BMI

Calculate your BMI here-http://www.nhlbi.nih.gov/guidelines/obesity/BMI/bmicalc.htm

Compare it to CDC guidelines- 

Underweight Less than 18.5
Recommended 18.6 to 24.9
Overweight 25.0 to 29.9
Obese 30 or greater   

See tables- http://www.nhlbi.nih.gov/guidelines/obesity/bmi_tbl.htm