Box office In the opening day of its release, the film collected on first day, despite competing with
Bigil. At the end of the first week, the film collected about at the box-office.
International Business Times published that the film had collected worldwide in the first 10 days, with from Tamil Nadu, in
Kerala, close to in
Andhra Pradesh and
Telangana and over in
Karnataka. On 12 November 2019, the makers officially announced that the film had collected worldwide, thereby becoming Karthi's first film to cross the
100-crore mark. Owing to its critical response, it was featured in many year-end lists as one of the best
Tamil films of 2019 by several publications such as
The Indian Express,
Film Companion South,
Hindustan Times,
Sify,
Firstpost and
India Today. Calling it as a "tense and impressively shot action thriller", M. Suganth gave 4.5 stars (out of 5) in the review for
The Times of India, and stated "Lokesh Kanagaraj gives us a pure genre film minus the frills, like songs and romance, that we are used to in Tamil cinema". Though he concerned about "the film which feels overlong for its genre, as a couple of action blocks getting over-indulgent" but concluded "when it is action that we have signed up for, we cannot complain much about that". Janani K of
India Today gave four out of five stars stating, "
Kaithi is a film that showcases filmmaking at its best" and praised Karthi's performance as "terrific and natural that one could literally picture a prisoner going through a tough time". Sreedhar Pillai of
Firstpost gave four-and-a-half out of five stars rating to the film saying "
Kaithi is a well made film that takes the road less travelled and provides enough thrills". He further added that "Karthi's raw and intense performance, the film's taut screenplay and excellent technicality, along with awesome action scenes, makes
Kaithi an edge-of-the seat thriller".
News18-based critic Gauthaman Bhaskaran gave three out of five stars stating "Karthi's stunning performance makes it an engaging watch". Manoj Kumar R. of
The Indian Express gave 3.5 stars (out of 5) stating, "Karthi has essayed his role in an almost self-effacing manner while allowing the space for other people's acts of courage in the narration to get their due screen time. Kaithi is the director's canvas. It is necessary to appreciate Karthi to let Lokesh do his thing without trying to bend the narration to suit his star image. The director softly but firmly announces himself as a major new force in the commercial space of the Tamil film industry, which still largely feeds on the narrow definition of mainstream entertainment." S. Srivatsan, writing for
The Hindu, stated the film as "one of the best action thriller ever made since
Theeran Adhigaaram Ondru". Further reviewing that "
Kaithi does have its 'mass' moments, but there is a certain level of screenwriting that has gone into conceiving those. The plot contains all the elements of a conventional suspense-thriller, but where
Kaithi differs is by how Lokesh Kanagaraj treats the genre and its audience with respect." Karthik Kumar of
Hindustan Times stated it as "an action film with a soul and a purpose" while also stated that "though it is not a crowd-pleasing commercial film, it still caters to the masses".
Sify gave three-and-a-half out of five stars stating "Kaithi is a solid action thriller and it will be a feast for action lovers". Calling it as "brilliant" and "engaging thriller", Anupama Subramanian of
Deccan Chronicle gave four out of five, saying "Kaithi with its solid story combined with outstanding performances and flawless making is set to stand the test of time".
The News Minute-based editor-in-chief, Priyanka Thirumurthy, gave four out of five stating "There is no star in Kaithi, as director Lokesh shows that a hero is anyone who goes beyond thinking about just himself."
Baradwaj Rangan wrote for
Film Companion, "
Kaithi is certainly a sturdy vehicle for Karthi, who – as
Theeran Adhigaaram Ondru so memorably demonstrated – is one of our few actors who can do both
Clark Kent (through his face) and
Superman (through his stocky frame). There's a fantastic "mass" scene, set around a swimming pool, where Dilli stuffs himself with biriyani – it's a stunning few minutes of a purely
physical performance. It's strange how this Karthi looks and sounds so genteel and urban in real life, but his best work on screen is when he's got a bit of animal inside him." == Accolades ==