Life Expectancy of House Flies

house fly picture

How Long Do House Flies Live?

House flies transform from eggs into adults in 7 to 10 days and one female can lay up to 500 eggs that are deposited in several batches. As a result, the insects produce multiple generations in a short amount of time despite the brief life expectancy of a house fly.

Temperature and Development

A house fly’s lifespan depends on its surroundings and environmental conditions. The pests can remain active all year in warm, temperate locations, but they’re not as productive in cool temperatures.

When house flies reproduce during cool seasons or whenever other conditions extend the larval lifespan, it may take larvae as long as 8 weeks to reach adulthood. In favorable conditions, these pests may mature in about a week and can live for a couple of months if conditions warrant. However, the typical house fly lifespan is much shorter.

What is the Average Life Expectancy of a House Fly?

In general, house flies live between 15 and 25 days. However, these insects cause plenty of trouble despite the brief house fly adult lifespan. Populations indoors can double in size over about a week, magnifying nuisances and health risks for homeowners.


Flies spread salmonellosis and a number of other diseases wherever they go. They’re also annoying to have around. Unfortunately, since house flies are so small, trying to keep them out of homes by patching window screens, sealing cracks in the exterior and keeping doors closed doesn’t always work.

Homeowners who discover house flies living inside or would like to have an outside inspection to identify house fly developmental sources can contact Orkin for help with pest removal and prevention.