Sets the initial scale for this WebView. 0 means default. The behavior for the default scale depends on the state of WebSettings.UseWideViewPort and WebSettings.LoadWithOverviewMode. If the content fits into the WebView control by width, then the zoom is set to 100%. For wide content, the behavor depends on the state of WebSettings.LoadWithOverviewMode. If its value is true, the content will be zoomed out to be fit by width into the WebView control, otherwise not. If initial scale is greater than 0, WebView starts with this value as initial scale. Please note that unlike the scale properties in the viewport meta tag, this method doesn't take the screen density into account.

[Android Documentation]