Are Bed Bugs Flat or Round? Resolved (Updated)

Last Updated on February 21, 2024 by Alene Schill

We can universally acknowledge that bedbugs are unpleasant and troublesome insects, and our immediate instinct is to eradicate them upon encountering them. Nevertheless, before resorting to using insecticide, it is important to be able to identify what they actually look like.

So, are bed bugs flat or round? It’s time to answer the question. 

Bed Bug Shape: Flat or Round?

round bed bug

There’s a lot of debate over whether bed bugs are flat or round, and the answer is both. Bed bugs can be either flat or round, depending on their stage in the life cycle.

As nymphs or young bed bugs, they are actually round. 

However, as they mature and grow older, they become more flattened. 

This is because it helps them to better hide in cracks and crevices where they like to reside. It also helps them to absorb heat from their environment better, which they need to survive.


Bed bugs are small, flat insects that feed on the blood of humans and animals. They are brown in color, and their bodies are oval-shaped. Bed bugs are typically 3/16 of an inch long, although they can swell to twice their size after a blood meal. [1]

Bed bugs have six legs and two antennae. They do not have wings, so they cannot fly, but they can move quickly over floors, walls, and ceilings. But are bed bugs squishy or crunchy?


Before Feeding

An unfed bed bug looks like a flat disc, and it is approximately 3/16” long. It is oval and about the size of an apple seed. 

On the other hand, an unfed nymph bed bug has a pale or yellowish color and is way smaller than an adult bed bug. So are bed bugs also long and skinny?

After Feeding

Once it has taken its blood meal, the bed bug becomes round, and its body blows like a balloon. The bed bug elongates; thus, it looks more like a torpedo than a disc. It also changes its color after feeding. For instance, the nymphs turn bright red and look like plump raspberries.



Bed bug nymphs are flat and oval-shaped, much like the adults, but they are smaller and lack the brownish-red color of the adults. The nymphs are also small and hard to see unless they are moving or have just fed recently.


group of bed bugs

At this point, they will mate and lay eggs to start the cycle anew. Adult bed bugs are about the size of an apple seed or about 4 to 5 millimeters long. They are flat, oval-shaped insects with six legs. 

Bed bugs can be brown, red, or black in color. They are also attracted to warmth and carbon dioxide, which is why they often gather near people and animals.


Are bed bugs flat looking?

Yes, bed bugs are flat-looking, small, and wingless insects that are reddish-brown in color and approximately the size and shape of a small apple seed.

They are flat looking before taking their blood meal or feeding, and they hide during the day and come out at night. But what do dead bed bugs really look like?

How do you tell if a bug is a bed bug?

You can tell that a bug is a bed bug if you wake up with itchy bites. Another indicator is when you find small, flat-looking, and wingless insects under your mattress that is about the size of an apple seed. [2]

Final Thoughts 

Bed bugs are both flat and round. Their sizes and shape may vary depending on what stage of the lifecycle they are in, but a few indicators can help you distinguish them from the common bug.

For instance, bed bugs are flat when they have not taken their blood meal yet and become plump or round after feeding. 

We hope the guide above can help you determine whether you are dealing with a bed bug problem so you can address the issue immediately.



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