How to test your router's data transfer speed?

Question

I've an internet connection of 50Mbps, but on speed test on my laptop over WIFI, it shows variable speed, sometimes 20Mbps or sometimes even less than 1Mbps. So I connected WAN cable directly to my laptop, so then it showing the speed of 50Mbps exactly. So I'm pretty sure it is my router's issue. But I want to check what's my router's max speed not the internet. How can I test this?

Sure it can be, if the channel isn't overused (my laptop can reach 120 Mbps via .11n – that's faster than its built-in Ethernet...) Depends a lot on environment of course. Spectrum analyzer or even a basic "WiFi analyzer" app might give some clues. — u1686_grawity, Sep 23 '17 at 12:35
Maybe @DavidPostill should of said Wifi is never as reliable as ethernet.... — djsmiley2kStaysInside, Sep 23 '17 at 13:55
How close is your computer to the router and are there obstacles like walls? Try to set the router to channel 11 or another for testing. Are there other wifi networks around where you live? What is the latency on wifi ([this test](https://www.speedcheck.org/) will tell you)? — harrymc, Apr 18 '19 at 12:55
Not OP, but I too am looking for a way to find out the speed of my router. Please note that I'm not trying to debug why it's slow or anything, I just need to make that measurement - regardless of what other issues may be standing in the way of achieving maximum speed. An answer to the question in title - how to **test** the ***router's*** speed (and only router, not the internet) would be extremely helpful. — laggingreflex, Apr 19 '19 at 04:31

score 2 · Answer 1 · answered Apr 19 '19 at 11:36

If you have two available computers, you can measure the TCP speed directly between them, without using file-transfer which is notoriously slow.

The tool to use is iPerf, available for all major operating systems.

For details see the article How to use Iperf to test the speed on TP-Link routers.

The schema of test configuration is:

Use your computer as the server connected via Wifi. Both computers should be on the LAN side of the router. You may connect the computer you are not testing to the router by cable (if faster), to ensure that its performance is not the bottleneck in the test.

The main points are:

Install iPerf on both computers
Disable all firewalls
Set static IP address for PC A
Set static IP address for WAN port of the Router (your router configuration must support this)
On PC A start the server:
```
Iperf3 -s
```

on PC B run the command :

Iperf3  -c  192.168.2.30   (replace IP as required)

The result may look like this (on the sender) when the speed is 95 Mbps:

score 0 · Answer 2 · edited Apr 18 '19 at 00:35

Wi-Fi isn't the best or qualified method to check the router speed, since your connection by Ethernet works gives you the correct speed then the router is fine I guess.

Wi-Fi is great because you don't need cables but still on the other hand the performance varies from many factors:

Distance (the bigger the distance the lower signal you get so speed too)
channel (an overused channel may drop the speed... with the help of a Wi-Fi Analyzer application you can check and make a decision on changing your channel for better results)
obstacles/environment (walls, irons, mirrors or whatever may drop the signal rates and the speed too)
another factor is the Wi-Fi dongle. For example, I have three here, and each of them gives a different performance.

How to test your router's data transfer speed?

2 Answers2