The first step in using CalcTastic is knowing how to navigate around the application. At the top-left of the app, you’ll find the menu button which will open the main or left-menu. Once the menu is open, the icon turns into an arrow (pointing left) which will close the menu.

From the left-menu, you can choose your calculator mode, basic, scientific or programmer. Scientific and Programmer are entirely separate calculators, each with its own history and memory. Basic is the same as Scientific with fewer buttons. If you are using the Free Version, you will not have access to the programmer’s mode.

Below the mode selection are some general features including a settings menu, a help link and a dialog that will display some basic information about CalcTastic.


The other important area for navigation is the top-menu. This bar at the top will have quick access to some important features, including your history, and the full stack for RPN users.

  • If you are in the basic mode, there will be a button for unit conversions.
  • If you are in the programmer mode, there will be a button to toggle the dedicated binary bit display.
  • If you are in the scientific mode, there’s an addition drop-down by pressing the right-most button that looks like three dots.


In algebraic mode (which is the default), you will see an equation screen above the keyboard. Your current equation will be displayed here, and the result will update automatically as you type.

You can move the cursor left and right with the arrow keys or simply touch a spot in the equation to move it there. The cursor cannot be dragged though.

There is also an intermediate value (the current operand) that will display in the top bar (above the screen). As you type or move the cursor, this value will also update automatically.

The current operand is the value that is operated on in many cases (i.e. unit conversions, memory operations, etc).

Notice in the screenshot below (with the cursor next to the ), the current operand shows a value of 49 and the current result in progress shows 49.5, which is faded a little indicating we haven’t pressed = yet.

Previous calculations will show (in order) above the current one. At any time, you can press CLS to clear the screen. After clearing the screen, you can still access your previous calculations by clicking the history button (Clock) in the top bar. Here’s what that pop-up looks like. Notice there’s an indicator ▼ ON SCREEN ▼ showing everything that’s still on-screen.

* All screens and pop-ups will let you touch one of the previous values to drop it into your current equation.

* At the top-right of most pop-up screens, there’s a reminder of what notation and precision you currently have set. At the default settings, this will read STD:12 for Standard Notation and 12-digit Precision.

If you are in programmer mode, this will instead show your current base and integer-size. At the default settings, this will read DEC:S64 for Decimal and Signed-64.


In RPN mode (selectable in the settings), you will see the stack screen above the keyboard. The top bar will show the number of items on the stack. For buffered RPN, the buffer does not count as a stack entry. The keyboard is also a bit different in buffered RPN because you don’t need a DROP button. Instead, ROLL▲ gets its own dedicated button.


CalcTastic has 10 memory registers for each mode, scientific and programmer. The positions are labeled M and then 1-9. The MS and MR buttons will save or recall a value, respectively. The value used by the MS button depends on your input type:

  • RPN – It is always your bottom most stack entry (buffer included).
  • Algebraic – It is your current operand (see above) for an equation in progress, or the result for a completed one.

The M-position is unique in the following ways:

  • The M+, M− and MC buttons will add-to, subtract-from and clear the M-position.
  • If the M register is empty, pressing MS will auto-save your value there. Otherwise, it will ask you which register you want to save to.
  • If the M register is the only one saved, pressing MR will auto-select that one. Otherwise, it will ask you which register you want to choose from.

* When the M-position register has a value saved, the letters MS in the MS button will be highlighted.


All the screens and pop-ups in CalcTastic have contextual menus that you can trigger by long-pressing on one of the values in the list. This will bring up options like copy, paste, remove, etc.

The items in the context menus won’t always be identical, as they are location based. For example, paste will come up at the bottom row (current equation) of the equation screen but not on the second row. Here is an example screenshot: