CLP's Nice Calculator

This is an RPN, or stack-based, calculator. You put numbers on the stack, and then you do things to them.

For example, to work out 1 + 3, you'd:

  1. Type 1
  2. Press Enter
  3. Type 3
  4. Press Enter
  5. Press +

It's a different way of doing things to a normal calculator, but it can be much more efficient for complicated calculations.

This calculator not only displays the results of calculations, but shows you what went into producing them.

The display shows the current stack. Input numbers are shown in blue, and operations are shown in yellow.

Type a number and press Enter to push it onto the stack.

You can tap any item on the stack to select it, or use the arrow keys to move the selection.

When you push a number, it's inserted below the selected item.

Input numbers inside an operation can't be deleted, but they can be changed, moved or copied.

To change a number inside an operation, select it, type the new value, and press Enter.

When you copy a number, it's given a label to identify it. If you change the value of the number, it changes in all the copies too.

Nested operations are folded up by default. Click on an operation to unfold it and see what's inside.

Command Key
Shift Tab Switch to the next screen of buttons.
Drop Delete Remove the selected item from the stack.
Swap w The selected item and the one above it exchange places.
Copy d Add a copy of the selected item to the bottom of the stack. Copies of the same number are linked - if you change the value for one, it changes in all the copies too.
Undo u When you've selected an operation, undo it and leave its arguments in place on the stack.