By Gary Anderson|August 26, 2025|5 min read

How Long Do Flies Live?

Understanding fly lifespan and life cycle helps control their population effectively.

It is a common misconception that flies only live for 24 hours, but that is only true for certain species like mayflies. House flies and other larger fly species can live for several days or even months, making them harder to manage.

Flies are carriers of pathogens and bacteria that can contaminate food and cause illness. Understanding their life cycle helps control their population effectively.

The Short Answer

House flies typically live 15 to 25 days. In optimal conditions, they can survive up to 2 months. Without food, flies can only survive for 2 to 3 days. A single female can produce up to 3,000 eggs in her lifetime.

Lifespan Quick Facts

House Fly: 20-30 days

Fruit Fly: 40-50 days

Horse Fly: 30-60 days

Gnat: 7-14 days

Mosquito: 10-14 days

Understanding the Fly Life Cycle

The fly life cycle starts with the egg and develops through the larval and pupal stage before reaching adulthood. Flies can go through their entire life cycle in 15 to 30 days.

Eggs

Females lay 70-200 eggs at a time, up to 500 in a few days. White, 1.2mm long. Hatch in 8-20 hours. Ideal temp: 25-30°C.

Larvae (Maggots)

Pale, worm-like with tiny black hooks. Feed on animal remains, manure, garbage. Grow to 7-12mm. Stage lasts 3-7 days (up to 55 days in poor conditions).

Pupae

Dark brown oval with blunted ends. Do not move or feed. Develop wings, antennas, legs. Takes 2-6 days (high temp) or 17-27 days (low temp).

Adult Flies

6-7mm long, live 15-25 days (up to 2 months optimal). Sexually mature within hours. Sleep at night due to poor dark vision.

How Do Flies Reproduce?

Mating Process

Flies mate within hours of emerging from pupa. Males initiate courtship lasting 30 minutes to 2 hours. Copulation takes 2-15 minutes.

Egg Laying

Females lay 75-200 eggs per batch, multiple batches over days. Eggs laid 4-20 days after mating. Require protein for egg production.

Rapid Multiplication

Single female produces up to 3,000 eggs in lifetime. Lays eggs 5-6 times, up to 120 eggs each time. One fly quickly becomes infestation.

Flies Multiplying in Your Home?

A single female fly can produce thousands of eggs. Stop the infestation before it grows.

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Fly Lifespan by Species

House Fly

20-30 days

Females lay 5-6 batches of eggs. Eggs hatch 12-24 hours, larvae feed 4-7 days, pupae develop 4-6 days. Can live up to 28-30 days in optimal conditions.

Fruit Fly

40-50 days

Longer lifespan than house flies. One female produces up to 500 offspring. Can develop from egg to adult in as little as one week.

Horse Fly

30-60 days

Larger than house flies. Eggs laid on grass in fall, larvae develop over winter, pupate in spring. Adults emerge by early June.

Tsetse Fly

30-120 days

Females live 1-4 months, males only 2-3 weeks. Unique reproduction: female carries larvae 9 days before birth. Found only in Africa.

Gnat

7-14 days

Shortest-lived of common flies. Despite resemblance to baby flies, gnats are a distinct species. Life cycle lasts 1-2 weeks.

Mosquito

10-14 days

Eggs laid in stagnant water. Larvae live in water until pupae stage. Cooler temps: up to 14 days. Warmer temps: around 10 days.

How Long Can Flies Live Without Food?

Without Food

Flies can only survive 2-3 days without food. They need high-calorie content (sugars and proteins) and certain proteins for egg production.

Hydration

Hydration is critical to survival, but flies usually extract moisture from food sources. Without food, they quickly dehydrate.

In Your Home

Flies can survive up to 4 weeks indoors with food available. Some flies can overwinter in homes for several months.

How to Prevent Flies

Wipe down surfaces regularly

Store food properly in sealed containers

Fix leaks to eliminate water sources

Take out trash regularly

Seal windows and doors

Fix damaged window screens

Clean drains and sink areas

Fill cracks in walls and foundation

Contact EcoGuard if You Are Dealing with a Fly Problem

If you are tired of dealing with pesky flies in your home, you are not alone. At EcoGuard Pest Management, we understand how stressful it can be. Our team will inspect your property for problematic areas and provide treatment and guidance on how to prevent further fly activity in the future.

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Fly Lifespan FAQs

How long does a fly live inside a house?

A fly's indoor life expectancy if it can avoid being detected is typically between 2-4 weeks. The time can fluctuate depending on environmental factors like temperature and humidity as well as resource availability.

How long do flies live indoors without food?

No matter where a fly is, it can only survive for 2-3 days without food to replenish valuable nutrients and moisture. After a couple of days without food, the flies will succumb to exhaustion and die.

Do flies sleep?

Flies that are still could possibly be sleeping but it is unlikely. Any fly that is asleep would become active the second it detects your presence. Flies are not nocturnal and will sleep at night because their vision in the dark is poor.

Do flies hibernate?

Flies become much less active during winter months in areas where temperatures drop low. They will seek out shelter where they can overwinter and will become active again once temperatures start to rise.

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