As much as it would cost a native app. Say, on Mac, a plain AppKit app consumes 16-17 MB, gea consumes 18-20 MB, Qt consumes 25-35 (depending on whether you use QML or not) and Tauri consumes 58-60 MB. Tauri suffers a lot from all the WebKit dependencies, as its UI is not native but rather HTML rendered by WebKit.