Quick answer
An adult bed bug looks like a flat, oval, reddish brown insect about the size of an apple seed (5 to 7 mm, or about 1/4 inch long). It has 6 legs, 2 short antennae and no wings. After it feeds, it swells up, gets longer and turns a darker, deeper red. Young bed bugs (nymphs) are smaller and pale yellowish white, and eggs are tiny pearly white ovals about 1 mm long.
Found a small brown bug in your bed, on the couch or in a hotel room and wondering if it is a bed bug? This guide shows you exactly what bed bugs look like at every life stage, how big they really are, how they change after feeding, and how to tell them apart from the bugs people most often mistake them for.
Our licensed technicians inspect homes across California every day, and the number one question callers ask is “is this a bed bug?” The good news is that adult bed bugs are easy to recognize once you know the few features to look for.
Key takeaways
- Adult bed bugs are 5 to 7 mm long, about the size of an apple seed, and you can see them with the naked eye.
- Unfed adults are flat, oval and mahogany or reddish brown. Fed adults are plump, longer and darker red.
- They have 6 legs, 2 antennae, small wing pads but no working wings. They cannot fly or jump.
- Nymphs are 1.5 to 4.5 mm and pale or see-through until they feed, then they look bright red.
- Eggs are about 1 mm, pearly white and usually tucked into seams and cracks.
- Bat bugs, carpet beetles, cockroach nymphs and booklice are the most common look-alikes.
What Does a Bed Bug Look Like?
The common bed bug (Cimex lectularius) is a small, wingless insect that feeds only on blood, mostly human blood, while people sleep. Here are the features that identify an adult:
Unfed bed bugs are as flat as a credit card from the side, which lets them slip into mattress seams and cracks.
Adults are mahogany or rusty brown. After a blood meal they turn a deeper red to almost purple.
Adults are about 5 to 7 mm long (3/16 to 1/4 inch). Big enough to see, small enough to miss.
Six legs, two antennae and tiny wing pads that do not work. Bed bugs crawl. They do not fly or jump.
Look closely and you will also see a banded, striped look across the abdomen, fine golden hairs on the body and a short beak folded under the head. Bed bugs also give off a sweet, musty smell from their scent glands, which becomes noticeable in bigger infestations.
Bed Bug Anatomy: Labeled Diagram
This labeled illustration shows the parts a pest control inspector checks when identifying a bed bug. Zoom in on mobile to see the details.
How Big Is a Bed Bug? Actual Size Comparison
People often expect bed bugs to be either microscopic or much bigger than they are. Here is how each stage compares with an apple seed and a US penny. The bugs are enlarged so you can see them, and sizes are listed under each one.
So yes, you can see bed bugs with the naked eye. Adults and older nymphs are easy to spot on a light sheet. Eggs and the youngest nymphs are much harder because they are pale and about the size of a pinhead, so a flashlight and a magnifying glass help a lot.
What a Bed Bug Looks Like Before and After Feeding
A bed bug can look like two different insects depending on when it last ate. Use the switch below to see the change.
Flat as paper from the side, oval, light to medium reddish brown. This is how you usually find them hiding in seams during the day.
Swollen, longer and more cigar shaped, dark red to purplish. A freshly fed bug leaves a small blood smear if crushed.
A bed bug feeds for about 3 to 10 minutes and then crawls back to its hiding spot. Because they feed and hide so fast, most people find them during the day in their unfed, flat form, tucked into mattress seams.
Bed Bug Eggs, Nymphs and Adults
Bed bugs go through 3 life stages: egg, nymph and adult. Nymphs molt 5 times, and each molt needs a blood meal. In a warm home, the full cycle from egg to adult can take about 5 to 6 weeks.
About 1 mm, pearly white, shaped like a grain of rice. Laid in seams, cracks and rough surfaces, often in clusters. They hatch in about 1 to 2 weeks. Hatched shells look like tiny empty white cases.
Young bed bugs, 1.5 mm to about 4.5 mm. Pale, straw yellow or almost see-through, so a freshly fed nymph shows a bright red spot of blood inside. They look like smaller, lighter adults.
5 to 7 mm, reddish brown, flat and oval. A female can lay hundreds of eggs in her lifetime, and adults can survive for months between meals, longer in cool conditions.
Want a closer look at every sign bed bugs leave behind? Our guide on what bed bug bites look like covers bites, patterns and the rusty stains that point to an infestation.
Bed bug inspection and treatment in California
Found eggs, nymphs or adults? Get a licensed pro to confirm it.
Our licensed technicians come to you for a bed bug inspection and give you a written treatment quote. It costs nothing to call.
Bugs That Look Like Bed Bugs (and How to Tell Them Apart)
Many small brown bugs get mistaken for bed bugs. Pest control technicians see these look-alikes all the time. Here is how to tell them apart.
Almost identical to bed bugs. The difference is longer hairs on the collar behind the head, visible only under magnification. Common in homes with bats in the attic or walls. A pro should identify these.
Round, hard shelled and often spotted with white, brown and orange. Their fuzzy, striped larvae can irritate skin. They do not bite or feed on blood.
Longer and narrower, with very long antennae, and they run fast. Usually found in kitchens and bathrooms, not in bedding.
Tiny, dark and narrow from side to side, not flat from top to bottom. They jump. Bites cluster on ankles, and pets are usually involved.
Have 8 legs, not 6. Usually picked up outdoors and found attached to skin or pets, not hiding in mattress seams.
Very small (1 to 2 mm), soft and pale gray or tan. Found near damp spots, books and stored food. They do not bite.
| Bug | Shape | Color | Moves by | Bites people? |
|---|---|---|---|---|
| Bed bug | Flat, oval, apple seed size | Reddish brown | Crawling | Yes, at night |
| Bat bug | Same as bed bug | Reddish brown | Crawling | Rarely, if bats leave |
| Carpet beetle | Round, hard shell | Spotted or black | Crawling, flying | No |
| Cockroach nymph | Long, narrow, long antennae | Brown to dark | Running fast | No |
| Flea | Tiny, narrow side to side | Dark brown | Jumping | Yes, often ankles |
| Tick | Round, 8 legs | Brown to gray | Crawling | Yes, attaches |
Quick Check: Is It a Bed Bug?
Look at your bug (or a clear photo of it) and tick every statement that is true. The more boxes you check, the more likely you have found a bed bug.
Where to Look for Bed Bugs
Bed bugs hide close to where people sleep or sit for long periods. They like tight, dark cracks. Use a flashlight and a thin card to check these spots, starting with the bed.
- Mattress seams, piping, tags and corners
- Box spring, especially under the fabric cover
- Headboard, bed frame joints and screw holes
- Couch and recliner seams and cushions
- Nightstands, baseboards, outlet covers and picture frames
- Luggage and bags after travel
While you check, look for the other signs of bed bugs too: small dark or rusty spots (droppings and blood), pale shed skins, eggs and empty egg shells, and a musty odor. One live bug plus any of these signs is strong evidence.
What to Do If You Found a Bed Bug
- Catch it if you can. Press clear packing tape over it, or drop it in a zip bag or pill bottle. A sample makes identification easy.
- Take a sharp photo next to a coin or ruler for size. This helps our technicians confirm it quickly.
- Do not move to another room or the couch. Bed bugs follow people and you can spread them through the home.
- Do not use foggers or bug bombs. They rarely reach bed bugs in cracks and can push them deeper into walls and nearby rooms.
- Bag and heat your bedding. Wash sheets and clothes, then dry on high heat for at least 30 minutes.
- Get a professional inspection. A licensed inspector, or a trained K9 team, can confirm the bug and find out how far the infestation has spread.
If you rent in California, tell your landlord or property manager in writing. State law (California Civil Code sections 1954.600 to 1954.605) requires landlords to give tenants bed bug information and share inspection results, and it protects tenants from retaliation for reporting.
Good to know: the CDC notes that bed bugs are not known to spread disease. Finding one does not mean your home is dirty either. Bed bugs travel in luggage, used furniture and backpacks, and they turn up in clean homes, apartments and hotels all over California.
How Our Licensed Technicians Treat Confirmed Bed Bugs
Once our licensed technicians confirm bed bugs, we recommend one method or a mix, based on how big the problem is and the type of building.
K9 inspectionTrained dogs sniff out live bugs and eggs, useful for apartments, hotels and early infestations.
Heat treatmentRooms are heated to about 120°F or more to kill all life stages, often in 1 day.
Chemical treatmentTargeted products applied to cracks and seams, usually 2 to 3 visits about 2 weeks apart.
Frequently Asked Questions
What does a bed bug look like to the human eye?
To the naked eye, an adult bed bug looks like a small, flat, oval, reddish brown bug about the size of an apple seed. Up close you can see its 6 legs, 2 antennae and a striped abdomen. Young bed bugs look like tiny pale or see-through versions of the adult.
What is a bed bug?
A bed bug (Cimex lectularius) is a small, wingless insect that feeds on the blood of people and sometimes animals, usually at night while they sleep. It hides in mattresses, furniture and cracks during the day and spreads by hitching rides in luggage, bags and used furniture.
Can you see bed bugs with the naked eye?
Yes. Adult bed bugs and larger nymphs are easy to see. Eggs and the youngest nymphs are about 1 mm and pale, so they are much harder to spot without a flashlight and a magnifying glass.
What color are bed bugs?
Adults are mahogany or reddish brown when unfed and dark red to purplish after feeding. Nymphs are pale straw yellow or nearly see-through until they feed. Eggs are pearly white.
Do bed bugs fly or jump?
No. Bed bugs have small wing pads but cannot fly, and their legs are not built for jumping. They crawl, and they spread to new places by hiding in luggage, clothes, furniture and bags.
What can be mistaken for a bed bug?
Bat bugs, carpet beetles, cockroach nymphs, fleas, ticks, booklice and spider beetles are the most common look-alikes. Bat bugs are so similar that a professional usually needs to check them under magnification.
What do baby bed bugs look like?
Baby bed bugs (nymphs) look like small versions of the adult, 1.5 to 4.5 mm long. They are pale, whitish yellow or clear, and after feeding you can see a bright red spot of blood through their body.
If I found one bed bug, are there more?
Often, yes. One bug can be a hitchhiker, but where there is one there are frequently eggs and nymphs hidden nearby. Check the bed and furniture for other signs, and have a licensed inspector confirm it before the problem grows.
Bed Bug Control CA
Know it is a bed bug? Do not wait.
Call our team and we will set up a bed bug inspection in your California city, then give you a written quote.
Bed Bug Control CA provides bed bug inspection and treatment. Our licensed technicians perform the treatments.
Sources
- University of California IPM Program, Bed Bugs Pest Notes
- US Environmental Protection Agency (EPA), How to Identify Bed Bugs
- Centers for Disease Control and Prevention (CDC), About Bed Bugs
- Penn State Extension, Bed Bugs
- California Civil Code sections 1954.600 to 1954.605 (AB 551)