What packet loss means and why it matters
Every piece of data you send or receive over the internet is broken into small units called packets. Each packet travels independently across the network and is reassembled at the destination. Packet loss occurs when one or more of these packets fail to arrive. The loss rate is expressed as a percentage of total packets sent.
Even small amounts of packet loss have outsized effects on user experience. At 1% loss, video calls begin showing pixelation and audio dropouts. At 2% to 3%, online gaming becomes frustrating with visible rubber-banding and missed inputs. Above 5%, web browsing slows noticeably as the browser must repeatedly request missing data, and streaming services struggle to maintain smooth playback.
Packet loss is fundamentally different from slow speed. A connection can have very high bandwidth but still suffer from packet loss due to a faulty cable, congested routing hardware, or wireless interference. This is why some users report that their internet feels broken despite their speed test showing high Mbps numbers — the speed test measures throughput, but the lost packets degrade real-time performance.
Common causes of packet loss
WiFi interference is the most common cause of packet loss in home networks. Physical obstacles (walls, floors, large furniture), electromagnetic noise from microwaves and baby monitors, and congested wireless channels all cause packets to be corrupted or lost during wireless transmission. Switching to a wired Ethernet connection eliminates WiFi-related packet loss entirely.
Faulty or degraded network hardware is the second most common cause. Old Ethernet cables (especially Cat5 or lower), damaged coaxial cables, and aging routers with failing components can all introduce packet loss. If you experience packet loss on a wired connection, try swapping the Ethernet cable first — it is the cheapest and easiest fix.
On the provider side, overloaded network equipment, misconfigured routing tables, and physical damage to the network infrastructure (such as cut fibres or water-damaged junction boxes) cause packet loss that you cannot fix locally. If wired packet loss persists after replacing your cables and router, the issue is almost certainly with your ISP.
Step-by-step fix for packet loss
Step 1: Run a speed test that measures packet loss (like InternetSpeedTest.fit) and note the percentage. Then switch from WiFi to a direct Ethernet connection and test again. If the packet loss disappears, the problem is your WiFi — adjust your router's position, switch to the 5 GHz band, and change to a less congested channel.
Step 2: If packet loss persists on Ethernet, replace the Ethernet cable with a new Cat6 or Cat6a cable and retest. Old or damaged cables are a surprisingly common source of intermittent packet loss that is difficult to diagnose without cable replacement.
Step 3: If packet loss continues with a new cable on a wired connection, the issue is either your router or your ISP. Restart your router and modem. If the problem persists after a full restart, connect your computer directly to the modem (bypassing the router) and test once more. If loss persists at the modem, contact your ISP — the fault is in their network and they need to dispatch a technician.