What Speedtest measures

The standard online Speedtest used to measure ping, jitter, download speed and upload speed.

Speedtest Custom speed tests still perform these measurements.

Nowadays Speedtest measures:

  1. Idle latency
  2. Download latency
  3. Upload latency
  4. Download speed
  5. Upload speed

Latency

There are multiple definitions of latency. We prefer the definition of SpeedGuide: Latency, or simply delay is an expression of how much time it takes for a packet of data to get from one designated point to another. Latency is often measured by sending a packet that is returned to the sender and the round-trip time (RTT) is considered the latency.

Latency is often measured in milliseconds (ms).

Latency versus ping

Speedtest uses the word "Ping" to describe latency. However, "Ping" is a standard tool that measures latency (also known as ping time). So Speedtest measures latency, but calls it "Ping".

Idle latency

The latency measured when the system is idle (there is no internet traffic).

In an earlier test we came to the conclusion that Speedtest measures (idle) latency relatively accurately.

Download latency

The latency measured at the moment a (large) download takes place.

Note that large downloads have also a negative impact on the measured download speed.

Upload latency

The latency measured at the moment a (large) upload takes place.

Download speed

The amount of data your system can receive and process per second. When you measure download speed, you are measuring the capacity of the weakest link (from a test server to your device).

Download speed is often measured in mega bits per second (Mbps).

Upload speed

The amount of data your system can send per second. When you measure upload speed, you are measuring the capacity of the weakest link (from your device to a test server).

Upload speed is often measured in mega bits per second (Mbps).

Jitter

Jitter is the variation in latency (hence the unit for jitter is also milliseconds (ms)). The lower the jitter, the smoother the data arrives.

Quality indicators

Based on these measurements, Speedtest might indicate your:

  1. Browsing Quality An icon of an opened internet browser with 5 green dots below
  2. Gaming Quality An icon of a game console browser with 5 green dots below
  3. Streaming Quality An icon of avideo player with 4 light green dots below
  4. Video Call Quality An icon of a video call with 5 green dots below

This always involves an assessment on a scale of zero to five.

We suspect this is an experimental feature. These quality indicators are not always shown (spring 2025).