You run a speed test at 2 PM on a Tuesday. Result: 320 Mbps download. You run the same test at 8 PM on a Friday. Result: 87 Mbps. You call your ISP to complain, and they say: "We guarantee up to 1000 Mbps. Your speed is within the acceptable range." You feel like you are being scammed. You probably are.

This guide explains why your speed test results do not match what you pay for, how to run a proper speed test, and how to prove to your ISP that they are not delivering the speed you pay for.

Why Speed Tests Show Lower Speeds Than Your ISP Advertises

There are 6 reasons your speed test might show lower speeds:

  1. You are testing over WiFi (not Ethernet): WiFi is slower than wired. Always test with Ethernet (connect laptop directly to router with cable).
  2. Peak-hour congestion: Cable internet is shared bandwidth. At 7-10 PM, your speed drops because your neighbors are also using internet.
  3. Your device is old: If your laptop/phone is from 2018 or earlier, it might not support the WiFi standards needed for high speeds.
  4. Your router is old: A 2019 router cannot deliver 2026 speeds, even if your ISP sends 1000 Mbps to your home.
  5. The speed test server is far away: Speedtest.net connects you to the closest server. If the closest server is 200 miles away, your speed will be lower.
  6. Your ISP is "throttling": Some ISPs slow down certain types of traffic (Netflix, YouTube) during peak hours. This is called "traffic shaping" or "throttling."
Key insight: ISPs advertise "up to" speeds, not "guaranteed" speeds. "Up to 1000 Mbps" means you might get 1000 Mbps, or you might get 100 Mbps. It is legal (and scummy).

How to Run a Proper Speed Test

  1. Use Ethernet (wired): Connect your laptop directly to the router with an Ethernet cable. Do not use WiFi for speed tests.
  2. Close other apps: If you are downloading a game on Steam, your speed test will show lower speeds. Close everything.
  3. Test at different times: Run tests at 2 PM (off-peak), 7 PM (peak), and 11 PM (late night). This shows the ISP whether you have a congestion problem.
  4. Use multiple speed test sites: Try speedtest.net, fast.com (Netflix's speed test), and google.com/search?q=speed+test. If all three show similar results, the test is accurate.
  5. Test to different servers: On speedtest.net, click "Change Server" and pick a server close to you (within 100 miles).

What Speeds Should You Actually Get? (Reality Check)

Plan You Pay ForWhat You Should Get (Wired, Off-Peak)What You Might Get (WiFi, Peak)
100 Mbps90-100 Mbps40-70 Mbps
300 Mbps270-300 Mbps100-200 Mbps
500 Mbps450-500 Mbps150-300 Mbps
1000 Mbps900-1000 Mbps200-500 Mbps

The pattern: Over WiFi during peak hours, you typically get 40-60 percent of your wired off-peak speed. This is normal (not a scam). But if you get less than 30 percent consistently, call your ISP.

How to Prove Your ISP Is Not Delivering Promised Speed

If you want to complain to your ISP (or threaten to cancel), you need evidence. Here is how to collect it:

  1. Run speed tests for 7 days: Once per day, at the same time, with Ethernet. Record the results in a spreadsheet.
  2. Note the time and server used: "Monday 2 PM, Speedtest.net, server: Comcast Chicago, result: 320 Mbps."
  3. Compare to your plan: If you pay for 500 Mbps and consistently get <200 Mbps (wired, off-peak), you have a case.
  4. Call your ISP with the data: Say: "I ran speed tests for 7 days. I pay for 500 Mbps. My average speed is 180 Mbps. Can you fix this or lower my bill to match the speed I actually get?"

Why "Up to" Speeds Are Legal (and How to Fight Back)

The FCC allows ISPs to advertise "up to" speeds because "network conditions" affect speed. But some states (California, New York) have "broadband truth" laws that require ISPs to provide "typical speeds" (not just "up to" speeds). If you live in one of these states, you can file a complaint with the state attorney general if your speed is consistently below 80 percent of advertised.

⚠️ Before you complain: Make sure you are testing correctly. 90 percent of "my ISP is lying about speed" complaints are actually "I tested over WiFi and expected wired speeds." Test with Ethernet first.

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Frequently Asked Questions

Is fast.com (Netflix) or speedtest.net more accurate?

They are both accurate, but they test different things. Speedtest.net tests your speed to the closest server (best case). Fast.com tests your speed to Netflix servers (real-world streaming speed). If speedtest.net shows 500 Mbps but fast.com shows 50 Mbps, your ISP might be throttling Netflix.

Why is my upload speed so much lower than download?

Cable and DSL internet are "asymmetric"—they give you much more download speed than upload. This is because most users download more than they upload. Fiber is "symmetric" (same upload and download). If upload speed matters to you, switch to fiber.

Last updated: July 2026. Speed test methodology from FCC Broadband Speed Guide.