Other mistake: At the start, we see PT Barnum in the shadows. However his waistcoat is lit up in one shot despite the lights all being behind him. (00:00:40)
Visible crew/equipment: While Barnum and Phillip sing "The Other Side" Phillip uses two stools to get up and down from the bar top. When he steps down from the bar top, in this wideshot (also the first shot of them in the pub and other shots) the two upright stools Phillip used are secured with additional support, note the floor area underneath the stools' legs have the same pattern as the rest of the floor, though we can see the outline where the pattern's lines don't match up. Additionally, we also see three actors' marks (in the shape of an "L") on the floor in front of the bar, which will be where Barnum and Phillip will stand when they agree on the ten percent. (00:36:05)
Continuity mistake: During the "This is me" sequence, the tattooed man is wearing a red cape. During the last few seconds of the song, he loses the cape and then it reappears again. (00:59:55)
Continuity mistake: When Barnum goes to see Charity by the beach at the end of the film, they embrace. As the camera shows a close up of their faces Charity's head is on Barnum's right shoulder, but when they reverse the shot to show her expression she is now on his left shoulder. (01:30:10)
Continuity mistake: When Jenny Lind is first introduced and is walking in, she doesn't have gloves on. When PT Barnum and Phillip Carlyle kiss her hand she's wearing formal gloves. (00:44:35)
Revealing mistake: While Barnum and Phillip are singing "The Other Side" Phillip knocks over the first stool then steps on its side, and in this closeup we can see the extra two flat bars attached between the legs, for him to easily step on. We also see that the stool's seat is perfectly round in the closeup, but in previous and following shots, such as when Carlyle jumps off the bar then grabs his hat, one side of the seat has been cut to allow it to rest flat on the floor while on its side. Presumably, the closeup was digitally edited to make the seat appear round. (00:38:05)
Continuity mistake: When Barnum is writing a letter to Charity near the start he is right handed. When we see him just before he is fired he is left handed. (00:06:45 - 00:11:00)
Other mistake: When Jenny Lind is on stage singing 'Never Enough' during her American debut, she is in a very large theater with a crowded audience, and full orchestra. Obviously she would have to be miced, and have her voice amplified, for such a large space. When she is actually singing, her character's voice (or rather the dubbed voice of Loren Allred) is greatly amplified, with sound effects. But during this actual scene, there is no microphone or amplification system present. She does not have a microphone stand in front of her. There is no microphone hanging from the ceiling, or anywhere on stage that we can see. Technology was limited at that time, so she would not be using any type of cordless headset, or wireless microphone, which cannot be seen anyway. Her character's voice is obviously amplified a great deal through a microphone, which doesn't seem to exist.
Continuity mistake: At the start of Come Alive, PT stands in front of his museum and is on a wet patch of ground. Camera cuts and now the floor is dry. (00:25:15)
Factual error: When they go to visit the Queen, the Union flag is being flown above Buckingham Palace. The Union flag is only flown when the Queen is not in residence. As the Queen is in residence, the 'Royal Standard' flag should be flown. And anyway, the Union flag has only been flown at the palace since the death of Princess Diana in 1997. (00:43:00)
Continuity mistake: PT arrives home to tell Charity that he's been fired. Depending on the angle, a long strand of hair falls over her left cheek or not. This keeps swapping back and forth. (00:12:50)
Continuity mistake: When young PT makes young Charity laugh, she spills tea over her dress, leaving it soaking wet. When the angle changes it's almost dry. (00:03:50)
Continuity mistake: Throughout Rewrite the stars, the marks on Phillip's trousers are constantly changing between shots. (01:03:00)
Visible crew/equipment: Near the end of Come Alive, one of the dancers in a white dress spins around, and when she does so, what appears to be a black mic pack is visible on her back. This black item is not visible in other shots of her during the song.
Continuity mistake: When the song "the Other Side" starts, Hugh drinks his shot with his right hand. It cuts to a side shot and Hugh drinks his shot with his left hand. Then back to the front shot, and again he drinks his shot with his right hand.
Factual error: The bottle of Moet champagne is a very modern design - the 1850's design was a similar bottle shape but had a different style of label. (01:09:00 - 01:10:00)
Continuity mistake: When Charity's father slaps young Barnum for making her laugh he is wearing the partially tailored suit. Then he walks past him an instant later and he is not wearing it.
Audio problem: During "This is me", when they enter the room and get to the "oooh oh oh" part if you watch the albino the sync is out as their mouths open after the music has ended on that part.
Continuity mistake: During The Other Side, the peanut shells keep appearing and disappearing between shots. (00:37:05)
Continuity mistake: When PT is showing the family his museum, he picks one of the girls up with her facing him. Camera changes and now she's facing away from him. (00:18:00)
Answer: It doesn't tell.