This app lets you type in various weights of karat gold, and it totals it up for you at the bottom right of the screen. You can change the percent "payout" at the bottom by changing the percentage at the bottom left of the screen. It's perfect for jewelry stores, pawn shops, and gold buyers. It's very simple and easy to use. The gold price is refreshed automatically when you re-open the app. The percentage is also saved even when you close the app.

Example of use: