What Is Packet Loss and How to Fix It

What is packet loss and how to fix it? Packet loss means some data packets never reach their destination; compare repeated tests to your router and an internet destination, then fix the first segment where loss appears. Loqmi’s speed test can show performance changes, but it cannot measure packet loss by itself.

What is packet loss and how to fix it

Your device sends calls, pages, and games as packets. Packet loss is the share of those packets that never arrives. Downloads may pause while the missing data is resent. A live call can sound clipped, because late audio is no longer useful to anyone.

Internet Protocol (IP) is best effort. It does not promise delivery, as described in RFC 1122. Think of it as a postcard service: it sends the card and hopes for the best. Transmission Control Protocol (TCP), common for web pages and file transfers, detects and retransmits missing data under RFC 9293. User Datagram Protocol (UDP), often used for interactive traffic, has no built-in recovery, so apps may add their own, as RFC 768 specifies. A fast download can still come with choppy voice. The network is not a hotel concierge.

Packet loss is not the same as speed, latency, or jitter. Speed is how much data can move in a given time. Latency is how long a packet takes to make a round trip, and jitter is how much that delay varies. Congestion can raise latency and cause drops at the same time, but one measurement cannot stand in for the others.

Test for loss without misreading the result

Reproduce the problem first, so you have something to compare. Note the time, the device, Wi-Fi or Ethernet, and whether someone is uploading or downloading. Run Loqmi’s browser speed test as a before-and-after snapshot, then use repeated ping tests for delivery evidence. A speed test measures throughput under its own conditions. It is not a packet-loss meter.

1. Find your default gateway (usually the router address listed in your device’s network details) and ping it repeatedly. On Windows, run ping /n 100 <gateway>. On macOS or Linux, run ping -c 100 <gateway>.
2. Run the same kind of test against a public IP or hostname, then against the affected service if it answers ping. Keep the target and sample length the same each time.
3. Repeat the test over Ethernet if you can, or stand close to the router on Wi-Fi. Test again while the problem is happening, then again during a quiet period.
4. Compare the sent and received counts. For example, 2 missing replies out of 100 is 2% observed probe loss for that test. That is not a severity grade, and it does not prove that every app loses the same share.

Ping sends Internet Control Message Protocol (ICMP) echo requests; see Microsoft’s ping reference. A router may deprioritize its replies while forwarding traffic, so a timeout is a clue, not a verdict. Windows pathping /n <target> measures along the route. Microsoft’s pathping guide distinguishes loss at a router from loss on a link. Treat isolated middle-hop loss cautiously when later hops respond normally.

Locate the first failing link

Think of the route as a chain: device, local link, router, modem or fiber terminal, provider network, then the service. The first hop is your local gateway. If tests to it fail, check Wi-Fi, the device adapter, the Ethernet cable, or the router. If the gateway stays responsive but several outside destinations lose replies, investigate the modem, provider access line, or wider route. If only one service is affected, the trouble may be beyond your home network.

Watch the pattern, not just the percentage. Repeated loss on one device but not another points toward that device or its connection. Loss that appears only during busy uploads suggests queueing or congestion, so pause cloud backups and large transfers, then compare again. A trace can show where the path changes, but routes can be asymmetric and routers may limit diagnostic replies. Troubleshooting has a few dramatic warning lights, and some are just routers that would rather not explain themselves.

Do not change DNS as a packet-loss fix. The Domain Name System (DNS) translates names into addresses. It does not repair dropped packets on a connection that is already open. Changing your IP address, buying a faster plan, or turning on a virtual private network (VPN) is not a general fix either. A VPN can change the route to one service, but it cannot mend a loose cable or a weak Wi-Fi hop. For those separate jobs, see our guides to changing DNS servers and checking whether a VPN is working.

Fix the cause in a low-risk order

1. Separate Wi-Fi from the rest. Move closer to the router and repeat the test in the affected room. If possible, use Ethernet as a control. Wi-Fi bars are basically a mood ring for radio signal: they show signal strength, not the health of the whole internet route. Reposition the router in an open, central spot, and keep it out of cabinets or behind dense furniture. If only one device is affected, reconnect Wi-Fi and check for an operating-system or network-adapter update.
2. Check cables and power. Reseat Ethernet connections and try a known-good cable or another router port. Check that the modem’s provider cable is firmly connected. Don’t open provider equipment; its status lights and diagnostics are enough to start.
3. Reduce load and restart once. Pause backups, large uploads, game downloads, and other heavy traffic. If the link improves, the issue may be congestion or a router struggling with queues. Restart the modem and router using their maker’s instructions, then compare the same tests again. A reboot works like a reset button for a moment, not a maintenance plan.
4. Update carefully. Check the router maker’s support page for firmware for your exact model and follow its update instructions. Do not interrupt an update, and do not install firmware meant for a similar-looking model. Avoid a factory reset unless support recommends it and you have the setup details needed to reconnect.
5. Escalate with evidence. If wired tests still show repeated loss to more than one outside destination, contact your internet service provider (ISP). Give them dates and times, affected devices, whether Ethernet was used, gateway and outside test results, and any modem event details they request. Ask them to check the line and service signal rather than insisting that one middle router is at fault.

When the test shows no loss

A clean ping sample does not prove that every app path is clean. Loss may be intermittent, directional, or limited to one server. Repeat the test during the failure and compare destinations. If the app reports loss, save that display and check its service status, because its traffic may take a different route from your ping.

If one website fails, check other sites and consider name resolution separately. If calls fail while browsing works, test during the call. When Wi-Fi looks responsible, our guide to logging into your router can help you find settings. Change one setting at a time and record the original value.