FINANCIAL: future value, present value, interest, payment, duration.
SCIENTIFIC: logarithms, powers, exponentials, factorials, roots, NIST/CODATA scientific constants.
CONVERSIONS: over forty categories of units from the common (length, volume, mass) to the technically advanced (electric charge, entropy, viscosity). Meter to foot, ounce to gram, liter to pint, day to minute, C to F...
DATE AND TIME: add or subtract periods to a date/time, find the difference between two dates/times.
NUMERIC BASES: binary, octal, hexadecimal, all bases from 2 to 36, simple notation.
BIT-LEVEL/BINARY: binary AND, OR, NOT, XOR, SHIFT and more.
COMPLEX NUMBERS: natively supported plus functions (argument, norm, polar, imaginary, more).
PRIME NUMBERS: verify primeness, identify next or previous prime.
RANDOM NUMBERS: real or complex, linear or Gaussian.
RATIONAL and FRACTIONAL numbers: input and output using ratios.
GENERAL MATHEMATICS: modulo, remainder, percent, factorial, rounding, ceiling, floor...
STATISTICS: group attributes (maximum, greatest common denominator, least common multiple, more) and distribution (variance, standard deviation, median, more).
HYPERBOLIC and TRIGONOMETRY: sine, cosine, tangent, cotangent, secant, cosecant, inverse functions.
QUICK ACCESS: on/off mode, selectable hotkey and shortcuts on task bar, desktop or start menu.
PREFERENCES: selectable keypads, adjustable button size, selectable font, top-level mode, Num-Lock, snap to screen position, switchable decimal mark.
NUMERIC FORMATS: scientific (1.23e-45), currency (12,345.00), fractional (1 2/3) and more, each format is customizable.
EDITABLE WORK AREA: better than a regular tape calculator. Enter full expressions, change the numbers, repeat any calculation. Annotate your work like a regular text editor. Save to file for later use as text (.txt) or rich-edit (.rtf) document. Restore saved work.
DETAILED HELP FILE explains all features.
Visit the Orefa.com web site and take a look at the "related" pages: the list of awards is very impressive. This is quality software.