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When a straight line passes from side to side through the center of a circle or a sphere, we call it the *diameter* of the object. So, **what is the diameter of a pencil?** In simple terms, the measurement from one side of the pencil to another side through the center is called the diameter of a pencil.

**If you measure the diameter of a standard, hexagonal no. 2 pencil, the hexagonal diameter will be about 6 millimeters (¼ inches). The outer diameter of the pencil will be approximately 7 millimeters (****9****⁄****32**** inches).**

This is a rough measurement of the diameter. In this guide, we will talk more about pencil diameter, how you can calculate the diameter of a pencil on your own, and so on. Let’s dig in.

Table of Contents

**What is the Diameter of a Pencil?**

To understand the diameter of a pencil, you need to chop it off the top first. The most common type of pencil is a hexagonal one, so if you chop it off and look at it from the top, you’ll see a hexagon. You might not be able to understand the diameter from this, but if the pencil is round, you will notice a perfect circle.

Now, this circle’s diameter can be defined the same way a mathematician would define any regular circle. So, what is the diameter of a circle? If math freaks you out, no worries, I’ll try to keep it as simple as I can.

In a circle, the diameter is a straight line that goes through the center and whose ends rest on the circumference of the circle. In simpler words, if you start a straight line from one side of the circumference, take it through the center, and finish it on the other side of the circumference, you will get the diameter.

All the lines drawn in the same manner will be of the same length, regardless of the direction. The diameter is the longest line you can draw inside a circle. If these terms make sense to you, you can now go ahead and measure the diameter of your pencil.

To measure stuff like this, you can opt for Vernier Calipers or a Screw Gauge. You will need to set the pencil inside the external jaws of the Vernier Calipers, fit it well, and you will get the diameter. However, you don’t need to go through all these hassles.

**We are here with the answer. Since pencils are mostly hexagonal, if you measure the diameter of a standard, no. 2 pencil, the hexagonal diameter will be about 6 millimeters (¼ inches). The outer diameter of the pencil will be approximately 7 millimeters (****9****⁄****32**** inches).**

Also Read: **Weight Measurement of a Pencil**

**What is the Thickness of a Pencil?**

If we ignore the entire math behind measuring the diameter of the pencil, we can simply consider any straight line that goes through the center and whose ends rest on the circumference is the thickness of a pencil.

You can feel the thickness of a pencil as soon as you place it between your thumb and index finger; no need to use complex mathematical measuring tools.

**What is the Diameter of a Pencil in CM?**

Once you get the result of measuring the pencil in millimeters or inches, you can easily convert it to centimeters. Now, this section is loaded with some math stuff, but hopefully, you’ll understand.

**The formula for Converting mm to cm**

1 millimeter (mm) is equal to 0.1 centimeter (cm).

So, the formula for converting to centimeters would be:

**cm = mm/10**

So, if we take a standard no. 2 pencil, the hexagonal diameter in centimeters would be roughly 6/10 = 0.6 centimeters and the outer diameter of the pencil would be roughly 7/10 = 0.7 centimeters.

**Formula for Converting inches to cm**

Since 1 inch is equal to 2.54 cm, you need to multiply the inches value by 2.54.

So, the formula for converting to centimeters would be:

**cm = inches X 2.54**

If you get the results in inches after measuring a pencil, you can convert the diameter of it into centimeters, by applying this rule.

**What is the Diameter of a Pencil in MM?**

If you get the results in millimeters after measuring the pencil, your job is easy as pie. But if you get it in centimeters or inches, you need to apply some formulas similar to what we said earlier.

**Formula for Converting cm to mm**

1 centimeter (cm) is equal to 10 millimeters (mm). You need to multiply the centimeter value with 10 to get the millimeter value. So, the formula for converting to millimeter would be:

**mm = cm X 10**

**Formula for Converting inches to mm**

Since 1 inch is equal to 25.4 mm, you need to multiply the inches value by 25.4.

So, the formula for converting to a millimeter would be:

**mm = inches x 25.4**

Continue Reading: **The materials of Wooden Pencil**

**What is the Diameter of a Pencil in Inches?**

The hexagonal diameter of a standard no.2 pencil is roughly ¼ inches or 0.24 inches. And the outer diameter of the pencil is approximately 9⁄32 inches or 0.28 inches. You can also apply formulas to calculate the diameter.

For converting a centimeter value to inches, you need to divide the value by 2.54. And if you want to convert a millimeter value to inches, you need to divide the value by 25.4.

**What is the Diameter of a Colored Pencil?**

This may vary from brand to brand. For example, the diameter of a Faber-Castell Polychromos **color pencil** is 8 mm or 0.315 inches. Other brands may come up with pencils with a different diameter.

Since we are talking about colored pencils, we can’t ignore **crayons**, whose diameters are not the same as regular colored pencils. So, the diameter of colored pencils is not a one-size-fits-all measurement.

**What is the Diameter of a Pencil Eraser?**

Erasers do not come in a one-size-fits-all size as well! Some **pencil** **erasers** can be about 5 millimeters in diameter, some can be 6 millimeters, and so on. Nowadays, there are pencil top erasers that come in different shapes. The shapes are so unique; probably you wouldn’t be able to measure the diameter.

**Final Thoughts**

Pencil diameter can affect the comfort of your writing or drawing. If you are used to writing with a specific pencil, switching to a pencil with a different diameter can make you feel uncomfortable.

In this article, we talked about the diameter of a pencil. So, whenever you switch pencils and feel uncomfortable, you can measure the diameter yourself to see if there is anything wrong with the thickness.

Hi, I’m Andy Gary, the founder of Writers Need and a stationery enthusiast. I love to blog about anything regarding writing and have created lots of pages that I can now share with others!