Steps

1. 
   Be prepared to combine the signs to reach a conclusion. Turtles from different species may have specific clues to their gender and it is important to know about these possibilities. The best approach to sexing a turtle is to use a combination of the following suggested steps to come up with the most likely gender for the turtle. Bear in mind that some methods are less reliable than others in determining the gender of your turtle. Yet, if all the signs point in one direction, then it's more likely than not that you've found out the gender accurately. However, if the signs are mixed, you may wish to take your turtle to a vet to be certain.
   
   • Wait until the turtle is an adult because it is extremely difficult to sex a baby turtle.^[1] Be aware that you might have to wait years as they grow,^[2] and that turtles are considered to be juveniles until after 5 years of age.^[3]
     
   
   
2. 
   Hold your turtle with care when determining its gender. Flipping over your turtle can hurt him (or her!). Be careful to hold your turtle with a gentle grip and to turn him or her with care and a gradual movement.
   
3. Look at the turtle's tail. Turtles have a hole or vent which is called the 'cloaca' located on their tail. Male turtles have the cloaca located farther away from the body, about half to two thirds the distance from the shell and more toward to the tip of the tail.^[4] Female turtles have the cloaca closer to the body, almost under the overlap of the shell.^[5]
   
   • 
     Examine the thickness and length of the tail. Male turtles often have fatter and longer tails than the female.^[6][7]
     
   
   
4. 

   Check out the bottom
   Look at the bottom or underbelly of the turtle's shell. If the plastron (bottom shell) is convex, goes out, it's probably a female. If its bottom shell is concave (rounded) or goes in toward the inside of the body, then the turtle is most likely a male.^[8] The reasoning behind this is that the female's convex plastron provides more room for eggs, while the male's concave plastron fits better over the female's when mating.^[9][10]
   
5. 

   Claws
   Look at the turtle's front or fore claws. Most male turtles have very long front claws.^[11] Males use these claws in courtship.^[12] Note that the back claws are usually the same for both genders and that claw size doesn't hold for all species of turtles.
   
   • However, if a male is a 'late bloomer' or has been kept in inadequate conditions, the claws may not be noticeably longer.
     
   
   
6. 
   Check the turtle's size. If you have more than one turtle, you can compare the sizes. In most species, the female turtle is larger.^[13] But the difference is usually very small, and you need to keep in mind that there are size variations within a gender too, so only use this sign along with many others.
   
7. Look for species specific clues. Depending on the species of your turtle, there may be other clues. For example:
   
   • 

     Red- eared sliders
     Red-eared Slider: The male's front claws are longer than on the female's.^[14]
     
   • 
     American box turtle: 90 percent of the time, male box turtles have red or orange irises while the female has brown or yellow ones. Also, the female has a tendency to have a higher-domed, rounder upper-shell, while the male has a lower shell with more of an oval or oblong appearance.
     
   • Read How to tell the gender of your sun turtle for sun turtles.
     
   
   
8. 
   Breed, keep separate, or just keep loving your gender clarified turtle. After determining whether your turtle is male or female, you can decide on breeding from there. However, unless you have a rare species of aquatic turtle, breeding is not advised. You will simply have more turtles to look after and that's a big task for most people.
   

Video

Tips

• It may help to look at a diagram of the vent on a turtle's tail in a picture. One great book for doing this is Turtles and Tortoises-A Complete Owner's Manual by Bartlett and Bartlett.
  
• The male has an organ, phallus, or penis (depending on which biologist you read, any term is correct).^[15] The organ may be 'dark - grey, purple or blackish - with an expanded head and a sharp spine at its tip' and it is large when compared with the turtle's size.^[16] It might be seen on occasion when sunbathing or drinking when the front half of the turtle is submerged.^[17] Now you know and this is pretty incontrovertible evidence of your turtle's gender!
  

Warnings

• There are some variations of sea turtles (specifically, the Kemp Ridley, but there may be others) that have no external signs of which gender they are. Speak with a veterinarian specializing in marine animals to discover which gender your sea turtle is.
  
• Wash your hands every single time you handle a turtle. Some turtles carry salmonella and while it won't harm the turtle, it can harm you.^[18] Do not put unwashed hands near your mouth or nose until you've washed with warm water and soap. Make sure children do so after handling turtles too.
  
• Do not flip over your turtle to determine its gender. This is dangerous for the animal's health.
  

Things You'll Need

• Measuring tape (optional)
  
• Vet's or breeder's advice (optional)