Packet Loss Rating Guide

What Causes Packet Loss?

Network congestion — too many devices sharing a network segment causes routers to drop packets. Common on cable internet during peak hours (7–10 PM). Faulty hardware — damaged coaxial cable, loose ethernet, or aging router. Wi-Fi interference — competing signals, distance, or RF interference. ISP-side issues — congested nodes or equipment problems at the provider level.

How to Fix Packet Loss

Start by switching from Wi-Fi to ethernet. Restart your modem and router. Test directly from the modem (bypassing your router) to isolate home network vs ISP. If loss persists on a direct modem connection, call your ISP — they can check line quality, SNR, and node congestion.

How This Test Works — and What Makes It Different

Most packet loss tools are either desktop apps that require admin access, command-line tools using ICMP (which is often blocked by ISPs and firewalls), or third-party services that embed iframes. This tool runs entirely in your browser with no installation, no plugins, and no data sent to any third-party other than Cloudflare’s public speed test endpoint.

How the 50 probes work

50 sequential XHR GET requests are sent to speed.cloudflare.com/__down?bytes=0 — a zero-byte public endpoint. Each has a 4-second timeout. Requests that time out or return a network error are counted as lost. Results appear in real time as the visual packet grid fills in: green = delivered, red = lost.

HTTP vs ICMP packet loss

This test measures HTTP-layer packet loss — the same layer used by browsers, games, and video calls. The Windows pathping or ping -n 100 commands use ICMP, which many home routers and ISP devices process at a lower priority than real application traffic. ICMP tests can show 0% loss while your video calls drop packets regularly. HTTP-layer testing is closer to what your applications actually experience.

Why 50 probes? Fewer than 20 probes can easily miss intermittent packet loss. With 50 requests, even a single lost packet shows up as 2%, giving you a meaningful signal. Run the test 2–3 times to distinguish between a momentary blip and a persistent problem. Consistent loss across multiple runs is the sign to call your ISP.

Why Cloudflare? Cloudflare’s edge is geographically close to most users and is not affiliated with any ISP. Tests to ISP-owned servers can mask packet loss that happens specifically between your home and the rest of the internet — the segment your ISP controls but is not their own server farm.

How to Check Packet Loss on Mac

macOS includes a built-in ping tool in Terminal that lets you measure packet loss without installing anything. Here’s how to run it, read the output, and compare it to this browser-based test.

Method 1: Terminal ping command (built-in, free)

Open Terminal (Applications → Utilities → Terminal, or Spotlight search: Terminal). Type the following command and press Enter:

ping -c 100 8.8.8.8

This sends 100 ICMP packets to Google’s public DNS server. When it finishes, macOS prints a summary. The key line to read:

100 packets transmitted, 97 received, 3.0% packet loss

To test continuously for intermittent loss (useful for catching evening congestion), run ping -t 8.8.8.8 and press Ctrl+C after a few minutes. The percentage shown when you stop is your loss rate.

Method 2: Use this browser tool (no Terminal required)

The test at the top of this page measures HTTP-layer packet loss — the same layer your browser, video calls, and most apps operate on. It’s often more diagnostic than Terminal ping for real-world issues: ICMP (what ping uses) is sometimes deprioritised by ISP routing equipment. If Terminal shows 0% but the browser tool shows loss, the problem is at the application layer — run both for a complete picture.

Terminal ping vs. browser test — which is more accurate on Mac?

Activity Monitor tip: Open Activity Monitor (Applications → Utilities), click the Network tab, and watch “Packets In Errors” and “Packets Out Errors” for your Wi-Fi or Ethernet adapter while running the test. Errors climbing alongside packet loss point to a hardware or cable issue rather than ISP congestion.

Spectrum Packet Loss Test & Fix

Spectrum cable customers experiencing lag spikes, frozen video calls, or choppy gaming should run the test above before calling support. Packet loss on Spectrum is most commonly caused by an oversubscribed cable node, a deteriorating coaxial cable connection at the modem, or Wi-Fi interference. Each has a different fix.

Most common cause: cable node congestion (peak hours)

Spectrum uses hybrid fiber-coax (HFC) infrastructure — a shared medium where multiple homes in your neighborhood connect to the same cable node. When too many users are active simultaneously, the node becomes oversubscribed and starts dropping packets. Key sign: packet loss appears in the evening (7–10 PM) and clears up overnight.

Fix: Call Spectrum at (978) 723-5746 and report intermittent packet loss correlating with peak hours. Ask the agent to check node congestion and capacity at your node. Persistent reports from multiple customers in an area trigger a node split or capacity upgrade.

Step-by-step Spectrum packet loss diagnosis

Xfinity & Comcast Packet Loss Test & Fix

Xfinity (Comcast) cable customers are among the most likely to encounter packet loss — primarily because Xfinity’s 1.2 TB monthly data cap can trigger throttling near the limit, and cable node congestion is common in densely served Xfinity markets. Run the test above, then work through the causes below.

Xfinity-specific cause: data cap throttling near 1.2 TB

When your household approaches or exceeds Xfinity’s 1.2 TB monthly cap, Xfinity may throttle connection speeds — which can appear as elevated latency and intermittent packet loss in gaming and video calls. Check your usage in the Xfinity app (Account → Internet → Data Usage). If you’re within 100 GB of the cap, throttling may be your issue. Solutions: add the Unlimited Data Option ($30/mo) or add one Xfinity Mobile line (waives the cap for free).

Evening congestion on Xfinity cable

Like all cable ISPs, Xfinity uses shared HFC infrastructure. Evening congestion (7–10 PM) on an overloaded cable node is the most common non-cap cause of intermittent packet loss. If loss appears reliably in the evening and clears up overnight, call Xfinity at (978) 723-5746 and ask for a technician to check power levels and SNR on your modem at the tap.

Xfinity packet loss quick-fix table

AT&T Packet Loss Test & Fix

AT&T Fiber customers should see very low or zero packet loss under normal conditions — fiber-optic connections are significantly more resilient than cable or DSL. AT&T DSL and older U-Verse copper customers are more susceptible to loss, and the causes differ from fiber.

AT&T Fiber packet loss — common causes

AT&T Fiber uses FTTH (fiber-to-the-home) technology. Packet loss on AT&T Fiber typically points to one of: an issue with the ONT (Optical Network Terminal) installed at your home, a damaged or dirty fiber connector, or a configuration issue with the BGW320 or BGW210 gateway. First check: look at the ONT’s indicator lights. Solid green = normal. Blinking red or amber = signal problem — restart the ONT and call AT&T if the light doesn’t return to green.

AT&T DSL packet loss — common causes

AT&T DSL runs on copper phone lines, which are far more susceptible to packet loss than fiber. Common causes include line noise from aging wiring, electrical interference, distance from the DSLAM (central office), and wet or damaged outdoor cables. If you’re experiencing significant packet loss on AT&T DSL and AT&T Fiber is available at your address, upgrading eliminates virtually all DSL-related loss.

AT&T packet loss diagnosis

Run the test at the top of this page before calling AT&T — knowing your exact packet loss percentage and whether it’s present on wired Ethernet will significantly speed up the support call.