The 2017 American Academy of Pediatrics (AAP) guideline for assessing "elevated blood pressure (BP) (90 ^th BP percentile)" and "high BP (95 ^th BP percentile)" includes a large number of BP cut-offs based on sex, age and height, which makes it cumbersome to use in clinical practice. We developed and evaluated the performance of a simple table based on a child's height only to assess elevated and high BP in children compared to the reference AAP guideline based on sex, age and height. Data came from 6816 children aged 8-12 years from the U.S. National Health and Nutrition Examination Survey (NHANES) 1999-2016 and 3145 participants aged 5-12 years from NHANES III (1988-1994). Compared to the reference AAP guideline, the simple table had high values of AUC (0.96/0.91), sensitivity (92.7%/83.2%), specificity (99.0%/99.4%), PPV (92.6%/89.3%), NPV (99.0%/99.0%), and Kappa coefficient (0.92/0.85) for screening elevated/high BP when applied to NHANES, and values were similarly high when applied to NHANES III. These findings show that the simple table based on height only performed nearly as well as the reference 2017 AAP guideline based on sex, age and height for assessing elevated and high BP in U.S. children. This simple table may be a useful screening tool to assess high BP in children aged 5-12 years, particularly in a context of mass screening programs.