Kalkulilo Calculator is a comprehensive productivity app designed for iPhone users, featuring a variety of modes to cater to different calculation needs. It includes a scientific mode with standard arithmetic operations, trigonometry functions, and advanced features like logarithms and roots. Additionally, the app offers a bit/integer mode for logical operations and supports calculations in multiple numerical bases, from binary to hexadecimal.

The app also excels in statistical calculations, allowing users to compute mean, median, variance, and more. A time mode is included for handling time values, while a simple calculator mode provides basic operations with an intuitive interface. Users can customize the app's appearance, and it also features a widget for quick access in the notification center, along with compatibility for Apple Watch. While ads support the app's development, users can opt for an in-app purchase to remove them.