Measuring correctly
What is an internet speed test? What it measures and how
An internet speed test sends and receives data between your device and a server for a short time to measure what your connection can really do. It reports download and upload speed (Mbps), ping and jitter (ms), and how responsive the line stays when busy (RPM). A typical fixed-line result on HIZTESTI is 43.5 Mbps down, 14.1 Mbps up and 21 ms ping.
- 43.5 Mbps
- Typical download (fixed line)
- 14.1 Mbps
- Typical upload (fixed line)
- 21 ms
- Typical ping (fixed line)
- 499
- Typical responsiveness (RPM, fixed line)
The typical value is the one half of measurements sit above and half below; a few extreme results can't skew it. It's a useful reference, but the comparison that matters is with your own plan. These measurements come from Turkey.
What does a speed test measure?
- Download speed: how fast data reaches your device. Streaming, downloads and opening pages rely on it. It's measured in Mbps; we explain the unit in what is Mbps.
- Upload speed: how fast data leaves your device. It decides video calls and cloud backups; we show why in why upload speed matters.
- Ping: the round trip from your device to the server. In games and calls you feel it more than speed. More in what is ping.
- Jitter: how much ping wobbles during the test. A common cause of choppy video and audio; see what is jitter.
- Responsiveness (RPM): how many request-response round trips the connection completes per minute while the line is busy. If it's low, calls freeze even when speed looks high.
How does HIZTESTI measure?
The test runs against measurement servers whose software we build and operate; the machines sit in sponsor data centres. Download and upload each run for 15 seconds over several parallel connections; a single connection can't fill most fast lines.
The speed samples from those 15 seconds are first reduced to 20 slices. The slowest 30% and the fastest 10% are then dropped and the rest are averaged. That way the warm-up at the start doesn't drag the result down and short "speed bursts" some providers allow don't inflate it; what you see is the speed the line can sustain.
Ping is measured over a separate connection from the download and upload traffic. So you see idle response time and response time under load separately; the gap between them exposes a problem called bufferbloat.
The full method is open, with a technical report under a permanent identifier: Our measurement method
How much do results vary?
In fixed-line measurements the slowest tenth are below 6.6 Mbps, while the fastest tenth are above 198.0 Mbps. The gap comes from plans, infrastructure, Wi-Fi and conditions at the moment of testing. That's why one result never tells the whole story of your line.
Getting a reliable result
- If you can, connect your computer to the router with a cable; Wi-Fi noticeably lowers the result.
- Make sure nothing else at home is downloading, streaming or backing up during the test.
- Keep only the speed test tab open; we cover background tabs in how to run a speed test correctly.
- Turn off battery saver on your phone or laptop.
- Run several tests, and repeat at different times of day.
Run a test first to see where your result sits. Start a speed test
What each number in your result means: How to read speed test results
The data in detail: charts and diagrams
Spread of download and upload speeds
| Slowest 10% | Typical | Fastest 10% | |
|---|---|---|---|
| Fixed · download | 6.6 Mbps | 43.5 Mbps | 198.0 Mbps |
| Fixed · upload | — | 14.1 Mbps | 52.1 Mbps |
| Mobile · download | 3.0 Mbps | 23.7 Mbps | 117.3 Mbps |
| Mobile · upload | — | 11.9 Mbps | 36.9 Mbps |
HIZTESTI measurements · 1 Jul – 28 Sep 2026 · fixed and mobile
Frequently asked questions
- Does a speed test slow down my internet?
- Only while it runs. The test fills your line briefly and everything returns to normal when it ends. Other devices on the same line may slow down a little during the test.
- Why do I get a different result every time?
- Internet traffic changes constantly: other devices at home, Wi-Fi conditions and your provider's load at that moment all affect the result. The middle of several tests is more reliable than any single one.
- How much data does a speed test use?
- It scales with your speed: the faster the line, the more data moves in each 15-second phase; on a gigabit line the total can reach a few gigabytes. If you're testing on mobile data, keep your allowance in mind.
- Which server should I test against?
- One close to you. A distant server can show higher ping and lower speed even when your line is fine. HIZTESTI picks the server with the lowest ping by default.
Sources
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