How Small a Gap Can Stink Bugs Squeeze Through?

 

Stink bugs can squeeze through gaps as small as about 3 to 4 millimeters (mm) wide, which is roughly the thickness of two stacked credit cards or a little more than 1/8 of an inch. Because of their flattened bodies and flexible exoskeletons, adult stink bugs can take advantage of extremely tiny cracks and spaces in walls, windows, doors, and screens to enter homes or buildings. Nymphs, which are earlier developmental stages of stink bugs and smaller in size, can often fit through even narrower spaces.

 

Why Can Stink Bugs Fit Through Such Small Gaps?

 

Stink bugs, like many other insects, have a unique body structure:

• Flat, shield-shaped bodies – The shape helps them slip into flat, narrow openings with ease.
• Flexible exoskeleton – Though their shells look hard, the exoskeleton is flexible enough to allow temporary 'squishing.'
• Strong legs – They use their legs to push and wedge themselves through tiny openings.

This combination means they can exploit any small imperfection or gap in your home’s envelope.

 

Where Are These Gaps Most Commonly Found?

 

Typical locations in and around your home where stink bugs may enter through small gaps include:

• Gaps around window and door frames
• Spaces under doors without proper sweeps
• Cracks in siding, foundation, and weatherstripping
• Gaps around utility pipes, cables, and vents
• Broken or torn window and door screens

Any opening that you can fit the tip of a pencil into is probably big enough for an adult stink bug to enter.

 

How to Prevent Stink Bugs From Entering?

 

To keep stink bugs out, focus on sealing up all cracks and gaps wider than 1/16 – 1/8 inch (about 2–3 mm):

• Use silicone or silicone-latex caulk to seal cracks around windows, doors, siding, and utility entries.
• Install new or repair old weatherstripping and door sweeps on exterior doors.
• Repair or replace damaged window and door screens.
• Check attic and basement vents for screens and repair gaps or holes as needed.
• Inspect and seal any gaps in the foundation or where different building materials meet.

Even the smallest oversight can allow stink bugs to squeeze in, so methodically check all areas each season, especially before fall when they are most likely to seek shelter indoors.

 

Summary: Stink Bug Squeezing Ability

 

Adult stink bugs can squeeze through extremely narrow openings—specifically, any gap about 3–4 mm (1/8 inch) wide or more. Their unique bodies make them expert escape artists, so thorough inspection and sealing of all possible entry points—no matter how small—is the best way to keep them out.