Arrowheads and Leaders In Technical Drawings

There are different standardizations of technical drawing such as ANSI and ISO. If you create your technical drawing according to these standards, your template will be international. 

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Even the most basic aspects of technical drawings such as arrowheads and leaders must comply with the standards. Here you can find satisfactory information about the arrowhead and leader standards in technical drawings. 


In technical drawings, arrowheads must have the same appearances all around the sheet for clarity. There are various sizing standards of arrowheads. But most used standards of arrowheads are; 

  • They must have a 3:1 length and width ratio. 
  • They must have the height of the same value of dimension numbers and values on technical drawings. 

Arrowheads must be filled with a solid color for the best appearance. 


Leaders are commonly used in technical drawings to show the required details. Leaders are solid thin lines drawn on technical drawings. The most important rule of the leaders in technical drawings is that; If you are indicating a line on the part on the technical drawing, start the leader with an arrowhead. But if you are showing an internal side of a technical drawing part, start the leader with a dot to show that. 

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To obtain the best appearance, make the multiple leaders parallel each other and align. 

Across the leader, lines are not desired in technical drawings. And do not make the leader lines parallel to the part’s entities and lines on technical drawings. Do not make the leader line too long. Horizontal or vertical leader lines are not desired. 


If you are using a CAD program to obtain technical drawings such as Autocad, you can adjust the options of the leaders and arrowheads according to these standards. 

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