- Key Takeaway: Your speed test shows five main numbers — download speed, upload speed, ping, jitter, and sometimes bufferbloat — and each one affects a different part of your internet experience.
- Key Takeaway: Testing over Wi-Fi almost always gives lower results than testing with a wired Ethernet connection, so always test wired first to rule out Wi-Fi as the problem.
- Key Takeaway: Slow speed test results are usually caused by Wi-Fi interference, outdated hardware, network congestion, or too many connected devices — all of which are fixable.
You have probably been told to "run a speed test" when your internet feels slow. But once you see the results, the numbers can be confusing. What counts as a good download speed? Why is your upload speed so much lower? What on earth is jitter?
This guide explains exactly what every number on your speed test means, how to run the test correctly so your results are accurate, and what to do step by step when your speeds are not matching what you pay for.
What Each Speed Test Metric Means
Download Speed
Download speed measures how fast data travels from the internet to your device. It is measured in Mbps (megabits per second). This is the number that matters most for everyday activities like streaming video, loading web pages, scrolling social media, and downloading files.
A general guide for download speed in 2026:
- 25 Mbps: Enough for one person browsing and streaming in HD
- 100 Mbps: Good for a household of 2-3 people with moderate use
- 300 Mbps: Handles multiple 4K streams, video calls, and gaming at the same time
- 500 Mbps or higher: Ideal for large households, heavy downloading, and smart home setups
Upload Speed
Upload speed measures how fast data travels from your device to the internet. This matters for video calls, live streaming, uploading files to cloud storage, posting videos to social media, and online gaming. Upload speeds are almost always lower than download speeds on cable and DSL connections. Fiber connections often offer symmetrical speeds, meaning upload and download are the same.
If your upload speed is below 5 Mbps, you will likely notice lag on video calls and slow file uploads.
Ping (Latency)
Ping measures the time it takes for a small packet of data to travel from your device to the test server and back. It is measured in milliseconds (ms). Lower is better.
- Under 20 ms: Excellent — ideal for competitive gaming and real-time applications
- 20-50 ms: Good — fine for most activities including casual gaming and video calls
- 50-100 ms: Acceptable — you may notice slight delay on video calls
- Over 100 ms: Poor — noticeable lag in games, video calls may stutter
Jitter
Jitter measures the variation in your ping over time. If your ping bounces between 15 ms and 80 ms during a test, your jitter is high. High jitter causes choppy video calls, distorted audio, and inconsistent gaming performance even when your average ping looks fine. You want jitter under 10 ms for a stable connection.
Bufferbloat
Bufferbloat is a lesser-known metric that not all speed tests measure, but it is one of the most important for real-world performance. It shows how much your latency increases when your connection is under heavy load — for example, when someone in your household starts a large download while you are on a video call.
A connection with bad bufferbloat might have 20 ms ping when idle but spike to 300 ms or more under load. Tools like Waveform's bufferbloat test at waveform.com/tools/bufferbloat specifically test for this. A grade of A or B is good. A grade of C or lower means bufferbloat is likely causing problems during peak usage.
How to Run a Speed Test Correctly
An inaccurate speed test leads to wrong conclusions. Follow these steps to get results you can actually trust.
Step 1: Test With a Wired Connection First
Connect your computer directly to your modem or router using an Ethernet cable. This removes Wi-Fi from the equation and shows you the true speed your equipment is delivering. If your wired speeds match your plan but your Wi-Fi speeds do not, you know the problem is your wireless setup — not your ISP or modem.
Step 2: Close Background Applications
Before running the test, close any apps that use the internet. This includes streaming services, cloud backup programs, file downloads, software updates, and other browser tabs. On your phone, close background apps. If other people in your home are using the internet, ask them to pause their activity briefly or be aware that their usage will affect your results.
Step 3: Use a Reliable Speed Test Tool
These are the most trusted speed test tools available:
- Speedtest by Ookla (speedtest.net) — The most widely used option; tests download, upload, and ping
- Fast.com (fast.com) — Run by Netflix; simple interface with latency details if you click "Show more info"
- Waveform Bufferbloat Test (waveform.com/tools/bufferbloat) — Best for testing bufferbloat specifically
- Google Speed Test — Just search "speed test" in Google and click "Run Speed Test" directly in the search results
Step 4: Run Multiple Tests
Run the test at least three times and at different times of day. Internet speeds naturally fluctuate based on network congestion in your area. Testing once in the morning and once in the evening gives you a more complete picture. If your speeds are consistently 20% or more below your plan, that is worth investigating.
Step 5: Compare Wired vs. Wireless
After testing wired, disconnect the Ethernet cable and run the same test over Wi-Fi from the location where you normally use the internet. Comparing these two results tells you exactly how much speed you are losing to your wireless setup.
What to Do When Your Speed Test Results Are Slow
If your speeds are not matching your internet plan, work through these steps in order. Start with the easiest fixes first.
Fix 1: Restart Your Modem and Router
Unplug your modem and router from power. Wait 30 seconds. Plug the modem back in first and wait for all the lights to stabilize (about two minutes). Then plug in your router. This clears temporary memory issues and often resolves speed drops immediately.
Fix 2: Check for Network Congestion
If speeds are slow only during certain hours — typically evenings between 7 and 11 PM — network congestion in your area is the likely cause. Cable internet is especially susceptible to this because you share bandwidth with your neighbors. There is no quick fix for area congestion, but upgrading to a DOCSIS 3.1 modem or switching to a fiber plan (if available) can help. You can browse DOCSIS 3.1 modems on ModemGuides.com if your current modem only supports DOCSIS 3.0.
Fix 3: Reduce Wi-Fi Interference
If your wired speed test is fine but Wi-Fi is slow, interference is the most common cause. Try these steps:
- Move your router to a central, elevated location away from walls, microwaves, and baby monitors
- Switch from the 2.4 GHz band to the 5 GHz or 6 GHz band on your router for faster short-range speeds
- Change your Wi-Fi channel in your router settings to avoid overlap with neighbors — channels 1, 6, or 11 are best for 2.4 GHz
Fix 4: Check How Many Devices Are Connected
Every device connected to your network uses a share of your bandwidth, even when idle. Smart home devices, security cameras, tablets, and gaming consoles all add up. Log into your router's admin page (usually at 192.168.0.1 or 192.168.1.1) and check the connected devices list. Remove or disconnect anything you do not recognize or no longer use.
Fix 5: Update Your Modem and Router Firmware
Outdated firmware can cause slow speeds, dropped connections, and security vulnerabilities. Check your modem and router manufacturer's website for the latest firmware version. Many newer routers update automatically, but older models require a manual update through the admin page.
Fix 6: Check Your Cables
Damaged or old coaxial cables and Ethernet cables can silently limit your speeds. If your coaxial cable is more than 10 years old, has tight bends, or is connected through multiple splitters, it may be degrading your signal. Remove any unnecessary coaxial splitters between the wall outlet and your modem. For Ethernet, make sure you are using at least a Cat5e cable — older Cat5 cables cannot handle gigabit speeds.
Fix 7: Upgrade Your Hardware
If you have worked through every fix above and your wired speeds are still well below your plan, your modem or router may be the bottleneck. An older DOCSIS 3.0 modem cannot deliver the speeds of a 500 Mbps or gigabit cable plan. A Wi-Fi 5 router will not keep up with modern demands the way a Wi-Fi 6 or Wi-Fi 7 router can.
Check out our buying guides to find the right modem and router for your ISP and speed tier.
Fix 8: Contact Your ISP
If your wired speeds are consistently far below your plan after trying all of the above, the problem may be on your ISP's end. Call your provider and reference your speed test results, specifically the wired test results, the times you tested, and how far below your plan the numbers were. Ask them to check your line signal levels and look for issues at the node level. Having this data ready makes it much harder for them to deflect.
Understanding Your Results: Quick Reference
Download speed below plan by 20% or more (wired): Possible modem issue, ISP congestion, or line problem. Try restarting equipment first, then contact your ISP.
Upload speed very low: Normal on cable and DSL plans. If it is significantly below what your plan advertises, restart your modem and check for firmware updates.
High ping (over 100 ms): Could be a congested network, a server far from your location, or a Wi-Fi issue. Switch to wired and retest. If still high, contact your ISP.
High jitter (over 10 ms): Often caused by Wi-Fi interference or network congestion. Test on a wired connection to isolate the cause.
Bad bufferbloat (grade C, D, or F): Your router may lack proper queue management (called SQM or QoS). Some routers have a QoS or Smart Queue Management setting you can enable. If yours does not, a router upgrade may be needed.
Frequently Asked Questions
What is a good internet speed test result?
A good result depends on your plan and household size. In general, 100 Mbps download is enough for most households of 2-3 people. 300 Mbps or more is ideal for larger households with multiple devices streaming and gaming at the same time. Your results should be within about 80% of the speed your ISP plan advertises when tested over a wired connection.
Why is my internet speed test result so much lower than my plan?
The most common reasons are testing over Wi-Fi instead of wired Ethernet, network congestion during peak evening hours, too many devices using your connection at once, outdated modem or router hardware, or signal issues on your line. Test with an Ethernet cable first to rule out Wi-Fi as the cause.
What is the difference between download speed and upload speed?
Download speed measures how fast you can pull data from the internet to your device, which affects streaming, browsing, and downloading files. Upload speed measures how fast you can send data from your device to the internet, which affects video calls, live streaming, uploading files, and cloud backups. Most cable and DSL plans have much faster download speeds than upload speeds.
What does ping mean on a speed test?
Ping, also called latency, measures how quickly your device can communicate with a server. It is shown in milliseconds (ms). Lower ping means more responsive internet. Ping under 50 ms is good for most uses. Under 20 ms is ideal for competitive online gaming. High ping causes noticeable lag in games and delay on video calls.
What is bufferbloat and how do I fix it?
Bufferbloat happens when your router's buffer fills up with too much data during heavy use, causing latency to spike dramatically. It makes video calls stutter and games lag even though your raw speeds might look fine. You can test for it at waveform.com/tools/bufferbloat. To fix it, enable SQM or QoS in your router settings if available, or upgrade to a router that supports Smart Queue Management.
Should I test my internet speed on Wi-Fi or Ethernet?
Always test on a wired Ethernet connection first. Wi-Fi adds variables like signal strength, interference, distance from the router, and the Wi-Fi standard your device supports. A wired test gives you the true speed your modem and ISP are delivering. Then test on Wi-Fi to see how much speed you are losing to your wireless setup.
How often should I run a speed test?
Run a speed test whenever your internet feels slow and at least once a month to track your connection's performance over time. Test at different times of day to spot congestion patterns. If you are consistently getting speeds far below your plan, document your results before calling your ISP so you have data to reference.
