How Big Are Bed bugs?

Bed bug

Have you ever wondered, “how big are bed bugs?” You’ve probably heard they’re challenging to spot, which is why learning how to recognize other signs, like blood marks (from you!) and feces, can make a difference in how quickly you are able to attack the bed bug infestation in your home.

How big are bed bugs?

They’re tiny. So tiny, in fact, they are most often measured in millimeters instead of inches. Bed bugs molt several times throughout their life, starting at the egg stage, then nymph stage and working (growing) their way up to adulthood. When it comes to a bed bug problem, the sooner you identify your culprit, the better. Bed bugs are often mistaken for other pests, but fortunately, there are many identifying factors to help you figure out if you have bed bugs in your home. One of the biggest considerations is the size and how difficult they can be to actually spot with the naked eye. Do you know how big they are? Let’s discuss what to expect and other things you might see.


Bedbug eggs are an astonishing 0.09 inches, which is 2.5 millimeters. Good luck seeing them with a naked eye! And if you want to get rid of a bedbug infestation, these tiny, tiny eggs are what you need to attack.

Bed Bug size chart showing the growth of a bed bug from egg, to nymph and then as an adult.

Bed Bugs Appearance and Life Cycle | US EPA


It’s challenging to give an exact size for nymphs because they are anywhere between the egg size and adult size since they molt multiple times. However, according to the EPA, nymphs can range from 1.5 mm in its 1st stage life cycle to 4.5 mm in its 5th stage life cycle.

Adult bed bugs

Adult bed bugs are twice as big as the eggs, making it up to 0.18 inches, or 4.5 millimeters. If you’re trying to wrap your head around that size, consider that 0.1 inch is just a little thicker than a quarter. Basically, they are the size of an apple seed.

What Are Other Identifying Factors for Bed Bugs?

We mentioned that Bed Bugs are often mistaken for other pests so let’s walk through two additional ways you can identify bed bugs outside of just their overall size. 

  • Color: It depends on the stage in their lifecycle. Until adults feed, they are a mahogany to rusty brown color. Once engorged with blood, they become red-brown. Nymphs (baby bed bugs) are nearly colorless when they first hatch and become brownish as they mature.
  • Shape: Bed bugs have oval bodies and six legs.
Enlarged photo of a Bed Bug showing its oval shape and dark red-brown color.

Note the shape and color of an Adult Bed Bug.

Signs of A Bed Bug Infestation

Since these tiny pests stay hidden until it’s time for them to dine, it’s probably easier to spot the signs bed bugs leave behind. Once you discover bites on your arms, neck, or head, the next place to check is your mattress and sheets. Look for rusty stains from the crushed bugs and tiny clusters of brown or black spots on the mattress, especially along the seams. This is their excrement—a sure sign that you have a problem.

Bed Bug Treatment with Green Pest Solutions

Bed bugs might be small, but they are certainly a big issue that needs to be taken care of. Your local pest pros at Green Pest Solutions know this, and that’s why we provide meticulous bed bug removal services. Call us today at 877-636-9469 to get these invasive pests out of your home for good.

Bed Bugs Facts and Checklist

Bed Bugs Facts and Checklist

Remember how to identify common bed bugs that might have invaded your home and how to get rid of them.