CenturyLink (now called Lumen Technologies) serves millions of internet customers across the United States. If your connection feels sluggish, the first step is running a speed test to see what you're actually getting. This guide walks you through how to test your CenturyLink speeds, what results to expect, and what to do if your numbers are lower than what you're paying for.
How to Test Your CenturyLink Speed
There are a few ways to check your CenturyLink internet speed. Each option gives you slightly different results, and it's smart to use more than one.
Option 1: Use Speedtest.now
The fastest way to check your speed is to run a speed test right here. It takes about 30 seconds and measures your download speed, upload speed, and ping. You don't need to install anything or create an account. Just click the button and wait.
Option 2: CenturyLink's Own Speed Test
CenturyLink offers a speed test tool on their website at internethelp.centurylink.com. It works fine, but keep in mind that ISP-hosted tests sometimes show slightly higher results. That's because the test server is often located close to or inside their own network. An independent test gives you a more realistic picture of your everyday speeds.
Option 3: Use the My CenturyLink App
CenturyLink's mobile app includes a built-in speed test. It's handy for quick checks, but for the most accurate results, always test from a computer connected to your router with an ethernet cable.
Tips for Getting Accurate Results
A speed test is only useful if the results reflect your real connection. Here are a few things to do before you hit the test button.
Use a Wired Connection
Wi-Fi adds extra variables like signal strength, interference, and distance from the router. Plug an ethernet cable directly into your computer for the most honest measurement. If you can't do that, at least sit close to the router and make sure no walls are blocking the signal. For more on this, check out our guide on how to improve Wi-Fi speed.
Close Other Apps and Devices
Streaming Netflix on one device while running a speed test on another will drag your results down. Pause all downloads, close background apps, and ask other people in your house to pause their activity for a minute. You want the full bandwidth going to your test device.
Test at Different Times
Internet speeds often dip during peak hours — usually between 7 PM and 11 PM when everyone in your neighborhood is online. Run tests in the morning, afternoon, and evening to get a complete picture. If your speeds only drop at night, that points to network congestion rather than a problem with your equipment.
CenturyLink Speed Plans and What to Expect
CenturyLink offers both DSL and fiber plans depending on your location. The speeds you should see depend entirely on which plan you have. Here's a breakdown of their common plans and what real-world speeds typically look like.
| Plan | Advertised Download | Typical Real Download | Advertised Upload | Connection Type |
|---|---|---|---|---|
| Simply Unlimited | Up to 100 Mbps | 70–95 Mbps | Up to 10 Mbps | DSL / Bonded DSL |
| Fiber 200 | 200 Mbps | 180–200 Mbps | 200 Mbps | Fiber |
| Fiber 500 | 500 Mbps | 450–500 Mbps | 500 Mbps | Fiber |
| Fiber Gigabit | 940 Mbps | 800–940 Mbps | 940 Mbps | Fiber |
| DSL (Legacy) | Up to 40 Mbps | 10–30 Mbps | Up to 5 Mbps | DSL |
Notice how fiber plans deliver speeds very close to what's advertised, while DSL plans often fall short. That's the nature of DSL — your speed depends on how far you are from CenturyLink's nearest equipment hub. The farther away you are, the slower your connection. If you want to understand these differences better, read our cable vs. fiber internet comparison.
Understanding Your Speed Test Results
Your speed test gives you three main numbers. Here's what each one means and what's considered good.
Download Speed
Download speed measures how fast data comes to your device. It affects streaming, browsing, and downloading files. For most households, 50 Mbps is enough for basic use, while 200 Mbps or more handles 4K streaming and multiple users comfortably. If you're getting less than 80% of your plan's advertised speed on a wired connection, something might be wrong.
Upload Speed
Upload speed measures how fast you can send data from your device. This matters for video calls, uploading files to the cloud, and live streaming. CenturyLink's fiber plans offer symmetrical speeds (same upload and download), which is a big advantage. DSL plans have much lower upload speeds — often 5–10 Mbps. Learn more about what counts as a good upload speed.
Ping and Latency
Ping (also called latency) measures the delay between your device and the test server, shown in milliseconds (ms). Lower is better. On CenturyLink fiber, you should see ping between 5–20 ms. On DSL, expect 20–60 ms. Anything above 100 ms will feel laggy, especially for gaming or video calls. You can run a dedicated ping test to measure this more precisely.
What to Do if Your Speeds Are Lower Than Expected
If your test results are significantly below your plan speed, don't panic. There are several common causes and fixes.
Restart Your Equipment
Unplug your CenturyLink modem and router, wait 30 seconds, then plug them back in. This clears temporary issues and refreshes your connection. It fixes the problem more often than you'd think.
Check Your Hardware
Old modems and routers can bottleneck your connection. If you're on a 200 Mbps plan but your router only supports 100 Mbps speeds, your hardware is the limit. CenturyLink's C4000 and C4000LG modems support gigabit speeds. If you're using an older model like the C1100T, ask CenturyLink for an upgrade.
Look for Network Issues
Check CenturyLink's outage page or call their support line at 1-800-244-1111. Sometimes slow speeds are caused by outages or maintenance in your area. If speeds are consistently bad, CenturyLink may need to send a technician to check the line running to your house.
Consider Your Plan
If you're on a DSL plan and consistently getting 15–20 Mbps, that might actually be normal for your distance from the nearest hub. In that case, the fix isn't troubleshooting — it's upgrading to fiber if it's available in your area. You can check availability on CenturyLink's website by entering your address.
For a deeper look at slow connection causes, read our article on why your internet might be slow.
Quick Summary
Testing your CenturyLink speed takes under a minute and can save you hours of frustration. Use a wired connection, close other apps, and test at different times of day for the best picture. Fiber customers should see speeds within 90–100% of their plan. DSL customers will see more variation, especially at longer distances from CenturyLink's equipment. If your results are consistently low, restart your gear, check for outages, and contact CenturyLink support with your test results as proof. Having real numbers in hand makes the conversation much easier.