How Big Is 3.5 Inches: 17 Real-World Examples

Human brains can learn the perception of lengths through visual references. For example, visualizing an object of a known length helps us assume the unknown length of another object. When things are small, such as 3.5 inches, a lot of reference objects are there.

So, how big is 3.5 inches? It is as big as a soap bar, pocket mirror, paperweight, pocket knife, hard disk drive, staple remover, or business card. A lot of other objects in our daily lives also have the same length. 

Let’s delve into the dimensional discussion of 17 common objects that measure about 3.5 inches.

17 Objects That Are 3.5 Inches Long

So, to answer the question of how big is 3.5 inches, 17 objects I will compare below. And don’t mind if I mention any brand name to make the objects more familiar. Let’s begin.

1. The Middle Finger

It may sound inappropriate, but the middle finger is the best built-in scale in humans to measure 3.5 inches. The average length of the middle finger of an adult male is about 9 cm or 3.54 inches. You can easily measure an object by comparing its length to that of the middle finger.

Remember, the actual length of the middle finger can vary from person to person. For example, females have a slightly shorter middle finger.

2. A Sticky Note

Sticky notes are square pieces of paper that have a dimension of 3 x 3 inches. This is the standard dimension. You can use a sticky note to have a rough idea of how big 3.5 inches is. Some sticky notes are also available in 3.5 x 3.5 inches.

3. Five US Dimes or Three Half-Dollar Coins

According to the US Mint, the diameter of dimes is 0.705 inches or 17.91 mm. If we round the diameter, we get 18 mm or 1.8 cm. So, if you place five dimes side-by-side so that they touch each other, the total length will be 90 mm or 9 cm. It equals 3.54 inches, which is pretty close to our desired length.

Another way to measure 3.5 inches with US coins is to use the half-dollar coin. The diameter of the half-dollar coin is 1.2 inches or 30.61 mm. If you place three half-dollar coins together, the length from one end to the other will be just over 9 cm. So, it can be a good reference point.

4. A USB Drive

USB drives are a must in this digital age and most of us carry at least one in our pockets. These small storage devices are about 3.5 inches long. The length can be slightly more or less. 

Most USB drives having a long, rectangular shape will fit in this size range. 

5. A Nail File

The most common nail files are about 3.5 inches. Regardless of the material, most nail files usually have this length so that they easily fit in pockets or purses. As this is no standard size, I recommend using more specific references for 3.5-inch measurements.

6. A Pocket Knife 

Pocket knives are much smaller than regular knives because their blades and handles are smaller. The most common pocket knives have a blade length of about 3.5 inches. With the length of the handle, the knife may be a bit longer. 

You should remember this length more than other references. This is because carrying knives with a blade length of over 3.5 or 4 inches may be illegal.

7. A Coaster

Coasters are commonly found in two shapes: square and circular. Also, there are two variations in size. Small square coasters have a side length of 3.5 inches, while circular coasters have a diameter of 3.5 inches.

You can use a coaster as a very good reference object to measure 3.5 inches. Don’t use the large ones because they have a side or diameter of about 4 inches.

8. Three Soda Bottle Caps

The exterior diameter of a soda bottle cap is about 3 cm or 1.18 inches. Three soda bottle caps will measure about 3.54 inches or 9 cm together. Remember, the size of the soda bottle caps is often the same, regardless of the volume of the bottle.

So, you can use the cap of any bottle to measure this length.

9. A Ceramic or Paper Cup

Regular cups we use to drink coffee or tea have a diameter of 3.5 inches. Remember, this is the diameter of the widest part or the opening of the cup. At the bottom, the diameter of the cup can be smaller depending on its shape.

Paper cups used in restaurants often have the same diameter. The paper cups that can contain about 12-20 fl. oz. of liquid are 3.5 inches in diameter. If you have a cup that can contain 8 oz. of liquid, its diameter will be about 3 inches. 

But its height will be 3.5 inches. So, you can use the diameter or height of these cups as an exact reference.

10. A Hard Disk Drive

Older hard disk drives are about 3.5 inches in width. This is why they are often called 3.5-inch drives. Remember, I am talking about the large hard disk drives with rotating mechanisms inside. Modern solid-state drives are much more compact than old hard disk drives.

11. A Pocket Mirror

Women commonly use these mirrors for cosmetic touchups on the go. The size of these mirrors is about 3.5 inches, so that they easily fit into purses. These mirrors are generally found in two shapes. The square ones have a side length of about 3.5 inches.

For circular mirrors, you have to use the diameter as a length reference.

12. A Staple Remover

Staplers and staple removers are common office stationeries. While staplers are a bit larger, staple removers perfectly fit into our size criteria. A standard staple remover is about 3.5 inches long. There can be some size variations depending on the size of staples it removes.

I am talking about staple removers that are used for common staple sizes, such as 26/6 or 24/6.

13. A Business Card

This is one of the most common 3.5-inch objects in our daily life. A standard business card has dimensions of 3.5 x 2 inches. So, the length of a rectangular card will be 3.5 inches. 

Remember, the size of a business card can vary depending on its design and material. For example, metal or plastic business cards may be a bit larger.

14. A Toilet Paper

The standard toilet paper rolls we use have a width of about 3.7 inches. Even though it is a bit larger than our desired length, you will have a rough idea of the length. Some toilet papers can have a bigger width.

15. A Medium Toothpick

Toothpicks usually come in three sizes. Small ones are about 2.35 inches, medium ones are about 3.5 inches, and large toothpicks are about 4 inches long. 

You can use a medium toothpick to measure something if the length of that object is 3.5 inches or if it’s multiple.

16. A Soap Bar

The standard size of soap bars is about 100 mm or 3.9 inches. I am talking about the most common size used in households. Hotels may have smaller soap bars for individual guests. And some beauty soaps come in larger sizes as well.

17. A Paperweight

Paperweights come in various designs and shapes. The most common shapes are square or circular. The side length of a square paperweight is about 3.5 inches. Circular paperweights are slightly smaller, but you can use them as a reference.

Conclusion

Length reference of common objects is very useful in busy lives where we need to measure the length of other objects without a measuring tape. For rough estimations of 3.5 inches, we can use a lot of common objects. So, how big is 3.5 inches?

I compiled 17 common objects in our day-to-day lives that have a length, width, or diameter of 3.5 inches. Some objects have slight length variations, but that is negligible. If you need more accurate measurements, you must use a ruler or measuring tape.