What is packet loss?
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Data travels across the internet in small chunks called packets. Packet loss is the share of packets that are sent but never arrive. It is shown as a percentage, and the ideal is zero.
Why it matters
For downloads, web pages and streaming, lost packets are simply sent again. You might see things slow down slightly, but nothing breaks. Real-time apps can’t wait for a resend:
- Video and voice calls drop syllables, freeze or go blocky.
- Online games show rubber-banding, missed hits and characters that teleport.
- Remote desktops stutter and lag behind your input.
How much packet loss is acceptable?
| Packet loss | Effect | HowFast gaming rating |
|---|---|---|
| Under 0.5% | Not noticeable | Great |
| 0.5% to 1% | Occasional glitches in games and calls | Good |
| Over 1% to 2.5% | Frequent glitches | Fair |
| Over 2.5% | Calls and games become hard to use | Poor |
Packet loss on HowFast today
Browsers can’t send the low-level messages that tools like ping use. To measure packet loss from a web page, a speed test needs a relay server (called TURN) that bounces small UDP messages back to your browser, and counts how many make the round trip:
packet loss = (messages sent − messages received) ÷ messages sent
That relay is not switched on yet, so the Packet loss tile currently reads Not available. We don’t estimate it or show a placeholder number. Because packet loss is optional in the gaming rating, gaming is rated without it and capped at Good, with the note “Packet loss not measured”. See the methodology page.
What causes packet loss
- Weak or congested Wi-Fi. The most common cause at home. Interference and distance cause wireless packets to be dropped.
- Faulty cables, connectors or ports. A damaged Ethernet cable or loose coaxial connector can drop packets constantly.
- Overloaded routers. Old or underpowered routers drop packets when many devices are busy.
- Line problems. Noise on DSL lines, or signal problems on cable, often show as loss that gets worse in wet weather or at busy times.
- Congestion further away, in your provider’s network or on the route to a particular game or service.
- Mobile signal. Weak cellular signal causes loss that changes as you move.
How to check and fix it
- Test on a cable. If the problem disappears, Wi-Fi is the cause: move closer to the router, change the Wi-Fi channel or band, or add a mesh point.
- Swap cables and ports. Try a different Ethernet cable and router port. Check that coaxial and phone connectors are tight.
- Restart the modem and router. It clears temporary faults, though it won’t fix a failing device.
- Look for a pattern. Note the time of day and what else was happening. Loss only in the evening points to congestion; loss in the rain points to the line.
- Contact your provider if loss continues on a cable connection with your own equipment ruled out. Most providers can check line quality remotely.
Until HowFast’s packet loss measurement is switched on, symptoms like choppy calls with good speed and low jitter are a strong hint of loss. Your operating system’s ping command (for example ping -n 100 on Windows or ping -c 100 on Mac and Linux) reports loss to any server you choose.
Frequently asked questions
Can I have packet loss with a fast connection?
Yes. Speed and loss are separate. A fast connection with even 1–2% loss can make calls and games worse than a slower one with none.
Is 0% packet loss possible?
Yes. A healthy wired connection should show 0% almost all the time. Occasional tiny amounts are normal on Wi-Fi and mobile.