As a child, Mars spent time impersonating Elvis Presley. This play-act had a major impact on his musical evolution; he later reflected:
I watch the best. I'm a big fan of Elvis. I'm a big fan of 1950s Elvis when he would go on stage and scare people because he was a force and girls would go nuts! You can say the same thing for Prince or The Police. It's just guys who know that people are here to see a show, so I watch those guys and I love studying them because I'm a fan."
He also impersonated Michael Jackson and Little Richard, both of whom are major inspirations of his. Mars was raised on his father’s doo-wop collection — “simple four-chord songs that got straight to the point” and on Little Richard, Jerry Lee Lewis, and Frankie Lymon. The hip-hop productions by The Neptunes and Timbaland, that were played on the radio constantly, also influenced him.
Mars' musical style gravitated initially towards R&B since he was influenced by artists such as Keith Sweat, Jodeci, and R. Kelly. As a child he also took notice of Jimmy Jam and Terry Lewis, New Edition, Bobby Brown, Boyz II Men, Teddy Riley and Babyface. At the same time, he also listened to 1950s rock 'n' roll, doo-wop music, and Motown. In high school, he listened to classic rock groups such as Led Zeppelin, and The Beatles, whose influences can be heard in Mars' work, as well as singers with high voices, like Stevie Wonder and Freddie Mercury. Bob Marley, and local bands in Hawaii, were a major influence and account for his reggae roots. Hip-hop acts like Jay-Z, The Roots, and Cody Chesnutt were among some of Mars' favourites, and have influenced his composition skills. Each of these musical genres has influenced Mars' musical style; he observed that: "It's not easy to [create] songs with that mixture of rock and soul and hip-hop, and there's only a handful of them." Mars also admires classical music.
Other artists Mars has said inspired his work include: Jimi Hendrix, Amy Winehouse, Sly Stone, Carlos Santana, George Clinton, Coldplay, and Usher. Mars has also stated that he is a fan of: Alicia Keys, Jessie J, Jack White, The Saturdays, and Kings of Leon.
Musical style and themes
Mars' music has been noted for displaying a wide variety of styles, musical genres, and influences, including pop, rock, reggae, R&B, soul, and hip hop. His debut album Doo-Wops & Hooligans, a pop record, is influence by these genres. His subsequent release, Unorthodox Jukebox, as with his debut album, is infused with different influences including dance, rock reggae and soul, as well as balladry. Lyrically, the album is different than the former, addressing traditional notions of romance, male chauvinism, and sexuality. The explicit content in the song "Gorilla" caused a controversy in Australia. Many of his songs, particularly on Doo-Wops & Hooligans, reflect "feel-good", carefree, and optimistic sentiments. However, darker subjects are addressed in his songs, detailing failed relationships and self-destructive behaviour. Mars' third album, 24K Magic, is significantly influence by R&B, soul music and funk. Lyrically, the album involve themes of money and sex. Mars has explained his writing process: "I don't sit down and think, 'I'm going to write a song', inspiration hits me always unexpectedly: on a plane, when I'm out or just before I go to bed. An idea will suddenly come to my mind, and sometimes I manage to turn it into lyrics the next day. Sometimes it'll take me one year to get something real out of it. You can’t force creativeness."
Mars claims that his work with other artists has influenced his musical style: " Nothin' on You had a Motown vibe, Billionaire was a reggae acoustic guitar-driven song, though one of my favourites is the CeeLo Green song. I don't think anyone else could've sung that song. And there's Just the Way You Are. If you know my story, you know I love all different genres of music." Mars states that growing up in Hawaii influenced his style, giving the songs a reggae sound. He explains: "In Hawaii some of the biggest radio stations are reggae. That music brings people together. It's not urban music or pop music. It's just songs. That's what makes it cross over so well. The song comes first."
Philip Lawrence, one of his music partners from The Smeezingtons, stated: "What people don't know is there's a darker underbelly to Bruno Mars." Nevertheless, most of his music is romantic and Mars himself says: "I blame that on me singing to girls back in high school".
Mars possesses a three octave tenor vocal range. Jon Caramanica of The New York Times commented that he is one of the most "versatile and accessible singers in pop, with a light, soul-influenced voice that's an easy fit in a range of styles, a universal donor", while Tim Sendra from AllMusic described Mars' vocals on Doo-Wops & Hooligans as "the kind of smooth instrument that slips into your ear like honey." Jody Rosen from Rolling Stone called Mars a "nimble, soulful vocalist" on Unorthodox Jukebox. Jim Farber of the New York Daily News praised Mars' voice due to "the purity, cream and range of mid-period Michael Jackson" in a review of a concert promoting Unorthodox Jukebox. Mars is also able to play drums, guitar, keyboard, bass, and piano. Mars usually plays the instrumentation or part of it, on his albums and on the songs he composes for other artists