Jitter & Shimmer Calculator
Jitter and shimmer are classic acoustic perturbation measures. Jitter reflects cycle-to-cycle variation in fundamental frequency, while shimmer reflects cycle-to-cycle variation in amplitude. Elevated values are associated with roughness and hoarseness and are commonly reported in clinical voice assessment.
Open the Jitter & Shimmer Calculator →How to measure jitter and shimmer
Record a steady sustained vowel (for example /a/) in a quiet room. Vocametrix extracts the perturbation measures automatically and lets you export them, so you can document vocal stability over time.
Interpreting the values
Jitter and shimmer require a reliably periodic signal, so they are most meaningful on mild-to-moderate dysphonia and sustained vowels. For more severe voices, robust measures such as CPP or AVQI are often preferred.
Reference values for jitter and shimmer
The figures most often quoted are 1.04% for local jitter and 3.81% for local shimmer. They come from the MDVP software and were not validated for Praat, which gives lower values (Praat manual; Keung et al. 2024). Older men without a voice disorder average 4.4% shimmer (Banh et al. 2009). To our knowledge, no validated cutoff exists for jitter and shimmer computed by Praat.
Frequently asked questions
What recording do I need for jitter and shimmer?
A stable, sustained vowel recorded in quiet conditions gives the most reliable jitter and shimmer values.
Is this an alternative to Praat for jitter/shimmer?
Yes. Vocametrix computes jitter and shimmer online without requiring you to install Praat or write scripts.