CustomCalc is a free, easy-to-use, and fully customizable calculator. It is an alternative to the built-in scientific and financial calculators on the iPhone and other iOS devices.

With CustomCalc, you can calculate many different types of values, including fractions, decimals, percents, and more. It also has a built-in unit converter that allows you to convert from one unit to another, and it can automatically update the conversion rate for you.

The app also has a built-in currency converter that lets you convert from one currency to another, and it has a built-in date and time converter that lets you convert from one date and time to another.

You can also customize the keyboard to suit your needs. You can change the font, color, and size of the keys and the buttons. You can also change the layout of the keys. You can even add a new key that allows you to input binary values.