Step 1: Test Wired First
The single most important speed testing tip is this: always start with a wired ethernet connection. Plug a Cat5e or Cat6 ethernet cable directly from your modem or router into your computer. This eliminates Wi-Fi overhead and gives you your true ISP speed. If your wired speed matches your plan, any slowness you experience on devices is a Wi-Fi problem, not an ISP problem. An estimated 70% of speed complaints stem from Wi-Fi issues rather than ISP underperformance.
Step 2: Close Everything Else
Background applications consume bandwidth without you realizing it. Cloud sync services (Dropbox, iCloud, Google Drive), automatic software updates, streaming on other devices, and even browser tabs running ads all compete for your connection. Close everything you can before testing. On a shared household connection, ask others to pause streaming and downloads during the test.
Step 3: Test at Different Times
A single speed test is a snapshot, not the full picture. Cable internet is a shared medium — you share bandwidth with your neighbors. During peak hours (7-11 PM), when everyone is streaming, speeds can drop 20-40%. Run tests at these times for a complete picture:
- Morning (8-10 AM): Low congestion, near-peak performance
- Afternoon (2-4 PM): Moderate usage
- Evening (8-10 PM): Peak congestion — your worst-case speed
- Late night (midnight-2 AM): Minimal congestion — your best-case speed
If your late-night speed is 500 Mbps but your evening speed is 150 Mbps, your ISP's local node is congested. Fiber connections are less affected by peak/off-peak variation because each home has dedicated capacity.
Step 4: Use Multiple Test Services
Different speed tests connect to different servers and use different methodologies. Speedtest by Ookla often connects to ISP-hosted servers, which can show optimistically high results because they bypass potential internet peering congestion. Netflix's Fast.com tests from Netflix CDN servers, showing how fast Netflix content would actually load. Our test measures download throughput from our CDN. Use at least two services and average the results.
Step 5: Understand the Numbers
Your speed test result should be within 80% of your plan speed on a wired connection. Here is what to expect:
| Plan Speed | Expected Wired | Expected Wi-Fi 6 | Expected Wi-Fi 5 |
|---|---|---|---|
| 100 Mbps | 80-100 | 70-95 | 60-80 |
| 300 Mbps | 250-300 | 200-280 | 150-250 |
| 500 Mbps | 420-500 | 300-450 | 200-400 |
| 1 Gbps | 850-940 | 500-800 | 300-500 |
When to Call Your ISP
Contact your ISP if you consistently see less than 70% of your plan speed on a wired connection, particularly during non-peak hours. Document your test results with timestamps. Many ISPs have internal speed test tools that can diagnose whether the issue is on their network or in your home wiring. If your modem is more than 3-4 years old, it may not support the latest DOCSIS standard and could be the bottleneck.
Frequently Asked Questions
What is the most accurate internet speed test?
No single speed test is definitive. For the most complete picture, use at least two: one CDN-based test (like DownloadSpeed or Fast.com) and one server-based test (like Speedtest by Ookla). Always test wired first. If your ISP hosts an Ookla server, those results may be optimistically high because they bypass potential peering congestion.
Why does my speed test show different results each time?
Speed test results vary due to network congestion (other users on your local network and your ISP), Wi-Fi interference, test server load, and background processes on your device. Variations of 10-20% between tests are normal. If results vary by more than 50%, you may have a congestion or equipment problem.
Should I test speed on Wi-Fi or ethernet?
Test both, but ethernet first. Ethernet shows your true ISP speed by eliminating Wi-Fi overhead. If wired speed matches your plan but Wi-Fi is much slower, the bottleneck is your router. If wired speed is also slow, the problem is your ISP or modem. About 70% of "slow internet" complaints are actually Wi-Fi issues.
How fast should my internet be?
The FCC defines broadband as 100 Mbps download and 20 Mbps upload. For most households, 200-500 Mbps handles multiple 4K streams, video calls, and gaming simultaneously. You should consistently get at least 80% of your plan speed on a wired connection. If you consistently get less, contact your ISP.
Does the time of day affect speed test results?
Yes. Cable internet speeds typically drop 20-40% during peak hours (7-11 PM) when many people in your neighborhood stream video. Fiber connections are less affected. Test at several times throughout the day to understand your actual performance range.
Can a VPN affect my speed test?
Yes. A VPN adds encryption overhead and routes traffic through a remote server, typically reducing speeds by 10-30% and adding 10-30 ms of latency. Always disable your VPN before running a speed test to measure your actual ISP speed.