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Internet testing

Why do voices break up on my calls?

Jitter Test

Calls break up and voices sound robotic, even when your speed test looks good.

Is this happening to you?

  • Someone's voice cuts in and out on a call.
  • Video freezes for a second, then jumps forward.
  • A game feels smooth, then briefly stutters for no reason.

Jitter is how much your response time changes from one moment to the next.

Start here

Does this sound familiar?

Three ordinary evenings that end up on this page.

  • Netflix plays perfectly all evening.

    But your Zoom call freezes every few minutes.

    Let us find out why the two behave differently.

  • You are explaining something on a work call.

    People ask you to repeat yourself again.

    This test shows whether your timing is unsteady.

  • A game runs smoothly for ten minutes.

    Then it stutters once, for no obvious reason.

    Short wobbles show up here even when averages look fine.

Can this help me?

Yes, if the problem comes and goes instead of being slow all the time.

Why would I use this?
Steady timing keeps voices and video smooth.
When should I use this?
Use it when calls stutter even though your speed looks fine.
What will I learn?
You learn how steady your connection is over a short window.

What it will not tell you: It cannot tell you what caused the unsteadiness, only that it is there.

Start here

Nothing happens until you press start.

How healthy is your internet?

Test your speed. Understand your connection. Know what to do next.

Your IP address is sent to Measurement Lab and published in their open dataset.

  • No account required
  • Takes about 20 seconds
  • Powered by Measurement Lab

What does this mean for me?

Here is how to read the numbers you get back.

  • The number shows how much the answer time changes from one moment to the next.
  • A small number means your connection keeps a steady rhythm.
  • A large number means the timing wobbles, and live voices suffer first.

Everyday use

Sizes and speeds are easier to judge with a familiar example.

  • A clear video call

    Calls usually stay smooth when jitter stays below about 15 ms.

  • A laptop far from the router

    Distance and interference are common reasons timing varies.

What should I do?

  1. Move closer to your router, or remove what sits between you and it.
  2. Pause big downloads and backups, then test again.
  3. Try a cable to see whether wireless is the unsteady part.

What happens if I ignore this?

If you do nothing, live calls stay the first thing to suffer.

Check if this is the problem

Run a self-check when you want to test one change at a time.

Check this yourself

Common questions

What are the limits of this test?
It samples a short window, so it can miss rare spikes.
Does jitter prove my Wi-Fi is the problem?
No. It shows variation, not where the variation came from.

Learn more

These articles explain the idea behind this tool.

Technical details

The words behind the numbers, in case you want them. You do not need any of this to use the tool.

Jitter
How much the answer time varies between one message and the next.
Interference
Other signals nearby making a wireless connection less reliable.

What you get back

  • Jitter (ms) — Variation in round-trip time.
  • Samples used — How many probes were counted.

Norynt writes its own explanations. External documentation is listed only so you can verify what you read here.

Technical references

The information in this article is based on publicly available technical documentation and networking research. You do not need to read any of it to understand the article.

Measurement Lab(1)

The open measurement platform Norynt runs its speed tests on.

RFCs(1)

The formal internet standards behind these terms.