|Manga Debut||Volume 1, Chapter 0|
|Anime Debut||Season 1, Episode 1: Disband the Club!|
|Videogames||K-ON! Ho-kago Live!!|
|Stages||K-ON!! Let's Go! Live|
|Also Known As||Onee-chan|
|Birthday||November 27, 1991|
|Class||Junior High School|
Senior High School
Gibson Les Paul Standard in Heritage Cherry Sunburst; named "Giita"
Always looking for fun, Yui is fearless; Anxiety and stage fright are unknown to her. She likes everything cute and makes a lot of physical contact with others like holding hands or hugging. She also loves everything sweet, so she's energized by the sweets that Tsumugi brings and her physical constitution is such that she does not gain weight no matter how much she eats. She can't stand being hot or cold, so she spends the winter under the kotatsu  and rolls around on the floor in the summer in front of the fan to keep cool. Yui is rather lazy, so her grades with the exception of fine arts are always on the verge of failing; Sometimes she is the only person in her class who needs to retake a test, while other times she manages to avoid failing all of her subjects by a one point margin. She has an average figure. Yui lives in a family of four with her younger sister Ui and both parents. Her parents are a "lovey-dovey" couple and often go on trips together, leaving both daughters behind.
Having misunderstood that "light music" means "easy music" (like whistling), Yui joined the Light Music Club and picked up the guitar with absolutely no prior experience. She cannot do more than one thing at a time, but to make up for that she can be highly focused on a particular subject and once started, can advance quite rapidly. However, whenever she learns something, she tends to forget everything else. Yui is the type of person who doesn't read manuals and relies on her own intuition and self-taught approaches. She also does not remember any musical terminology. She possesses perfect pitch and is musically gifted, being able to tune her guitar without a tuner, but she does not appear to make the best of her ability. Yui is relatively determined and competitive, but at the same time she feels comfortable depending on the help of a few good friends like Ui, Nodoka, Mio and Azusa.
Yui is a teenager with a slightly below average height of 5'1", with brown eyes and thick medium brown hair at shoulder length, often accessorized with two yellow pins.
Yui is relatively fashion-conscious and prefers styles featured in teen magazines. She wears skirts over pants. She also wears casual clothes such as shorts and t-shirts at home.
Sakuragaoka High School uniform
|Like all Sakuragaoka High School students, Yui wears a school uniform. The Sakuragaoka uniform consists of a navy blue blazer, a solid white buttoned shirt (under the blazer), a colored ribbon (different colors for different student years, Yui's year is light blue), a light steel blue skirt, stockings or socks (Yui's are black), and maroon shoes. The summer uniform replaces the blazer with a beige waistcoat. Additionally, the subject physical education requires a tracksuit (sport jacket with long pants, colored again depending on the year group) with white striped brims, a white shirt with colored endings (again with color identifying the year group) for the summer semester and white sports shoes.|
"Don't say 'lazy'" Attire
|Yui's "Don't say 'lazy'" attire consists of a white knee-length dress with black frills. Large pearl necklaces (bluish grey in color) are used as shoulder straps. Her right arm is wearing a solid black arm glove. Her stockings are vertically striped in black and white. She also wears a pair of white high-heeled shoes with a black and burgundy bead. Yui's hair is done more shaggy and decorated with a white frilled flower that contains two purple beads.|
|In "Listen!!", Yui wears a black shirt under a white one with a washed-out "kiss mark" over a blue lightning bolt print. She also wears blue jeans and maroon boots with black laces. Yui is decorated with green hoop earrings and a bracelet. She also parts her bangs to the left without her two yellow pins, leaving her bangs covering her left eye.|
"NO, Thank You!" Attire
|In "NO, Thank You!", Yui's attire is similar to any school uniform dress code. Her attire is very similar to the Sakuragaoka High School uniform - navy blue blazer and a white buttoned shirt (under the blazer). The only parts different are a "HTT-logo" pinned to her blazer, a plaid grey skirt, a red tie, dark blue socks and her brown shoes.|
|Yui's second attire in "NO, Thank You!". She wears a plain solid white tank top with a blue pin near her right shoulder and a red knee height skirt.|
|Yui's "Singing" attire. Like the rest of the band, she wears a light blue one-piece dress over a white shirt. The skirt goes down to her knees. The dress has four white dots over the chest, a white bow and a white collar. Additionally, Yui wears black shoes with white shoelaces over long white socks, which have red and blue stripes on them. She also wears a black pair of glasses. Her hair is tied up to two short braids.|
|Yui's second attire in "Singing". She wears a black hoodie (which is decorated with two "ears") over a pale orange shirt which is covered by a second, pale pink shirt that has three stars on it. She also wears black flap trousers with three holes that show the shirt she wears underneath. Additionally, she wears two green earrings, grey tights with black lines on them and black shoes with white laces.|
Character Image Songs
|K-ON! Character Image Song Series Vol. 1: Yui Hirasawa||K-ON!! Character Image Songs: Yui Hirasawa|
- The name Yui means "solely, only" (唯).
- Yui's surname Hirasawa means "flat" (平) (hira) and "marsh" (沢) (sawa).