What size are bed bugs? – with images to compare

Dave Campbell

Bed bugs are a real nuisance if you have them in your home, but one of the things many people are unsure of is what these insects look like, their shape, their appearance, their eggs and to know what size these pests grow to. Before calling a pest control expert, find out if you really are dealing with an infestation in your home or room and not something else that looks like these bugs, such as other types of beetle. And of course if you have never seen one before you may wonder about ways to identify them and how they can be visually compared to other pests that you know well. Of course if your want to know how to get rid of bed bugs, it’s important to know what you are looking for.

What do bedbugs appear like to the human eye?

The first things to look out for is bug bite marks on the skin and other possible symptoms before assuming a bug invasion. A correct identification is necessary for the proper treatment needed, if any. If you or one of your children have bites like the picture below, and they are sore and itchy, it could well be the result of bedbugs. It’s always best to check with a doctor just to make sure it isn’t some other condition. See the pictures and photos of below to get an idea of signs to watch for. Check out my other post about bed bug nymphs and what to look out for(with pictures). 

bug bites

Image of bites

These bugs will tend to show up as dark brown color, and  so are quite easy to spot against a whole bed sheet or duvet.

If you do suspect an infestation, you will need to turn over all your bedding, duvet covers, pillow cases and all around the mattress. This photo shows ways that they appear on bed covers.

pictures of bed bugs on mattress


Pictures of bugs on mattress

What length and width are they?

Well it depends. Bed bugs grow significantly though their life cycle and can start off quite small from the nymph stage before becoming adult bugs, which are between 5 and 7mm long, about the dimensions of an apple seed. After feeding on human blood, they can also swell to about twice normal size during their life. Adults have flat oval shaped bodies compared to the babies. Also they lay eggs which are a bit harder to see and much smaller, sometimes found on the skin.

Bed Bug pictures actual size

bug on a pencil

The images below will give you a sense of scale of an adult bed bug next to a person’s fingernail.

bug on a finger

Nymphs can appear the one in the picture below.

bug nymph
Bed bug nymph -commons.wikimeida.org

So can I know if I have an infestation?

If you look carefully, you will be able to find signs of bugs around your house. If they have fed recently, will appear as a brown or reddish color, as they feed on human blood and have quite a flat shape.  You might also find their eggs, which are a white color and are smaller than a grain of rice. The nymphs are harder to see as they have transparent bodies, but can appear white.

Treatment options

If you do find any, you will need to treat the pest problem thoroughly to remove of all the bedbug eggs, nymphs and adults, to prevent them returning, even though they don’t present a serious health risk. For a light infestation, you may get away with just washing all the bed coverings. However, for a bad pests infestation, you might need to throw all your bedding in the bin and replace your mattress too. If it is a devan bed, these insects can also live inside the bed, so best to replace everything if necessary. It is also well worth checking all your clothing as a bedbug can transport itself on clothes too. Also, it may be worth while calling in a professional pest control company who have experience with infestations. 


Can you see bedbugs with the naked eye?

If you know what to look for, such as some of the signs mentioned above, then you will be able to see bed bugs without having to use a magnifying glass. They vary in dimensions, but depends on where they are in a life cycle. Typically, nymphs will be smaller than a fully fed adult, but still visible. A bug that has eaten a blood meal, will be bigger than a regular one. On average though, they appear about the size of an apple seed. The adult insects have a flat body shape compared to the nymphs, especially after they feed.

Are bed bug eggs hard?

No, they are in fact quite soft and you can squeeze them with your fingers. An egg is about 0.5mm in length, however, they may be difficult to pick up as they have a sticky substance that makes the eggs stick to surfaces.

What do they look like on a mattress?

Bed bugs found on a bed mattress will tend to appear dark in color against the backdrop of a light colored mattress and other objects around your home. They may appear like little black seeds, as shown in the photograph above, with the adult bugs a bit larger.


Dave Campbell

I'm Dave Campbell and the owner of deadpestz.com. You can read more about me and my background on my About Me page.

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