A good question. Well, a $10 drugstore-brand camera also takes pictures... The list below should, I hope, satisfy your curiosity; it should also help you to compare Kalkulator with any other program of this kind.

• The user may switch between a number of expressions without reentering them.
• If a syntax error is detected, the cursor will be placed right at the offending symbol and you will be able to fix the problem without retyping of the whole expression.
• All computational errors are trapped: in the worst case you get a diagnostic message, not just an "E----" display.

• 39 "standard" functions: logarithmic and exponential (base e, 10 and 2), trigonometric and inverse, hyperbolic and inverse, square, cube, and corresponding roots, plus some handy utility functions (fractional part, absolute value, etc.)
• 4 Euler (or related) functions: gamma, logarithmic gamma, beta, combinations. The factorial operator, !, is also provided.
• 44 statistical distribution functions for eight most common distributions; this includes not just distribution densities but also left, right, and central distribution integrals and functions inverse to these integrals, commonly used in statistics and never provided in calculators.
• 3 random number generators: uniform, Normal and Poisson.
• 3 conditional functions, selecting the second or third argument depending on the sign of the first argument.
• 3 mixed-unit entry functions: lb/oz, ft/in, hrs/min/sec.
• 12 user-defined functions (of up to four arguments).

• Fixed- and floating-point with a selectable number of digits (also a default format, based on the displayed value)
• Whole part and fraction, e.g., "6 2/9"
• Pounds, ounces and fraction, e.g., "4 7 9/16"
• Feet, inches and fraction, similar to the above
• Degrees, minutes and seconds of angle
• Decimal degrees of angle (same for minutes and seconds)
• Hours, minutes and seconds of time, e.g. "12:31:29"

Any calculation result can be converted between different measurement units. Conversions for area, energy, force, length, mass, power, pressure, speed, temperature, time, and volume are provided.

The program allows you also to recall the values of a number of popular physical constants (or any other constants you may wish to define).

Both units and physical constants are user-configurable, being defined in separate text files.

• Numerical integration over a given interval
• Computing a derivative at a given point
• Computing a sum within given argument limits and with a given step
• Finding a zero point, i.e., solving an equation f(x)=0, within a given interval

• A number of functions can be plotted within a single graph, either by adding a them one by one to the graph canvas or simultaneously.
• The y-range can be entered manually or computed (and rounded) by the program. For multiple plots the joint range can be computed.
• The algorithm makes necessary adjustments for the local line curvature and properly handles discontinouities.
• There is an option to include the coordinate grid.
• Mouse coordinates can be read out and saved into variables.
• Graphs can be copied to Windows clipboard for use with other programs.

• 16 arithmetic operators, including shift and rotation, bit set/reset, AND, OR, exclusive OR, etc.
• 8-, 16-, and 32-bit word length
• Binary, octal, hexadecimal, and decimal data format and input
• Unsigned and signed (two's complement) arithmetic modes
• Stack maniulation, ten memory registers

• Computing the population parameters: mean, variance, standard deviation, minimum and maximum values, covariance (if applicable)
• Drawing a data histogram of X points
• Drawing a scatter plot of XY points, computing polynomial regression coefficients and adding the regression line to the plot
• Computing the values of test statistics ("goodness of fit"):
• For a set of XY points and a given x-y function: sum of squared or absolute deviations
• For a sample of X points and a given distribution density function: chi-square or likelihood value
• The X and/or Y values can be, in a wholesale fashion, computed using any formula (which may refer to other values in the buffer).
• The data buffer values and computed parameters can be used in any Kalkulator expressions.

• For a set of XY points it finds the values of parameters p1..pn for which the regression function y = f(x|p1..pn) fits the points best in terms of minimum squared or absolute deviations.
• For a population of X points it finds the combination of p1..pn for which the distribution density f(x|p1..pn) fits the population distribution best in terms of minimum chi-square or maximum likelihood. The shape of f(x) does not have to be chosen from a predefined set; any analytical formula will be accepted. Now, if you had any doubts who's the king of the hill...

• Addition and subtraction of vectors or matrices
• Matrix, vector, and scalar multiplication (any combination of operands)
• Dot product, cross product
• Matrix transposition
• Matrix inversion
• Solving systems of simultaneous linear equations
• A spreadsheet-like editor for matrices and vectors is provided.
• All elements of a matrix (or a vector) can be defined with a single expression using the index value(s) as parameter(s).