Aquarius Soft PC Binary Converter
Aquarius Soft PC Binary Converter is a simple and fast number system conversion software that lets you instantly convert between binary, octal, decimal and hexadecimal number systems. Simply enter a value into one of the edit box and immediately see the results in the other 3 edit boxes. ... Aquarius Soft PC Binary Converter features include: -Immediate conversion between the 4 number systems: binary, octal, decimal, and hexadecimal. ... -Allow you to arrange the top to bottom order of the 4 number systems.
http://www.aquariussoft.com/downloads/asbc1_00.exe - 812Kb - Download - Screenshot

KidsMath
This is a small calculator that will stay on top all the time while your working. Converts Decimal to Hex, Binary, and returns Ascii characters. All keys have tool tip text to easily find keyboard shortcuts.
http://home.comcast.net/~jlebr549/KidsMath.msi - 527Kb - Download - Screenshot

pmaCalc
pmaCalc combines a scientific calculator, binary arithmetik for programmers, and unit converter in an interesting package. In addition to a fair range of scientific functions, it has an unusual numeric stack, and a binary mode that supports decimal, hexadecimal, octal, and binary arithmetic,... You can enter expressions by pressing buttons or by typing them in (it's advisable to take care with the syntax), and the stack offers a flexible alternative to the usual memory functions. ... You can use fixed,floating and sci.
http://www.pmasoft.net/download/pmacalc.exe - 639Kb - Download - Screenshot

EditAll
EditAll is a file editor on the level of the bits and bytes. This is useful if you have no other suitable editor or viewer available for a specific data format. The content of a file can be displayed and edited in various data formats: signed and unsigned integers of 8, 16, and 32 bits, and... In order to allow other applications, such as Notepad, to receive text data from EditAll, there is an option to copy text adapted for that purpose. ... Data copied to the clipboard can be copied to another file by opening that file in a second instance of EditAll.
http://www.palmwood-software.com/EditAllEvaluationSetup.exe - 601Kb - Download - Screenshot

Groovy Hex Editor
Groovy Hex Editor is a tool for editing binary formats. I've paid particular attention to making it colorful and easy to use and tried to give it a cool looking color scheme (hence the name "groovy" hex editor). You can also downgrade it to a "standard" windows color scheme if thats more to your... You can toggle the display between hex and decimal, and there is a built in inspector that easily lets you see the hex, decimal, and binary equivalents of a group of bytes at once. ... There's even a changelog that lets you keep track of what modifications you've made to the current file.
http://www.sb-software.com/hexeditor/sbhexd15.exe - 1Mb - Download - Screenshot

2002 Lucky Calculator
Lucky - A compact and powerful calculator that supports skins. It also supports four notations: decimal, hexadecimal, octal, and binary. It contains 50 built-in functions. Calculates an expression without pressing any additional buttons or keys. The history contain list of calculated expressions. ... Automatic clipboard copy. ... The icon is minimized in the system tray and can be called up by a hotkey.
http://www.zslab.com/products/Lucky15.exe - 363Kb - Download - Screenshot

CalculatorX
CalculatorX is an enhanced expression calculator. It can evaluate an expression for one time. You can use Arithmetic, Logic, Bitwise and Relation operations in your expression. And many system constants and built-in functions can also be used in the expression. ... You can use Binary, Octal, Decimal and HEXadecimal numbers in one expression to evaluate as well. ... You can add your own functions to CalculatorX in order to convenience your work. ... CalculatorX is powerful, but it is very easy to use.
http://www.xoyosoft.com/cx/download/CalcX.zip - 1Mb - Download - Screenshot

Hex Editor Delphi 5 Control
The Hex Editor Control is a powerful tool allows the user to viewing and editing any sort of binary data files in hexadecimal, decimal or binary form. It has been designed to be used inside VC++, VB or Delphi applications and on web pages as well. ActiveX and Delphi 5 versions are available.
http://elra-co.virtualave.net/hexeditd.zip - 151Kb - Download - Screenshot

Hex Editor ActiveX Control
The Hex Editor Control is a powerful tool allows the user to viewing and editing any sort of binary data files in hexadecimal, decimal or binary form. It has been designed to be used inside VC++, VB or Delphi applications and on web pages as well. ActiveX and Delphi 5 versions are available.
http://elra-co.virtualave.net/hexeditx.zip - 291Kb - Download - Screenshot

PalmaryCalc
PalmaryCalc is a calculator with a user-friendly interface. It is all in one: from a simple calculator to a scientific, conversion functions (from cooking to astronomical), credit, base number conversions between binary, octal, decimal, and hexadecimal; 32-bit, 16-bit, and 8-bit integer math... The variety of input methods (including RPN) enables you to perform almost all operations you need.
http://www.palmarysoft.com/products/calc/PalmaryCalc_v101.zip - 625Kb - Download - Screenshot