The standard canonical text of the Gospel of Mark contains 16 chapters.
Mark is the shortest of the four canonical Gospels by overall length and is divided into 16 chapters in modern Bible editions. Chapter divisions were added long after the Gospel was written, so they are organizational tools rather than features of the original manuscript.
The final chapter, Mark 16, contains the discovery of Jesus’ empty tomb. In many modern Bibles, Mark 16:9–20 is printed with a note because several of the earliest and most important surviving Greek manuscripts end at Mark 16:8. This longer ending includes appearances of the risen Jesus and other material found in later manuscript traditions.
That textual issue does not change the conventional chapter count used in standard Christian Bibles. It does explain why readers may encounter references to a “short ending” and a “long ending” of Mark. The Gospel’s 16-chapter structure is therefore a stable fact about the canonical presentation, while the history of its final verses is more complex.