Purpose: The principal objective of this study was to evaluate the power output of ultrasound in Korean clinics and compare the value with Korean and global standards. Methods: A total of 69 units were measured for ultrasound power output. The normal range of power output level was ${pm}30%$ of the output set according to KFDA standards. Device model, manufacturer, ERA, and BNR were obtained via simple questionnaires. A portable ultrasound power meter was used for output measurement. Results: 37 machines, with reported ERA values, were assessed for power output per unit area. Of these machines, 13 (37.14%) were considered to be compliant with US FDA standards at 0.5, 1.0, 1.5, $20W/cm^2$ and 18 (51.43%) were considered within KFDA standards. The remainder of the machines were outside the standard error and evidenced irregular output levels, even though most of them were the same model. Conclusion: Appropriate ultrasound intensity is incredibly important for safety and effective use. Therefore, the KFDA standards regarding ultrasound may require revision in light of global standards, including BNR and ERA additionally, attention should be paid to regular calibration for safe use in clinical practice.