RPN Calculator

PCalc is the powerful choice for scientists, engineers, students, programmers, or indeed anybody looking for a feature rich calculator. It includes an optional RPN mode and multi-line display, a choice of button layouts, an extensive set of unit conversions and constants, a paper tape, multiple undo and redo, engineering and scientific notation, as well as support for hexadecimal, octal, and binary calculations.

Release notes: You can now create your own conversions and functions with a powerful built-in editor.
User conversions and functions can be shared with other people, and are synced across multiple devices automatically using iCloud.
Updated built-in scientific constants to 2010 values from CODATA.
Added an option to show the live result of the last function used on a line of the display.
Fixed a problem drawing the ticker tape with custom display colours.
Fixed a problem editing user constants in landscape mode.
Fixed a problem with thousands separators not appearing when you copy or email the tape.
Fixed a problem with the engineering display mode.
Fixed a problem with external hardware keyboards input not working.
Fixed a problem starting up on an upside down iPad.