Misophonia is a sound sensitivity disorder characterized by a strong aversion to specific sounds (e.g., chewing). Here we present the Sussex Misophonia Scale for Adults ( SMS-Adult), within an online open-access portal, with automated scoring and results that can be shared ethically with users and professionals. Receiver operator characteristics show our questionnaire to be “excellent” and “good-to-excellent” at classifying misophonia, both when dividing our n = 501 adult participants by recruitment stream (self-declared misophonics vs. general population), and again when dividing them with by a prior measure of misophonia (as misophonics vs. non-misophonics). Factor analyses identified a five-factor structure in our 39 Likert-type items, and these were Feelings/Isolation, Life consequences, Intersocial reactivity, Avoidance/Repulsion, and Pain. Our measure also elicits misophonia triggers, each rated for their commonness in misophonia. We offer our open-access online tool for wider use ( www.misophonia-hub.org ), embedded within a well-stocked library of resources for misophonics, researchers, and clinicians.