If you're looking for evidence that Microsoft has gone over every single detail in Windows 7 with the proverbial fine-toothed comb, look no further than Calculator, an applet that dates back to the very first version of Windows from 1985. The user experience of this utilitarian applet wasn't significantly updated in decades, and indeed, a quick look at the Calculator application from Windows 2000 (1999), XP (2001) and Windows Vista (2006) reveals that they are, in fact, identical aside from the look and feel of the OSes themselves.

Windows 7 Feature Focus: Calculator
Calculator, as seen in Windows 2000, XP, and Vista (from left to right).

Windows 7 Feature Focus: Calculator
The new Windows 7 Calculator.

Secret: OK, the Windows Vista version of Calculator was, in fact, updated by the same team responsible for Windows Sidebar, Texas Hold 'Em, and various other system utilities like Notepad and Paint, but that was mostly to ensure that it worked with Aero glass and offered some modicum of high DPI support. The actual functionality of Calculator remained largely unchanged.

Update: Microsoft uber-programmer Raymond Chen has a nice blog post describing changes to the applications internal calculation engine over time.

In Windows 7, Calculator gets a surprisingly major update and the first serious functional refresh since Windows 95. For the first time since that release, Calculator gets a new default layout, and in this release, the applet has been significantly resized so that it will work better with a coming generation of multi-touch-compatible displays. (That's right: For the first time, a significant percentage of Windows users will actually be able to "press" the Calculator buttons with their own fingers, as we do with physical calculators.)

But the biggest change in the Windows 7 version of Calculator is that it now supports different modes of operation. And within these modes, you can also configure Calculator to expand to display additional functionality, including some useful new worksheets.

Calculator modes

The Windows 7 Calculator modes include:

Standard. This is the classic Windows Calculator and works largely like all of the Calculator versions included with Windows 95 through Windows Vista. One change is that in addition to the Memory Clear (MC), Memory Recall (MR), Memory Store (MS), and Memory Add (M+) buttons, the Windows 7 version of Calculator adds a Memory Subtract (M-) button.

Scientific. As with previous Windows versions, the Windows 7 Calculator includes a Scientific Calculator mode as well.

Windows 7 Feature Focus: Calculator
Calculator in Scientific mode.

Programmer. New to the Windows 7 Calculator is a Programmer mode that provides such things as number format conversion (hexadecimal, decimal, octal, binary), data type conversion (BYTE, WORD, DWORD, QWORD) and the like.

Windows 7 Feature Focus: Calculator
The new Programmer mode.

Statistics. Also new to the Windows 7 Calculator is a new Statistics mode.

Windows 7 Feature Focus: Calculator
The new Statistics mode.

Each of these modes requires a certain bit of expertise as Calculator provides little or no explanation for how these modes can be used or what the purpose of various buttons is.

Tip: What's missing from Calculator are tooltips: It'd be nice to be able to hover over any one of the hundreds of buttons this applet now provides and receive a tooltip explaining its functionality. Just a thought.

Additional Calculator functionality

You can also access additional Windows 7 Calculator functionality via the View menu. This functionality includes:

Basic. In this display, Calculator includes only those buttons required by the current mode.

Unit Conversion. When enabled, Calculator expands to the right and provides angle, area, energy, length, power, pressure, temperature, time, velocity, volume, and weight/mass conversion functionality. Each offers unit-specific options. For example, with temperature, you can convert to and from Celsius, Fahrenheit, and Kelvin; and Area supports to and from conversion of acres, hectares, square centimeter, square feet, square inch, square kilometer, square meters, square mile, square millimeter, and square yard.

Windows 7 Feature Focus: Calculator
Here, we're converting from Celsius to Fahrenheit.

Date Calculation. In this display, Calculator provides various date/time calculations, including the difference between two dates and adding or subtracting days to a specific date.

Worksheets. Calculator offers a number of worksheets, including Mortgage, Vehicle lease, Fuel economy (mph), and Fuel economy (L/100 km). Each of these worksheets is customized for the task at hand. Fuel economy (mph), for example, provides entry fields for distance, fuel used, and fuel economy; fill in two, and the third will be calculated.

Windows 7 Feature Focus: Calculator
Calculating fuel economy.

Secret: If you're a Windows XP or Vista user and would like a better calculator application, check out Microsoft Calculator Plus and the XP Power Toy Power Calculator, both of which are free downloads. Each offers some unique features, including some functionality that isn't even in the Windows 7 Calculator.

Final thoughts

While Calculator can hardly be called a tier-one Windows feature, the sheer number of functional additions to this handy little applet is somewhat inspiring. (And you have to think Apple would have counted every single change as a new feature had this application appeared in Mac OS X.) While most Windows users probably give Calculator little attention, you may want to take a deeper dive this time around, as there's a lot going on here.