Carpet Beetle vs Bed Bug: What are the Differences?

Big black beetle - Carpet beetle
© Tomasz Klejdysz/

Written by Emmanuel Kingsley

Updated: July 2, 2022

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Both carpet beetle and bed bug have one thing in common; nobody wants them near their homes. Both insects are known for their devastating effect on furniture, clothes, and human blood. They both produce the same effect and you might be unable to tell them apart at first glance. However, there are distinctive features that set the two apart. We’ll look into their differences in this post.

Comparing a Carpet Beetle and a Bed Bug

A carpet beetle is smaller than a bed bug.
Carpet BeetleBed Bug
Size0.125 to 0.188 inches long.0.197 to 0.276 inches long
AppearanceFlat oval shape with a black, white, yellow, and brown scale giving a spotted or striped appearanceFlat oval shape with a brownish-red color.
Behaviour Feeds during the day and undergoes complete metamorphosis.
Does not bite, but larvae produce allergic reactions
Nocturnal insects.
Produce bite marks from feeding.
DietFeeds on fibers, wool, leather, and plant-based materialsFeeds on blood

The Key Differences Between a Carpet Beetle and a Bed Bug

The key difference between a carpet beetle and a bed bug is in their mouths. While a carpet beetle’s mouth is designed to chew on plants and fibers, the mouth of a bed bug is able to pierce human and animal flesh so it can feed on blood.  Other differences between carpet beetles and bed bugs are in their size, appearance, and behavior. Although both insects have the same oval shape, the bed bug’s form is sharper than the carpet beetle’s. 

And while the carpet beetle is a nocturnal insect, the bed bug prefers to stay hidden and is only active at night. But these are not the only differences between the two insects. Let’s explore their differences in detail!

Carpet Beetle vs Bed Bug: Size

At first glance, carpet beetles and bed bugs may look similar, but upon a closer inspection, you will notice they are slightly different in size. When it comes to size, the bed bug tends to grow larger, averaging a size of about 0.197 to 0.276 inches long. On the other hand, the carpet beetle only grows to about 0.125 to 0.188 inches in length.

Carpet Beetle vs Bed Bug: Appearance

Types of Bed Bugs

Bed bugs flat and oval-shaped body gives them the appearance of an apple seed.

©Pavel Krasensky/

Generally, the carpet beetle is oval and usually appears to be black or brown, depending on the species. Also, they come with some unique color like yellow and white, which is usually dotted across the thorax, giving a stripped or dotted look. These unique color scales give the carpet beetles distinct appearances, although they tend to fade into black or brown color as the insect ages. The color scale is not just useful in differentiating the carpet beetle from a bed bug, it is also vital in species identification. For example, the furniture carpet beetle has a white, yellow, or orange body, while the varied carpet beetle has a white and yellow pattern.

On the other hand, bed bugs are distinct with their brownish-red color and semi-translucent body. Generally, their flat, oval-shaped body gives them the appearance of an apple seed. While they share this oval-shaped feature with the carpet beetle, it is more pronounced in the bed bug.

Carpet Beetle vs Bed Bug: Behavior 

Carpet Beetle Larvae - Adult Carpet Beetle

The carpet beetle’s larva has hairs on their body that causes irritation evidenced as rash marks as they crawl on human bodies.

©Tomasz Klejdysz/

Another major difference between the carpet beetle and the bed bug lies in their typical behavior. While the carpet beetle is diurnal (meaning they are active during the day), bed bugs are nocturnal (they only come out at night to feed while mostly hiding during the day).

Besides, carpet beetle can be found about just anywhere you have fibers that they can consume, but you will find a bed bug in dark places, usually along the tip of a bed and other crevices that shields them from light. 

It is assumed that both insects bite, but this is not true for a carpet beetle. Although they may produce a bite pattern or what looks like it, the carpet beetle does not bite because its mouthparts are not designed for it. Their diet mainly consists of wool, fiber, furniture, and other pieces of clothing, which may lead them to crawl on humans in search of their food.

What is presumed to be a bite mark is actually an allergic reaction produced when their larva comes in contact with the human skin. Carpet beetle’s larva has hairs on their body that causes irritation evidenced as rash marks (which closely resemble a bite) as they crawl on human bodies.

Blood is vital to the life cycle of a bed bug since they require it for many biological processes. Since they are nocturnal insects, they search for their food at night and will travel a fair distance to get it. Bed bugs bite since they need to access their food (blood). Usually, they produce bite marks which are usually seen in a row of three as they feed in groups.

Carpet Beetle Vs. Bed Bug: Reproduction

Another telling difference is their reproductive behavior. While carpet beetles undergo complete metamorphosis, their counterpart does not. The carpet beetle metamorphosis process is egg, larva, pupa, and adult. It goes through a larva stage that differs from the adult in appearance. The adult version is significantly smaller compared to the larva stage. On the other hand, bed bugs’ metamorphosis process is egg, nymph, and adult. The nymph looks like the smaller, translucent version of the adult.

Carpet Beetle vs Bed Bug: Diet 

Carpet beetles and bed bugs have no similarities in their diet. The carpet beetle is considered a danger to possessions since they wreak havoc on clothes, curtains, furniture, and anything that remotely contains fiber, wool, leather, and felts. 

Some carpet beetle species are known to infest plants, seeds, and other plant-based materials. Due to their diverse diet, they can be found practically anywhere in the home. 

Unlike the carpet beetle, bed bugs thrive on blood, often depending on the shiny red liquid for many biological activities like reproduction. The availability of blood can quickly expand a small colony with an adult female capable of laying five eggs per day.

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