arrive with jitter, so if you see a wide spread above, the latency & bufferbloat test will show whether the line degrades under load — a very common cause that looks like loss.

Common causes, in the order worth checking

1. Wi-Fi. By far the most common. Interference and weak signal drop frames constantly. Retest by cable, or use Wi-Fi or line? to separate the two.
2. A saturated line. If something is downloading in the background, loss is expected and isn’t a fault.
3. Bad cable or port. A damaged network cable between ONT and router produces exactly this symptom. Swap it — it’s the cheapest test you can run.
4. A failing ONT or router. Check the ONT lights; a marginal optical signal causes intermittent loss without fully dropping the line.
5. Upstream congestion. If it only happens in the evenings, that’s your ISP’s capacity, not your equipment — see why is my internet slow.

If loss is intermittent, one test won’t prove anything to a support desk. The uptime monitor logs over hours and exports a timestamped CSV, which is far harder to dismiss than a single screenshot.