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How Fast Do Painted Turtles Grow?

| Updated September 26, 2017

When painted turtles hatch, they are approximately the size of a nickel, but they don't stay that small for long. The top shell, called the carapace, the bottom shell, called the plastron, and even the scales on the top shell, called the scutes, grow along with a turtle's body at a swift rate during the first several years of a turtle's life. Painted turtle hatchling carapaces are 18 to 31 millimeters long, and full-grown adult painted turtle carapaces are 90 to 250 millimeters long.

Stages of Growth

Male and female painted turtles grow at different rates, and the sex of a painted turtle is determined by the temperature during incubation. The threshold temperature is 84 degrees Fahrenheit. Eggs that develop above 84 degrees become female turtles, and eggs that develop below 84 degrees become male turtles.

  • Male painted turtles reach maturity when their plastron is between 70 and 95 millimeters in length. This is generally between 3 and 5 years of age.
  • Female painted turtles reach maturity when their plastron is between 100 and 130 millimeters in length. Females mature between 6 and 10 years of age.

After reaching maturity, both male and female turtles continue to grow, but at a slower rate. They can live to be 35 to 40 years of age.

How the Carapace Grows

A painted turtle's carapace is made out of 13 separate bones; these are the scales called scutes. As a turtle grows, the outermost layer of scutes is shed and replaced by newly grown, larger scutes from underneath.

How to Tell the Age of a Painted Turtle

The scutes on a painted turtle have rings that resemble those in the cross section of a tree. When turtles shed old scutes, the new ones have an added ring. Counting the number of rings on a scute will tell you the age of a painted turtle.

How to Tell the Sex of a Painted Turtle

Female painted turtles are generally larger than males, and they have flat plastrons. Males turtles have concave plastrons. Males also have longer stockier tails and longer front claws.

Interesting Facts

  • As painted turtles grow, their natural habitat changes. They begin life living in shallow waters and move to deeper waters when they become larger.
  • Painted turtles are the most abundant and widespread species in the United States and Canada. They are the only North American species that occurs naturally continentwide.


  • Painted turtles can be a source of Salmonella. The sale of small turtles as pets in the United States is illegal.

    Painted turtles are not recommended as pets for children.