True Jitter Calculator (RFC 3550)
Measure real jitter — the variation between consecutive packets, not deviation from the average.
How this reads your output
Paste the full output of a ping run and the per-packet reply times are extracted, then the absolute difference between each packet and the one before it is averaged. That average is jitter as RFC 3550 defines it. Linux ping prints mdev instead, which averages each packet’s distance from the overall mean, so the two figures differ on exactly the connections where it matters most. Both are shown side by side.
What the results mean
- Jitter (RFC 3550)
- The mean difference between consecutive packets. Under 10 ms is comfortable, 10–30 ms is audible on calls, and above 30 ms breaks voice and gaming.
- mdev
- Mean deviation from the average round trip, which is what Linux ping reports. It is a useful number but it is not jitter, and a connection alternating between 10 ms and 100 ms has low mdev and terrible jitter.
- Packets analysed
- How many per-packet lines were found. Below 20, the result is indicative only — Windows sends 4 by default.
- Spread
- The gap between the fastest and slowest packet. A large spread with low jitter means one outlier rather than sustained instability.
Common problems and fixes
- The tool says it found no reply lines
- Paste the whole run, not just the summary. Jitter is calculated from the individual per-packet lines, and the min/avg/max summary does not contain them.
- The jitter figure does not match what my terminal printed
- Your terminal almost certainly printed mdev, which is a different calculation. Both are shown here so you can compare them directly.
Frequently asked questions
Why does this differ from the jitter my router or speed test reports?
Most consumer tools report mdev, or a smoothed average, and label it jitter. RFC 3550 defines jitter as the mean absolute difference between consecutive packets, which is what governs whether a voice codec can hide the variation. This tool uses that definition and shows mdev alongside it so the difference is visible.
How many packets should I send?
At least 50. Use ping -n 50 on Windows or ping -c 50 on macOS and Linux. Four packets, the Windows default, is far too few — a single delayed packet distorts the result entirely.
Is my pasted output sent anywhere?
No. The parsing happens in your browser with no network request. Ping output can contain your public IP and internal hostnames, which is exactly why it is not transmitted.