The identification of elevated blood pressure (BP) in children and adolescents relies on complex percentile tables. The present study compares the performance of 11 simplified methods for assessing elevated or high BP in children and adolescents using individual-level data from seven countries. Data on BP were available for a total of 58,899 children and adolescents aged 6–17 years from seven national surveys in China, India, Iran, Korea, Poland, Tunisia and the USA. Performance of the simplified methods for screening elevated or high BP were assessed with receiver operating characteristic curve (area under the curve, AUC), sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV). When pooling individual data from the seven countries, all 11 simplified methods performed well in screening high BP, with high AUC values (0.84 to 0.98), high sensitivity (0.69 to 1.00), high specificity (0.87 to 1) and high NPV values (≥0.98). However, PPV was low for most simplified methods, but reached ~0.90 for each of the three methods including sex- and age- specific BP references (at the 95th percentile of height), the formula for BP references (at the 95th percentile of height), and the simplified method relying on a child’s absolute height. These findings were found independently of sex, age and geographical location. Similar results were found for simplified methods for screening elevated BP. In conclusion, all 11 simplified methods performed well for identifying high or elevated BP in children and adolescents, but three methods performed best, and may be most useful for screening purposes.