Many factors, such as the space between extension lines and the arrowhead size, influence how dimension text and arrowheads fit within the extension lines. In general, AutoCAD LT automatically applies the best fit, given the available space. If possible, both text and arrowheads are accommodated between the extension lines, no matter what fit option you choose.
When creating new dimensions, you can place text by entering coordinates or using the pointing device; this is known as user-defined text placement. Alternatively, AutoCAD LT can compute the text position for you. The options for automatic fitting of text and arrowheads are listed under Fit in the Format dialog box. For example, you can specify that text and arrowheads be kept together. In this case, if there is not room for both between the extension lines, they are both placed outside. You can specify that if there is room for only text or arrowheads, then either text only or arrowheads only are placed between the extension lines.
If there is no room for text between the extension lines, you can have a leader line created automatically. This is useful in cases where text outside the extension lines would interfere with other geometry, for example, in continued dimensions. Whether text is drawn to the right or the left of the leader is controlled by the horizontal justification setting (see Positioning Dimension Text Horizontally). Also, you can fit text and arrowheads by changing their size.