Jitter Calculator
Calculate network jitter as the variation in packet delay across a sample.
About Jitter Calculator
Jitter is the variation in packet delay over time, not the delay itself. The simplest measure is the average absolute difference between consecutive latency samples. RTP-based systems (VoIP, video) commonly use the RFC 3550 exponentially-smoothed estimator, J = J + (|D| − J)/16, where D is the difference between consecutive transit times, which reacts gradually to give a stable running estimate that's less sensitive to single outliers.
Formulas
Simple average jitter
jitter = average(|latency[i] − latency[i-1]|) for consecutive samples
- L_i
- The i-th latency measurement
- n
- Number of measurements
RFC 3550 smoothed jitter
J = J + (|D| − J) / 16
- D
- Difference in transit time between two consecutive packets
Worked example
With the default values below, Jitter Calculator returns Average Jitter of 4.333. Change any input above and every figure here is recalculated in your browser.
Inputs used
- Latency Measurements
- 45, 48, 46, 52, 44, 49, 47
Results
- Average Jitter
- 4.333 ms
- RFC 3550 Smoothed Jitter
- 1.399 ms
- Max Jitter (Single Step)
- 8.000 ms
- Mean Latency
- 47.286 ms
Step by step
- 1Values used
- 2Simple average jitter
- 3RFC 3550 smoothed jitter
- 4Average Jitter= 4.333 ms
- 5RFC 3550 Smoothed Jitter= 1.399 ms
- 6Max Jitter (Single Step)= 8.000 ms
- 7Mean Latency= 47.286 ms
Assumptions and limits
- The result is derived only from the single input listed above. Anything not among them is not part of the calculation.
- In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
- Figures are rounded for display to 3 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.
Frequently Asked Questions
How is jitter different from latency?
Latency is how long a single packet takes to arrive. Jitter is how much that delay varies from packet to packet. A link can have high latency but low jitter (consistently slow) or low latency but high jitter (usually fast, occasionally spikes).
Why does jitter matter for VoIP and video calls?
Real-time audio/video is played out at a fixed rate. If packet delay varies too much, the playout buffer either runs dry (causing gaps/glitches) or overflows, so high jitter causes choppy audio and video even without any packet loss.
What jitter value is considered good for VoIP?
Under about 30ms of jitter is generally considered good for VoIP; above that, call quality noticeably degrades unless the jitter buffer is enlarged, which in turn adds more latency.
Why use the RFC 3550 smoothed formula instead of a simple average?
The RFC 3550 estimator weights recent samples more heavily and updates continuously, so it responds to real trends in network conditions without being thrown off by a single one-off delay spike the way a simple average of all samples can be.