Some free digital scale apps are Balance Scale for iOS and Mobile Digital Scale Lite for Android. Balance Scale offers passcode protection and displays weight in both the U.S. system and the metric system. It also features a converter that allows the user to convert between the systems easily.
Mobile Digital Scale Lite displays a realistic weight bounce when the users places an object on his phone. It displays weights in both the U.S. system and the metric system, and allows the user to calibrate the scale. It also lets the user reset the scale to zero. This free app contains advertisements, and the user has the option to purchase an ad-free version.