AutoCAD Tip – Using AutoCAD’s built in Calculator

By Dennis Collin

Even though visiting customers offices is rare with the current remote working environment I still see users’ workstations with a desk calculator and being used to work out values on drawings without using AutoCAD’s own calculator functions. Furthermore, many users don’t realise that AutoCAD can perform command line calculations even without typing the apostrophe or “calc” or the Quick Calculator.

Functions or expressions can be input directly on the command prompt.

The format is…

(Expression value value)

For Example, typing in (+ 2 2) <ENTER> on the command prompt returns the value of 4.

This method works in a similar way to how formulas are used in Excel.

For example… (+ (* 2 2) 1) yields a value of 5. Also, the expression (* (+ 2 2) 2) yields 8, because the inner parentheses are evaluated first.

Expressions can also be used on AutoCAD commands like Move and Scale in the example below a user wanted to work out a scale by arithmetic means, then the “ ‘cal ” option can be entered on the command prompt with appropriate operators used to calculate a desired result.

The resulting operation will then scale up an element by a factor of 4. ‘cal enables AutoCAD’s calculator function to operate transparently in a command.

In addition to using numerical values AutoCAD’s calculator can also utilise object snaps to work out positions or to locate elements to draw.

In the example above, a point needs to be created at the centroid location between 3 object snaps. In this case 3 rectangles of various sizes and rotations. A corner snap for a rectangle could include an Endpoint reference or an intersection.

Command Syntax is as follows:

Point <ENTER>

‘cal <ENTER.

(end+end+end)/3 <ENTER>         OR          (int+int+int)/3 OR         any suitable mix of Osnap overrides

Once completed the point is placed as per the image below.

Want a more modern interface? The same level of functionality can be employed with AutoCAD’s Quick Calculator and dialogue interface. This feature has been in AutoCAD for over 20 years but is frequently missed or forgotten about by even experienced AutoCAD users.