kalker is described as 'A calculator with syntax highlighting that supports user-defined variables and functions, math-like syntax, and some more advanced operations such as derivation and integration (estimate), and complex numbers' and is an app in the Education & Reference category. There are more than 10 alternatives to kalker for a variety of platforms, including Windows, Linux, Online / Web-based, Android and iPhone. The best alternative is SpeedCrunch, which is both free and Open Source. Other great apps like kalker are Wolfram Alpha (Freemium), Qalculate! (Free, Open Source), Windows Calculator (Free, Open Source) and Insect (Free, Open Source).
SpeedCrunch is a free, fast, high precision open source algebraic calculator with an intuitive interface and a extensive list of features, including: Unlimited Variables, Syntax Highlighting, Functions, with 'Automagic' Completion, 50 Decimal...
Wolfram Alpha is a "Computational Knowledge Engine" - different from a search engine, it answers factual queries directly by computing the answer from structured data, rather than providing a list of documents or web pages that might contain the answer.
Qalculate! is a multi-purpose cross-platform desktop calculator. It is simple to use but provides power and versatility normally reserved for complicated math packages, as well as useful tools for everyday needs (such as currency conversion and percent calculation).
A simple yet powerful calculator that includes standard, scientific, and programmer modes, as well as a unit converter. It's the perfect tool to add up a bill, convert measurements in a recipe or other project, or complete complex math, algebra, or geometry problems.
High precision scientific calculator with full support for physical units. - Evaluation of mathematical expressions - Parsing and handling of physical units (All SI units, imperial units, time-based units, ..
Equalizer is a freeware scientific calculator. Instead of the traditional look of many buttons, Equalizer has a simple text line on which you can write the expression in the same way you'd write it on paper, and drawing graphs of equations.
Supercalc is an expression calculator for Windows. An expression calculator gives the user the ability to type an equation exactly as it is to be evaluated. This allows for much more intuitive use of the calculator.