How Long Does it Take Tadpoles to Turn into Frogs?

Written by Katelynn Sobus
Published: February 28, 2022
Image Credit iStock.com/Suwatwongkham
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Whether you’re raising tadpoles for the first time at home or have come across them outdoors, you may be impatient to watch them grow! Maybe it’s taking longer than you expected and you’re worried about your frog babies’ health.

Tadpoles typically turn into froglets within 9-12 weeks and develop fully in 12-16 weeks. This varies based on species and temperature, with some tadpoles taking up to eight months to develop fully.

In this guide, we’ll discuss everything there is to know about tadpoles and their life stages, how long they take to turn into frogs, and more!

How Long Does It Take Tadpoles to Turn Into Frogs?

Giant Burrowing Frog changing from tadpole to frog
Most tadpoles in North America take 12 to 16 weeks to transform into a frog.

Ken Griffiths/Shutterstock.com

Most tadpoles in North America turn into frogs within 12-16 weeks. Exactly when they transform depends on a few factors, including species and temperature.

Some frog species develop more slowly than others. In fact, it can take a tadpole up to eight months to turn into a fully-grown frog!

Temperature also affects a tadpole’s ability to undergo metamorphosis.

In cold weather, frogs go into hibernation. They will often dig underground or rest at the bottom of a body of water to keep themselves warm. Their metabolisms slow down so that they can get through the winter using the energy they’ve stored throughout the year.

Tadpoles don’t have this “storage” yet, though, and hibernation wouldn’t be safe for them due to this. Therefore, they’ll stay tadpoles until the temperature goes up again instead.

How can you Tell how Old a Tadpole is?

You can guess a tadpole’s age based on its development. If the tadpole still has gills, a tail, and no legs—looking nothing like a frog—it’s likely under four weeks of age.

Tadpoles that aren’t yet swimming or eating are, at most, a few days old.

Four-week-old tadpoles are fierce carnivores (well, as fierce as they can be at their size!) with back legs, developing lungs, and teeth.

A tadpole with front legs that looks very frog-like is actually a froglet and is 9-12 weeks old. Once a froglet loses its tail, it’s considered a fully-grown frog.

A frog that lays eggs is at least three years old.

Tadpole to Frog Stages

What Do Bullfrogs Eat?
Tadpoles are born without any legs and have gills.

iStock.com/Suwatwongkham

Stage One: Frog Eggs

A frog’s life begins in an egg. These are transparent, with no shells, and typically laid in the water. Some species will lay their eggs on land, but this isn’t common.

Frog eggs look kind of squishy, similar to fish eggs. You can see the little tadpoles inside—of course, they look nothing like frogs yet!

These eggs are laid in large quantities (up to 20,000 eggs!) and take anywhere from three to twenty-five days to hatch.

Many of these eggs won’t hatch into tadpoles because they are eaten by predators first!

Stage Two: Tadpoles

Sadly, a tadpole’s survival isn’t guaranteed once they’ve hatched from their eggs. They are still delicate, small creatures that make easy prey for other fish and aquatic life.

When they’re born, tadpoles don’t have any legs. They look a lot like fish, with tails and gills.

For the first few days, these delicate creatures can’t even swim. They survive from the jelly from their own eggs until they can finally seek out algae. This will be their only source of food until they’re older.

A lot of development happens in this stage. Within about four weeks, tadpoles begin to grow teeth, lungs, and legs. At this point, their diet also changes and they begin to eat everything they can! They’re fierce but small hunters.

As a tadpole develops its front legs, it begins to look like a frog and is called a froglet. Froglets are 9-12 weeks old.

Of course, this guessing game is complicated by temperatures in your area. If the tadpoles are housed outside, they may take all winter to develop into frogs. This is because they cannot undergo metamorphosis until the temperatures are warmer and adult frogs emerge from hibernation.

This slowed development will affect how a tadpole looks at any given age, so a tadpole at one of the stages described above may be older than stated if it’s cold outside or has recently been chilly in your area.

Stage Three: Froglets

During the froglet phase, the lungs strengthen and the gills disappear. A froglet has legs, looks a lot like a tiny frog, and is officially ready to live on land!

They also grow their tongues during this time, but they don’t lose their tails just yet. At this stage, they are in the process of absorbing their tails so that they can grow into fully-developed, adult frogs.

Stage Four: Fully-Grown Frogs

Once a froglet has absorbed its tail, it is officially a frog! It will take a few years until the frog becomes fertile, at which time they’ll lay their own eggs and begin the life cycle all over again!

What do Tadpoles Need to Survive?

Swimming tadpoles
The tadpole gradually changes into its frog form.

Joshua Ouellette/Shutterstock.com

Tadpoles need water to live in, and they prefer a warm environment—this will also cause them to grow quicker than they would in cold weather. Add a filter if keeping tadpoles in an aquarium.

For the first few days of life, a tadpole won’t eat or swim, surviving only on the nutrients from its shell. Then, it will eat algae—or, in captivity, tadpole food.

Once your tadpoles have teeth, they can eat just about anything. The RSPCA recommends rinsed frozen greens. Tadpoles also eat insects and smaller fish.

Remember that tadpoles will need room to grow, meaning that you must keep them in a large space or upgrade their habitat as they age. Another consideration is that, once tadpoles turn into froglets, many species will emerge from the water onto land.

You want to allow for this so that your frogs don’t eventually drown.

Why Wouldn’t Tadpoles Turn into Frogs?

If your tadpoles aren’t turning into frogs, you likely aren’t doing anything wrong—and they will grow up eventually!

It may be too cold for them to metamorphasize. Because tadpoles can’t hibernate, they won’t grow into frogs until temperatures warm up again. This keeps them alive during the winter months.

Another possibility is that you haven’t given them enough time. Some frog species take up to eight months to develop, so be patient!

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About the Author

I'm an animal writer of four years with a primary focus on educational pet content. I want our furry, feathery, and scaley friends to receive the best care possible! In my free time, I'm usually outdoors gardening or spending time with my nine rescue pets.