netutilus

Jitter

Jitter is how much the delay varies from one packet to the next. A connection can be fast and still stutter on calls because of it. Here is what causes it and how to measure yours with Netutilus for Mac.

Download on the Mac App Store ↗

free to download · macOS 14.6 or later

Jitter is how much the delay changes between one packet and the next. A connection that answers in 30, 31, 29 and 30 ms has almost none. One that answers in 20, 90, 25 and 70 ms has a lot, even though its average is no worse.

Why it matters

Calls, video and games send a steady stream of small packets. When they arrive unevenly, the app has to wait for late ones, or drop them. You hear it as choppy audio and robotic voices, and see it as frozen video. Downloads and web pages hardly notice.

What’s good

  • Under 5 ms: excellent.
  • 5 to 20 ms: fine for most calls.
  • Over 20 ms: calls start to break up.

Netutilus works jitter out from consecutive answers: the average step from one to the next. A lost probe is skipped, not counted as a jump. MTR’s Stdev column measures much the same thing per hop.

Where it comes from

  • Wi-Fi interference: other networks, microwaves, a weak signal. Compare with a cable.
  • A busy line: when uploads or downloads fill it, the router’s queues make the delay jump. See bufferbloat.
  • A struggling link further away: check where it starts in MTR.

Run it on your own network

Netutilus puts every network tool in one app. Free to download; Pro is a one-time purchase, never a subscription.

Download on the Mac App Store ↗

More in learn

  • BufferbloatWhy the delay shoots up while your line is busy, and how to fix it on the router.
  • CertificatesHow a website proves who it is, and why a connection sometimes isn't trusted.
  • DNSThe internet's address book, which turns names like example.com into addresses.
  • Hops and TTLHow traffic crosses the internet one router at a time, and how traceroute finds each one.
  • ICMP and TCP PingTwo ways to time a host, and why one may answer when the other doesn't.
  • IP AddressesThe numbers devices are reached by: public and private, IPv4 and IPv6.