How To Divide Lines: The Holy Grail for Great Drawing

Proportion and Dividing Lines

Dividing a Line Equally without a Ruler

Anyone who has picked up a pencil and wanted to make an accurate drawing knows the most important thing is proportions. That means you need to divide things up. Sometimes into several pieces. Now you can eyeball it but if you want to get to a better level of accuracy then you want to use a few simple techniques that will take your drawing to the next level. 

Dividing a Line Segment into 5 Equal Parts

Now I can use this method to divide the line into any number of parts but for this exercise, I will divide it into five equal parts.

1. First, draw the line you need to divide. I  used a straight edge. Of course, this could be freehand and I use this method freehand all the time. The “A” and “B” are just to show where the line starts and stops.

2. Next, I will use a second line to divide my first line. This second line has to intersect where the first line begins at point “A”. This second line I will use to divide my first line can be any “length” and any “angle”, it doesn’t matter.  I drew an arbitrary line of an arbitrary angle from point “A”. As pictured below

3. Next, I will divide the second line into equal incremental lengths. THE SIZE OF THE INCREMENT’S LENGTH DOESN’T MATTER. WHATEVER THE INCREMENT SIZE IS, IT JUST HAS TO BE REPEATED EQUALLY FIVE TIMES. I used a compass to divide the line into five equal lengths. I could have used a ruler or the length of the sharpened end of my pencil or just two random marks on a piece of paper that I repeated five times to make 5 equal distances of any length.  Below shows 5 marks of equal length on the second line we will use to divide line AB.

4. YOU MUST CONNECT THE POINT OF YOUR 5TH INCREMENT TO POINT “B” CREATING A TRIANGLE. From your last mark connect it to POINT B. We have made a triangle.


5. Mark the points on line AB and erase your work lines. Now you have a line that is divided equally into 5 parts. Again I use this will hand sketching all the time.

Now the great part is you can do this by hand the same process and you will divide things much more accurately and quickly than you ever thought possible. Give it a try.

Video Showing ” How to Divide a Line”

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11 thoughts on “How To Divide Lines: The Holy Grail for Great Drawing”

      1. I don’t understand either. also I don’t understand where you have the answer to Chris who also doesn’t understand

        1. Hello Sandy,
          I tried to go back once again to edit the post to see if it clarifies the process. I am thinking I will make a video showing the process by hand to see if that makes it more clear. I think it would. I appreciate your comment.

          1. Please make a video about this. Why is it so important to have a line divided into 5 parts in drawing anyways? What does this have to do with proportion?

          2. Hello Hannah, This technique can be used to divide a line into any number of equal lengths. I used five because we use it all the time for portraiture since the head is measured in five eyes spaces. This not only works 2 dimensionally or in flat space but also in perspective and can be very handy in drawing cityscapes and houses, cars and all manner of stuff.

  1. So…..
    You divided a line easily with a compass. Why not just do that? Both lines look identicle, so why bother? Devil’s advocate, here;-)
    Great website, thanks!!

    1. I would not use a compass because I don’t like holes in my paper. Plus I don’t want to always have to lug around a compass when sketching, I can use this with sketching very easily and continue to develop the drawing.

  2. The point is to divide a line of specified length without needing to do calculations. I really like the added ease of not even needing a ruler, per se, just something as simple as two lines on paper, or the end of a pencil. An elegant solution. Thank you!

  3. Why dont you show us its application? Under your 5″ line demo was a portrait you had drawn (I presume,) And how is the 5″ line used in larger drawings. Or are you showing how to divide any line into 5 parts. I never heard of this.5 part measuring system so perhaps you can.mention the use of this method in portraits….

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