The sci-fi thriller The Butterfly Effect follows Evan’s (Ashton Kutcher) travels through time and space in an effort to change his and his crush Kayleigh’s (Amy Smart) lives, and as such, it was given four different endings. Written and directed by Eric Bress and J. Mackye Gruber, The Butterfly Effect is the story of Evan, a college student with a turbulent past who experiences blackouts and memory loss since childhood. In his 20s, Evan discovers he can travel back in time to specific moments with his adult mind inhabiting his younger body.

Evan begins to use this power to change his and his friends' lives, especially that of Kayleigh, who went through a lot of childhood trauma. However, changing the past also changes the future/present, and in the third act of The Butterfly Effect, Evan ends up in a mental hospital. Evan now has irreversible brain damage and no access to his journals, so he can’t go back in time, but he finds an old home movie to make one final trip to the past – however, what happens after that changes depending on the version of the film.

The Butterfly Effect’s Theatrical Cut Ending

The Butterfly Effect’s Theatrical Cut Ending Is The Best For Evan & Kayleigh

The trip to the past that sends Evan to the mental hospital is one where, in order to avoid becoming a double amputee and his mother having lung cancer, he discards the lit dynamite. However, when it’s smacked out of his hand by Kayleigh’s father, she picks it up and it explodes, killing her. At the hospital, Evan learns that his father could also travel back in time like he does, but stopped when he lost the photographs he used to travel. Evan’s father was later institutionalized and killed by guards after attacking a young Evan.

Kayleigh and her brother Tommy are never abused by their father, Lenny is never bullied by Tommy, and Evan never meets Kayleigh and Tommy.

Evan realizes that he and his friends will never have good futures if he keeps changing the past, so he makes one last effort to make everything right. Evan barricades himself in an office where he finds an old home movie from his childhood, allowing him to travel back to the day he met Kayleigh. There, he scares her so she won’t live with her father and instead chooses her mother as her parents are divorcing. As a result, Kayleigh and her brother Tommy are never abused by their father, Lenny is never bullied by Tommy, and Evan never meets Kayleigh and Tommy.

The theatrical cut of The Butterfly Effect ends with Evan waking up in a college dorm with Lenny as his roommate, who has no idea who Kayleigh is. Evan burns his journals and videos so he can never travel again, and eight years later, Evan and Kayleigh walk past each other on the street. They briefly acknowledge each other before they continue walking, reassuring Evan that everything is finally ok for everyone this time.

The Butterfly Effect’s Happy Ending

The Butterfly Effect’s Happy Ending Is Slightly Different From The Theatrical Cut One

One of The Butterfly Effect’s alternative endings is called the “happy ending”, and it adds an extra something to the theatrical cut’s ending. Everything in The Butterfly Effect's "happy ending" is the exact same as in the theatrical cut up until the eight-year time jump at the end. When Evan and Kayleigh walk past each other on the street, instead of looking at each other when the other isn’t looking, they stop and stare right at each other.

Seeing Kayleigh alive and well is confirmation to Evan that he did things right this time, but it’s also enough to give him the confidence to meet Kayleigh again​​​​​​.

Evan decides to approach Kayleigh and they introduce each other. The attraction and chemistry between them are immediate and undeniable, and Evan asks Kayleigh out for coffee. Seeing Kayleigh alive and well is confirmation to Evan that he did things right this time, but it’s also enough to give him the confidence to meet Kayleigh again in a much safer environment.

The Butterfly Effect’s Open Ending

The Butterfly Effect’s Open Ending Is Also Very Similar To The Ones Above

Another ending for The Butterfly Effect is known as the “open ending”. Like the “happy ending”, everything is the same up to the time jump when Evan and Kayleigh walk past each other on the street. This ending is almost identical to the theatrical cut except that Evan hesitates a bit after seeing Kayleigh walk by and ultimately decides to follow her. This ending leaves it open to interpretation whether Evan catches up to Kayleigh and introduces himself or if he decides to drop it and carry on with his life without her.

The open ending of The Butterfly Effect was used in the movie’s novelization, written by James Swallow.

The Butterfly Effect Director’s Cut Ending

The Butterfly Effect’s Director’s Cut Ending Is Too Strange

Perhaps the most controversial and bizarre of all the alternative endings of The Butterfly Effect is the director’s cut one. In it, Evan also barricades himself at the hospital, where he writes a note in case his final trip doesn’t work. Evan finds a home video but not the one from the birthday party he uses in the theatrical ending. Instead, Evan watches the video of his birth, and successfully travels back to that very specific moment – and that’s when it gets very weird.

Evan goes back to when he was in the womb, and because he has his adult mind, he strangles himself with his umbilical cord, so he’s stillborn. While Evan does this, there’s a voiceover of a psychic palm reader who tells Evan that he has no lifeline, no soul, and he was never meant to be. There’s also a voiceover of his mother telling him she was pregnant three times before him, but they were all stillbirths and Evan was her miracle baby, and of Kayleigh saying that she couldn’t stand her father but living with her mother meant never seeing Evan again.

The Butterfly Effect’s director’s cut ending then shows Evan’s mom grieving at the hospital and later jumps a couple of years into the future to show Kayleigh and Tommy arriving at their mother’s home. The final sequence also shows Evan’s parents having a baby girl, Lenny surrounded by friends at his 13th birthday party, Tommy and Kayleigh’s high school graduation, and Kayleigh marrying an unnamed man. As tragic as it is, the director’s cut shows how much everyone’s lives improved without Evan.

What The Butterfly Effect’s Best Ending Is

Some Of The Butterfly Effect’s Endings Don’t Quite Fit Evan’s Journey

Each of The Butterfly Effect’s endings puts the entire movie and Evan’s journey into a new perspective, but the most fitting one is the theatrical-cut ending. Evan gets full closure in it by burning his journals and videos and making sure that he successfully saved everyone from trauma. His final, casual encounter with Kayleigh is also key to his closure, as he gets the assurance that he saved her from a traumatic upbringing and she grew up to be healthy and successful, but he’s also wise enough to know not to get involved with Kayleigh again.

The “happy ending” and the “open ending” ultimately hurt Evan’s character as he would still go back to Kayleigh, and if things don’t go well, he won’t be able to fix it again after all the brain damage he already has. The director’s cut ending is quite popular among fans of The Butterfly Effect, and while tragic, it would mean that the audience just watched the whole journey of a person who was never born.

The theatrical cut ending of The Butterfly Effect is equal parts hopeful, tragic, and fitting with Evan’s journey, and they all get the good future they deserve.

However, one interesting part of the director’s cut ending of The Butterfly Effect is that it implies that Evan’s mother’s previous stillbirths also killed themselves in the womb because they carried the curse. The theatrical cut ending of The Butterfly Effect is equal parts hopeful, tragic, and fitting with Evan’s journey, and they all get the good future they deserve.