"Upgrade U" was generally well received by music critics, some praising Knowles' assertiveness while singing about her ability to improve her man's life (to one of extravagant luxury) with her presence. Many also praised the natural chemistry that Knowles and Jay-Z have in the song. After the release of "B'Day", "Upgrade U" started to gain popularity on R&B and hip hop radio stations in the United States. This prompted its pre-release debut on the US Hot R&B/Hip-Hop Songs chart and later on the US "Billboard" Hot 100 chart; after its promotional release, the song peaked at number 11 and at number 59 on the Hot R&B/Hip-Hop Songs and the Hot 100 charts respectively.