Final cut is one of the most misunderstood terms in film, because it sounds like a description of craft and is actually a clause in a contract. It names whoever gets to approve the version that ships.
The right belongs to whoever paid
By default, the entity financing a film controls the version released. A director delivers a cut, and the studio may accept it, request changes, or recut without agreement.
Directors who hold final cut have negotiated that default away, usually on the strength of a track record. It is granted sparingly and often with conditions attached, because the studio is surrendering control of an asset it paid for.
Common conditions include a maximum running time and a target rating, so the right is real but bounded by what the distributor needs to release the film widely.
The director's cut is a defined stage
Guild agreements in the United States give a director a protected period after principal photography to assemble a cut without studio interference. That version is the director's cut in the formal sense.
The phrase later got attached to extended home-video versions, which are often assembled years afterward and are not the same thing at all.
Those extended editions are usually restorations of deleted material rather than a director's preferred structure, since the preferred structure was already the theatrical one.
Editing is a long process of subtraction
An assembly of all usable footage can run far longer than the finished film. The work between assembly and lock is mostly deciding what the story survives losing.
Scenes that read well on paper frequently vanish because they repeat information the audience already absorbed visually. Editors trust the image over the dialogue.
Each removal changes the pace of everything around it, so a cut is revised as a whole rather than scene by scene. A trim in the first act can make a later scene feel abrupt.
Running time is a commercial constraint
A theater can schedule more showings of a shorter film in a day, which affects how much a screen can earn during a busy weekend. Exhibitors weigh that when deciding how many screens to give a release.
That pressure pushes toward tighter cuts, and it is why length caps appear in contracts. The constraint is arithmetic about screenings, not a judgment about attention spans.
Streaming release loosens the constraint, which is part of why films made for streaming often run longer than comparable theatrical ones.
Lock triggers everything downstream
Once the edit is locked, sound design, score, color grading and visual effects all proceed against fixed timings. Changing a shot afterward means redoing work in several departments.
That is why late notes are expensive and why studios prefer to give them during test screenings rather than after lock.
The final cut, in practice, is the last version anyone could afford to change.