How to Draw a Line & Give It a Length in AutoCAD

By Darrin Koltow

AutoCAD's polar coordinates allow specification of a line's length.
i Hemera Technologies/ Images

The 3-D design program AutoCAD gives you several options for drawing lines. One option involves moving the mouse to specify a line's length and slope. Another way is to type numbers indicating the exact length and slope of a line. The less precise mouse-based method is suited for sketching out designs, when precision isn't as important as getting some ideas down in graphical form. The more precise keyboard-based method of line specification is essential for the later stages of a design when manufacturing crews begin using the design.


Type "Line," then press "Enter." AutoCAD prompts you to enter the first point of the line.

Click the screen to specify the first point. Alternatively, type two numbers separated by a comma. For example, type "20, 30." These numbers are the x and y coordinates of the point, which tell AutoCAD where to locate the point horizontally and vertically on your display. After entering the first point, AutoCAD prompts you for the second point.

Type any number to indicate the length of the line you want to draw.

Press "<," which tells AutoCAD that the next number you enter will an angle, as opposed to a length or other dimension.

Press "Enter" to complete the specification for the line. AutoCAD draws the line between the points you specified, then prompts you to enter another line whose first point is the same as the last line's endpoint.

Press "Enter" to end the line creation mode.

Mouse and Menu

Click the "Line" command of the "Draw" menu. This places AutoCAD in line drawing mode.

Click any point on the canvas to specify the first point of the line.

Drag the mouse. AutoCAD displays two numbers and updates them automatically as you drag the mouse. One number is at the midpoint of a line parallel to the line you're drawing. This number indicates the changing length of the line. The other number is at the midpoint of an arc connecting your line's starting and current point. This number displays the angle of the line.

Drag the mouse until the length number described in the previous step reaches the length you want for the line. For example, if you want to make the line 10 units long and it's currently only 7 units long, drag the mouse further from the line's start point until the length number displays "10." Alternatively, type "10" into the small text box that displays the length number, then press "Enter." AutoCAD extends the line to the length you specified, while maintaining the angle number.

Press "Enter" to complete the line.