Determining the age of a turtle is not an exact science, however, some tricks will help you estimate the age of your pet easily. Counting the rings on its scute and comparing the size of your turtle with others from the same species can give an estimate of age. Observe the rings on the scute of your animal's carapace and count them. Then divide the result by two. Another method is growth. This works particularly well in young individuals as they grow at a more defined pace. Measure the length of your turtle from the tip of its shell to the end then compare the results with a growth chart for their species.