How do you determine the correct size bike you should get your child?

Question

How do you determine the correct size bike you should get your child?

Answer 1

Have your little one sit on it. Make sure his/her feet can touch the ground and he/she can reach the handle bars comfortably.

And don't forget the helmet.

Answer 2

It's a bit different than sizing an adult's bike and depends on the age and skill level.  For a young beginner, you want them to be able to touch the ground with their feet so they can become comfortable.  It is certainly not the most efficient cycling position, but it works for them.  As they improve, you can approach a more efficient seat height where the feet touch the pedals while sitting on the seat, but don't reach the ground.  

And make sure all kids bikes have a frame that has a "women's" style upper tube so they don't injure themselves by straddling it hard.