Tippy Tipper is an open-source tip calculator available for Android devices. The app is designed to make calculating tips a breeze by providing a simple and easy-to-use interface. It allows you to enter the bill amount via a custom keypad and select the tip percentage by using a slider or three configurable buttons. You can also round up or down by tip or total, and even split the bill.

One of the most useful features of Tippy Tipper is the ability to exclude tax rates. This feature is great for those who want to calculate the tip based on the subtotal, rather than the total bill amount. The app is free to use, but the developer encourages users to purchase the donate version if they find the app useful. Additionally, the developer welcomes patches from users who want to contribute to the app's development.

Overall, Tippy Tipper is a simple and effective solution for anyone who needs to calculate tips quickly and easily. Its open-source nature and customizable features make it a great choice for anyone looking for a tip calculator app.