Factual error: Dr Schultz pays with 12 $1000 bills, but $1000 bills were not created until 1861, after the time period of this movie.
Factual error: The film is based in 1858 and proceeds through the winter into the spring of 1859. At the end of the movie Django blows up Candyland using dynamite. Dynamite was not invented by Alfred Nobel until 1864 and then patented in 1867.
Factual error: During the "skull monologue", Calvin Candie mentions "genes". The word was coined after 1905 from the work of Danish scientist Wilhelm Ludvig Johannsen. Genetics were born with Mendel's work, which was published in 1866 and did not become widely known in the scientific community until decades later.
Character mistake: The check written by Sam Jackson says May 2, 1858. At this point in the movie, it should be 1859.
Continuity mistake: The amount of beer in the glass during the first beer scene in the movie changes between shots. It is half full, then after a while it is almost full again.
Factual error: The "Cleopatra Club", where Django, Schultz and Monsieur Candie meet for the first time, uses an Egyptian sculpture replica as a trademark, which resembles the famous Nefertiti bust; this was only discovered in December 1912, by a German archaeologist.
Continuity mistake: During the first shootout scene inside Candiland, when Django rolls off Leonide Moguy (Candie's Lawyer) he rolls to the right of the shot, away from the room he had just come from. However in the next scene when the door is kicked in we see Django moving and shooting from the opposite side of the room, towards the side he should already be.
Continuity mistake: When Cora and Sheba are leaving the house, they are using the left panel of the double door, opening it inward. But when Django leaves the house, using the right door panel, you can see an astragal (the seal between a pair of doors) attached to the far side of the left panel. This would have prevented the left door panel from being opened inward as Cora did.
Continuity mistake: After first arriving at Candieland, Calvin Candie is explaining to Steven who Django is and that they will be staying in the big house. During this scene, cuts between Calvin and Steven show Calvin's legs alternating between crossed in one angle and uncrossed in the other angle, multiple times. The lawyer's arms also go from being crossed to uncrossed when Calvin does the introductions between Django and Steve.
Factual error: In several scenes throughout the film, characters are shown wearing pants which have belt loops. While belts were used in the past, belt loops on pants did not come into usage until the 20th century.
Continuity mistake: In the scene where Schultz shoots the sheriff, as he walks away he has blood on his hand and his jacket. The blood is gone from both in the next shot and from then on.
Continuity mistake: In the scene where Django shoots Smitty Bacall, the plough that he is using can be seen on the far left of the field and moving at a slow pace. But when Dr Schultz puts his wanted poster away, the plough is suddenly on the far right of the field having not had enough time to have turned round and moved that far.
Visible crew/equipment: When Sheriff Bill Sharp steps out into the street you can see a hearing aid in his left ear.
Factual error: In several closeups (especially of Leonardo DiCaprio) it is clear that some of the characters are wearing plastic contact lenses in their eyes. These were not invented until the late 1970s.