ShpeedTT's Calculator is a free calculator app for Android devices that provides an easy-to-use interface and a range of scientific functions. The app has big digits and can display one to five lines of calculation to make it easier to read and understand. It also comes with a dark theme, making it easy on the eyes.

One of the standout features of the app is the ability to shake the device to change colors. Additionally, the app offers instant results and the ability to copy the result. The history function is another great feature, saving every operation so that you can select it later. Moreover, the app supports operations with big numbers and percentage functions.

You can customize the app to your liking by changing the order of the function buttons, setting the decimal number for the result, and changing the number format. The app also comes with memory functions and displays what is saved in memory at any moment. Finally, the app supports sounds, making it easier to use.

Overall, ShpeedTT's Calculator is a great app for anyone looking for a free calculator with scientific functions. It has a range of useful features and is easy to use.