The pediatric calculator for Android
The pediatric calculator for iPhone and iPad
The pediatric calculator for Windows Phone
Works with almost every device (needs internet connection)
Ped(z) - Pediatric Calculator as an app for Android and iPhone/iPad is available for free. The features of the app are the same as in the website (except for the plotter, which is missing in the app).
There is also an untested version for Windows Phone. It is available on Request at the author.