How to Properly Check Internet Speed ​​via a Wi-Fi Router: From Theory to Practice

Are you paying your provider for 300 Mbps internet, but 4K videos are constantly freezing and files are downloading at a snail's pace? The problem may lie not with your plan, but with the connection itself. Wi-Fi router — its settings, overload, or hardware limitations. Checking the actual internet speed through a router is more difficult than it seems: the results are influenced by dozens of factors, from the distance to the device to interference from neighboring networks.

In this article we will analyze 5 reliable methods Diagnostics—from basic tests to professional tools. You'll learn how to distinguish router problems from ISP-side issues, why cable and Wi-Fi speeds differ significantly, and what to do if your router is throttling your traffic. And also— How to identify hidden limitations even on top models like ASUS RT-AX88U or TP-Link Archer AX6000, which they "forget" to mention in advertising.

Why is my router's speed always lower than my ISP's?

Even a new router for 15 000 ₽ It doesn't guarantee you'll get the same speed as your ISP's cable service. Here are the key reasons:

• 📡 Air transmission lossesWi-Fi operates in a noisy band (2.4 or 5 GHz), where the signal is weakened by walls, furniture, and neighboring networks. Under ideal conditions, signal loss is 30-50%; in reality, it can be up to 70%.
• 🔌 LAN/WAN port limitations: Budget routers (for example, D-Link DIR-615) are often equipped with ports 100 Mbps, which physically won’t let through more, even if the provider provides 500 Mbps.
• ⚙️ QoS settings and bandwidth limits: Enabled function QoS (Quality of Service) can artificially throttle traffic for individual devices if the router does not prioritize correctly.
• 🔄 CPU overload: Simultaneous operation of 10+ devices, torrents, or IP cameras load the router's CPU, causing speed to drop even with a free channel.

Before you accuse your provider of cheating, check maximum theoretical speed your router. For example, the standard Wi-Fi 5 (802.11ac) in single-threaded mode it gives up to 433 Mbps at 5 GHz, and Wi-Fi 6 (802.11ax) — to 1200 MbpsBut this is under laboratory conditions! On a home network, the actual speed rarely exceeds 60-70% of the advertised speed.

⚠️ AttentionIf your router is older than 2018, it most likely does not support modern standards. Wi-Fi 6/6EThis means that even with a 1 Gbps tariff, you physically won't be able to get more. 866 Mbps via wireless network.

Method 1: Testing Cable Speed ​​(Basic Method)

The first step is to eliminate the Wi-Fi interference. To do this, connect your computer or laptop to the router. via network cable (preferably Cat 5e or higher) and take a speed test. This way you will find out How much does the provider actually give? and whether the router itself is cutting off the traffic.

Use the services:

• 🌍 Speedtest.net (popular, but sometimes inflates results due to nearby servers).
• 📊 Fast.com (from Netflix, shows actual streaming speed).
• 🛡️ Yandex.Internetometer (good for checking ping and stability).

How to test correctly:

1. Disconnect all devices from the router except the test PC.
2. Close background programs (torrents, cloud synchronization, Windows updates).
3. Perform 3-5 tests in a row and take the average.
4. Compare the result with your provider's tariff. If the difference is more than 20%, the problem is with your provider or router.

Disable Wi-Fi on the test device|

Use a cable no longer than 5 meters|

Reboot the router 2 minutes before the test|

Check that the cable is connected to the WAN (Internet) port of the router, and not the LAN port.

If the cable speed matches the plan's speed limit, but the Wi-Fi speed is significantly lower, the problem is with the wireless network. If the cable speed is also low, the problem is with the ISP or a faulty router (for example, a burned-out WAN port).

Up to 100 Mbps|

100–300 Mbps|

300–500 Mbps|

500 Mbps and above-->

Method 2: Check Wi-Fi speed on different devices

Wi-Fi speed depends not only on the router, but also on client deviceFor example, a smartphone iPhone 12 supports Wi-Fi 6, but only in the 5 GHz range, and an old laptop with an adapter 802.11n will not exceed 150 Mbps even on a top-end router.

To objectively evaluate Wi-Fi speed:

1. Connect 2-3 devices with different adapters to the router (for example, MacBook Pro (Wi-Fi 6), Samsung Galaxy S22 (Wi-Fi 6E) and an old tablet on Wi-Fi 4).
2. Run a speed test on each device while standing close to the router (1–2 meters).
3. Repeat the test in another room (5-10 meters from the router).

If the speed is lower near the router on modern devices 300 Mbps (for Wi-Fi 5) or 600 Mbps (for Wi-Fi 6) — the problem lies in the router settings or hardware limitations. If the speed drops significantly in the next room, interference or a weak signal is to blame.

Method 3: Analyze the router's CPU and memory load

Few people know, but a router is a mini-computer with a processor, RAM, and firmware. If the CPU is loaded to 100%, internet speed will drop even with a free channel. You can check the load using router web interface:

Instructions for popular models:

• 🔧 ASUS: Go to Administration → System Monitor.
• 🌐 TP-Link: Open Additional settings → System tools → Statistics.
• 📶 Keenetic: Go to System → Monitoring → System Load.
• 🔄 MikroTik: Use System → Resources.

Normal values:

• 🟢 CPU: up to 30% at idle, up to 70% under load.
• 🟢 RAM: at least 20% of the total volume is free.
• 🔴 Critical: CPU load is 90%+ for more than 5 minutes - the router cannot handle the load.

If the processor is overloaded:

• 🔄 Reboot your router (sometimes it helps).
• 🚫 Disable unnecessary features: QoS, Parental Control, IPv6 (if you don't use it).
• 🔄 Update your firmware (outdated versions often contain bugs that overload the CPU).
• 🛒 If your router is older than 5 years, consider replacing it. Budget models (for example, Tenda AC10) are physically unable to handle modern loads.

⚠️ Attention: On routers with processors Single-Core (Single-core) processors, even simple torrent distribution can consume 100% of the CPU. Check your model's specifications on the manufacturer's website.

Method 4: Checking the speed via the command line (for advanced users)

If your router's web interface doesn't show your actual speed, and services like Speedtest.net seem inaccurate, use console utilitiesThey provide more objective data, as they exclude the influence of the browser and its cache.

For Windows:

1. Open the command prompt (Win + R → enter cmd).
2. Enter the command to check the download speed:
   bitsadmin /transfer myDownloadJob /download /priority normal "http://speedtest.tele2.net/10GB.zip" "%CD%\10GB.zip"
3. To stop the test, press Ctrl + C.

For macOS/Linux:

1. Open Terminal.
2. Install iperf3 (if not installed):
   brew install iperf3 (macOS) or sudo apt install iperf3 (Linux).
3. Connect to the test server:
   iperf3 -c speedtest.serverius.net -P 10

Results iperf3 they will show real throughput without the influence of HTTP/HTTPS protocols. This is useful for diagnosing problems with MTU, TCP-windows or packet losses.

ping -f -l 1472 ya.ru

Method 5: Diagnosing Wi-Fi interference and channel selection

If the Wi-Fi speed is unstable (sometimes it’s high, sometimes it drops to zero), it’s your fault interference from neighboring networks or household appliances. To identify them:

Step 1: Scan the airwaves using specialized utilities:

• 📱 For Android: WiFi Analyzer (shows channel load).
• 🍎 For iOS: AirPort Utility (hidden scanning function).
• 💻 For Windows: inSSIDer or NetSpot.

Step 2: Determine the clearest channel:

• For 2.4 GHz choose channels 1, 6 or 11 (they do not intersect).
• For 5 GHz use channels 36–48 or 149–165 (DFC-range, if supported).

Step 3: Change the channel in your router settings:

• 🔧 ASUS/TP-Link: Wireless Network → 2.4GHz/5GHz Settings → Channel.
• 🌐 Keenetic: Wi-Fi → Access Point → Channel.

Step 4: Check your speed after changing the channel. If there's no improvement, the problem isn't interference, but rather the router itself or its location.

What to do if your router is throttling your speed

If all tests show that your router is artificially limiting your speed, try these steps:

1. 🔄 Reset to factory settings (Reset button for 10 seconds). Often, problems are caused by "correct" settings from previous owners.
2. 📥 Update the firmwareOutdated versions may contain bugs that limit speed. Download firmware only from official website manufacturer.
3. 🔌 Disable resource-consuming features:
   • QoS (if traffic prioritization is not required).
   • IPv6 (if the provider does not support it).
   • Guest network (if not used).