How do you check your height accurately without the doctor?

My daughter is about 26 inches tall and she turned 3 years old August 2nd this year. We have taken her to the doctor to check her height and the doctor said that her bones grow a lot slower than they should. WHAT'S THE AVERAGE HEIGHT FOR A 3 YEAR OLD?

• Answer:

  * Growth is steady though slower than in first two years. * Height increases 5 cm to 8 cm per year ; average height is 95 cm to 100 cm, nearly double the child’s birth length * Adult height can be predicted from measurements of height at three years of age; males are approximately 53% of their adult height and females, 57%. * Weight gains 1.4 kg to 2.3 kg per year; weight 13 kg to 17 kg.