Flea Size and Screen Mesh

Fleas are extremely small, typically measuring around 1.5 to 3.3 millimeters in length. Most standard window screens have a mesh size designed to keep out larger insects like mosquitoes and flies, with a mesh count ranging from 16 to 18 per square inch. However, a typical flea can fit through screens with larger holes. Studies on insect-proof screens in greenhouses highlight that the effectiveness of a screen in blocking small pests depends significantly on the mesh size. Very fine mesh screens are required to prevent entry of smaller pests, including fleas (Bethke et al., 1994).

Flea Mobility and Behavior

Fleas are known for their ability to jump long distances relative to their size, but they cannot fly. They are more likely to enter homes through pets or gaps in doors and windows rather than actively jumping through screens. That said, if the screen is damaged or has large gaps, fleas could potentially get inside. Ensuring that window and door screens are well-maintained and free of tears can reduce the chances of fleas entering your home.

Preventing Flea Entry

To effectively prevent fleas from getting into your home, consider the following:

• Check your screens: Regularly inspect your screens for any tears or gaps. Repairing holes quickly can stop fleas and other small pests from entering.
• Use fine mesh screens: If fleas are a frequent concern, especially in areas with a lot of outdoor pets or wildlife, consider installing screens with a finer mesh. These screens are specifically designed to keep out even the smallest pests, such as fleas and mites.
• Maintain a clean environment: Regular cleaning and vacuuming of carpets, furniture, and pet bedding can significantly reduce the likelihood of a flea infestation. Fleas are more likely to enter homes where pets spend time outside and bring them in.



While fleas can technically get through poorly maintained or inadequately sized screens, ensuring proper screen installation and upkeep will greatly reduce the likelihood of an infestation.

Works Cited

Bethke, J., Redak, R., & Paine, T. (1994). Screens Deny Specific Pests Entry to Greenhouses. California Agriculture, 48(3), 37-40. https://californiaagriculture.org/article/110197.