Did you know that LT has had a built-in calculator since LT 2006? It's called QuickCalc, and it's a palette-based calculator with all sorts of functions.
You can turn QuickCalc on from its button on the Palettes panel of the View tab, or with the keyboard shortcut Ctrl+8. Once it’s on, you can dock it to one side of the screen and/or set it to autohide for easy access later.
Across the top of the QuickCalc palette are several shortcut buttons for commonly used commands. “Clear” erases your current entry. “Clear History” erases your recent calculations from the large box below the toolbar. “Paste to Command Line” puts the current result in the command line, where you can use it as a value in an active command. The next four buttons return information based on points in the drawing. “Get Coordinates” and “Intersection of Two Lines” return a coordinate pair, the first from a single pick and the second from four picks that define two lines. “Distance” and “Angle of Line” return a single value—either the linear distance or the angle between two points. Finally, there’s a Help button, in case you forget what any of the other buttons do.
The two windows below the Toolbar are the History Area and the Input Box. Enter the values & operators for your calculations in the Input Box, and check your work or review previous entries in the History Area. You can even use the right-click menu to paste a previous value or expression into the Input Box.
Directly below the Input Box is the Number Pad. This looks a lot like any other calculator you own, with a few extra functions like “square root” and “pi” buttons. You can enter numbers into the Input Box either by clicking them in the Number Pad, or using regular keyboard entry.
For more complicated calculations, there’s the Scientific area. This contains several trigonometric and logarithmic functions, along with some extras like converting between radians and degrees.
My personal favorite is the Units Conversion area. Most projects in the US use feet-and-inches, but we’re starting to see more and more projects that are required to be documented in metric units. The Units Conversion area enables you to easily convert various length, area, volume, or angular measurements into a different unit without ever leaving AutoCAD LT. Once you’ve completed your conversion, clicking the calculator icon sends the converted value back to the Input Box, where you can use it in another calculation or send it to the command line for immediate use.
Finally, there’s the Variables area. This is the most powerful of the four entry areas, because you can create your own constants and functions and store them here for later use. The Variables area comes pre-loaded with several constant and function definitions, including Phi (the golden ratio) and dee (distance between two endpoints). Double-click a variable to paste it into the Input Box. If you double-click a function (identified by an “x”), press Enter to acquire the points or data needed to fill in the equation. Icons along the top of the Variables area enable you to create a new variable, or edit or delete existing variables. The calculator icon, as in the Units Conversion area, returns the selection to the Input Box.
Any these palettes can be collapsed to make it easier to see the ones you’re really using.