Select an image to measure its blur. It will only be processed in your browser, not uploaded anywhere. Your browser needs to support ES2015 modules in web workers.
The used algorithm is loosely based on the 2002 paper "A no-reference perceptual blur metric" by Pina Marziliano, Frederic Dufaux, Stefan Winkler, and Touradj Ebrahimi.
Visit the GitHub project to see the code, this blog post describing how it works, or the author's homepage.