In this thread I'll try to point out all differences between the adaptation and the original.
For those who do not want spoilers, the main gist is:
The anime is based on the first 14 chapters (First two volumes), with parts of chapter 15.
The anime is made in a way to not need a narrator, which the manga has.
The anime rearranges, expands and modifies events in order to have a "status quo", while in the manga the story is always "flowing".
In the anime, the relationship between the main-character has a "logarithmic behavior" (Grows very fast near the start, and then the growth becomes very slow), while in the manga is is more "linear". Granted, this is somewhat subjective.
The manga makes some small details more clear, though many of your favorite scenes from the anime might not be there.
BTW, noteworthy changes will be in bold text.
Without further ado, let's start:
Covering chapters 1 and 2.
The manga starts with a brief overview of the Victorian setting. The anime starts with Emma cleaning the house.
In the anime, William hesitates before trying to knock on the door and then gets hit by it on his face. In the manga, he doesn't hesitate, and just gets hit by the door when trying to knock.
The stray cat isn't there on the manga (The anime makes them a quite recurring character, while in the manga he only appears once, many chapters later) therefore William's hat just tumbles through the street instead of being stolen by the aforementioned feline.
Some lines have their order changed (For the sake of brevity and my sanity, I won't comment when this happens from now on unless it is REALLY important)
In the anime, Mr. Graham knocks on the door (It's actually a mailman, though), while in the manga, he calls Mrs. Stownar by telephone. (I assume that minute changes like that are due to the anime having an specialist on historic accuracy)
In the anime, Jones takes the initiative to talking to Emma. In the manga, it is the other way around.
In the manga, Emma tells William that Mrs Stownar never mentioned him, and Emma couldn't tell it was William in the photo despite looking at that photograph every single day. In the anime she remarks how Kelly would always talk about him, and she quickly knew it was him there.
William tried to call her for a date before being interrupted by Kelly in the manga. This doesn't happen in the anime.
In the anime, William accidentally forgets his gloves. In the manga, he leaves them there on purpose.
Due to that, in the anime, Kelly initially says that Emma shouldn't try to run after him to deliver his gloves, but changes her mind upon seeing Emma's face (Indicating that she wanted to meet him). In the manga, she changes her mind because she quickly notices it was William's plan.
Due to that, this is where they first go take a stroll in the park together in the manga, which in the anime is moved to near the middle of the events of chapter two, when William asks Emma about her glasses.
In the manga, we learn that Emma's vision got worse with time.
In the anime, Emma receives a love letter from the mailman. In the manga, this happens on chapter 4.
In the anime, William already has his miniature airplane, while in the manga he receives it from his maid.
Emma turning down her love letters in the anime is also something that only happens later in the manga.
In the anime, William hears Al complaining about Mrs Stownar being "a slave-driver" (Which doesn't make much sense there). In the manga, this is something that Al himself tells Emma on chapter 5.
The "Martin & Sarah" scene isn't there in the manga. (In fact, the place never becomes "a hotspot" in the manga).
The umbrella scene doesn't happen in the manga.
There are also no comments about the flowers in the manga.
Covering half of chapter 7 and a small part of chapter 9 (It's complicated).
As previously stated, "Martin & Sarah" isn't a recurring place in the manga, so William and Emma's rendezvous there, as well as their walk home and the talk about the gloves are all anime original.
In the manga, William's siblings only return on chapter 9, therefore every scene with them from now on is either relocated or anime original (Also, almost all scenes involving Collin are anime original).
William's father pressuring him to go to the Ball happens on chapter 7.
Also from chapter 7, William's Dance with Eleanor has some expanded dialogue in the anime.
Emma buying groceries is also from chapter 7. However, the specific dialogue from chapter 7 will only happen at a episode 6.
The entire second half of the episode is anime original: The whole "Parasol" plot as well as the maids gossiping.
Covering chapters 3, 4 and parts of chapter 9.
The bridge scene is anime original.
William's dialogue about work is slightly changed.
Since William's siblings were still not introduced at this point on the manga, their talk with Hakim is from chapter 9.
Hakim's bedroom scene is anime original.
Al's cheating scene is also anime original.
Hakim's scenes giving Emma a ride and having dinner with the Jones family are anime original.
In the anime, Emma seems uncomfortable from having her face called pretty, though the reason isn't explained. In the manga, she responds with "I've been through a lot, so..." (Foreshadowing).
Her dialogue with Hakim is slightly expanded on the manga (Quite rare to be the other way around, huh?).
A manga scene on "Martin & Sarah" is cut from the anime.
In the anime, we have a scene were William is at a place where someone asks him about Hakim. In the manga this scene is changed, and it's mostly about low-class men in the background talking about Emma (Remember, the part where we learn that she receives love-letters comes from this chapter).
In the manga, we have an epilogue where the guy William was talking to is asking a girl for a date.
In the anime, we see both William and Emma pondering upon the moonlight. In the manga, it's only William.
Covering most of chapter 6.
The maids chitchatting about Hakim is interrupted by an older maid in the manga. In the anime, it's interrupted by Hakim driving a car.
In the manga, William wants to ask him about his encounter with Emma, but is interrupted. No such scene is there in the anime.
In the anime, Kelly asks Emma to borrow a book after talking to her about Hakim. In the manga, Kelly asks that after talking to her about her watch.
In the anime, Emma borrows two books. In the manga, she borrows three.
In the anime, she borrows one book under her name and one under Kelly's name. In the manga, all three are borrowed under Kelly's name.
In the manga, some parts of the dialogue refer to events that happened on chapter 5. Since they still haven't happened in the anime, those parts are skipped.
All the rest of the episode is anime original: The tennis matches, William's talk with Hakim as well as William's date with Emma.
Covering chapter 5.
In the anime, Emma is giving some sort of narration about Kelly. In the manga, it's Kelly giving a first person narration about herself and her thoughts on Emma.
The "Mr. and Mrs Knox" plot-line is anime original.
In the anime, Al is called due to a bit of water damage. In the manga, it's because of A LOT of water damage and ongoing infiltration.
In the manga, she calls Al by telephoning to the bar he was at.
In the anime, Kelly asks Emma to offer something to Al in the kitchen. In the manga, Kelly asks all to help putting all the furniture back in their original places.
Since the Knoxes plotline is anime original, Al never dines with Emma and Kelly in the manga.
In the anime, Kelly falls due to coming back to grab a book. In the manga, is because she's moving a basket full of memorabilia to the other floor.
In the anime, Kelly asks Emma to retrieve her necklace. In the manga, she already did that beforehand.
In the manga, it seems that Emma just found Kelly's photo with her husband.
In the anime, Mrs Stownar gives her necklace to Emma, this doesn't happen in the manga.
Covering the other half of chapter 7.
The entire first half of the episode is anime original: William's father talk with Stevens, Emma's talk with Kelly, Jones siblings talking among themselves, William's talk with Hakim, some more lines between William's father and Stevens, the whole scene in "Martin & Sarah" and a Ball that William did not attend, but his father did.
In it, Richard Jones learns of Mrs Stownar's situation from Mrs. Campbell. We are never explicitly told from who he heard it from in the manga.
In the manga, this whole situations happens right after the first Ball from episode 2.
In the anime, there's an extra scene of Emma encouraging the girl that's going to boarding school.
In the anime, we have an added joke of William thanking his father for making him visit Mrs. Stownar.
In the anime, William learned about Mrs. Stownar's condition via Emma. In the manga, it was via the librarian from episode 4 / chapter 6.
In the anime, we have an extra line of Kelly asking Emma to bring scones. In the manga, we have extra lines of William said he only danced with Eleanor out of courtesy.
The scene is extended in the anime.
An Epilogue of Eleanor talking about William with her maid from the manga was cut.
Covering chapter 8.
The manga starts with a "flash-forward" scene of William asking Stevens to close the curtains.
The party at the Campbell's estate is anime original.
In the manga, we learn that Al was taking care of Kelly during Emma's day off. There was a whole dialogue between the two that was cut.
In the manga, we are shown some other architectural styles before going to Egyptian.
The dinosaurs are anime original.
The anime goes into detail about the controversy behind it's construction.
The scene where they are separated from one another is also anime original.
The first half the dialogue between William and Emma while they're stuck inside the Crystal Palace is anime-original.
Hakim talking with Stevens is anime original.
When the palace is finally reopened, in the manga the guard seems very worried about them and we learn that ti is the first time something like that has happened.
The anime has an extended scene with Emma and Kelly.
Covering the remaining of chapter 6 (Literally three pages) as well as the remaining parts of chapter 9.
The start of the episode is extended anime-original scene.
The story about a father falling on the Thames River here is told by a watchmaker in the anime. In the manga, it was told by the librarian from episode 4 / chapter 6.
William's letter to Emma was anime-original.
Some parts of the Jones Siblings dialogue from chapter 9 was cut (Yes, it appeared in three distinct episodes and there was still more), though Collin received some lines.
In the manga, Richard Jones interrupts the siblings squabble (Remember, it's their first appearance in the manga), while in the anime William goes to talk to him directly.
In the anime, Kelly asks for her walking stick to be adjusted. This doesn't happen in the manga.
Richard looking at a painting of his wife is anime original.
With the exception of the doctor scene (Which is expanded) and the scene of Emma going to sleep in the same bedroom, the rest of the episode is anime original.
In the manga, Kelly's death is off-screen.
Covering chapters 10 and 11.
Kelly's funeral, Hakim and William's talk, as well as Eleanor's corset scenes are anime original.
In the manga, Emma says how she still haven't processed Kelly's death. In the anime, Al asks if she already told William.
Emma cleaning the house scene from the manga is extended in the anime.
Some small changes in dialogue during the party.
In the anime, Eleanor asks Grace if there's someone that William likes. That doesn't happen in the manga.
William's scene with a tipsy Eleanor is anime original. In the manga, they see each-other off.
The dialogue inside the carriage was slightly changed.
Eleanor's manga epilogue was cut off... again.
Covering chapter 12.
Hakim and Vivian's scene from the manga is expanded on the anime.
In the manga, Stevens goes to open the gate to Emma directly, there is no gatekeeper.
In the manga, it appears that William and Emma were supposed to meet at the park, but William was late, so Emma went directly into the Jones' estate. In the manga, Emma goes there directly while William is at "Martin & Sarah", where he learns of what happened to Mrs. Stownar.
The siblings have some extra lines in the anime.
The scene with the Campbells is anime original.
The entire rest of the episode is anime original (Emma and William don't meet again in the manga, nor does William's father slap him).
Covering most of chapter 13 and some pages from chapter 14.
The first half of the episode is anime original: Emma talking with Al, the maids gossiping among themselves, William speaking with his father, Emma's stroll, Mrs Campbell speaking with Richard Jones and William leaving his house despite being prohibited by his father.
The scenes about Al's neighborhood, and parts of Emma's past are expanded a bit in the anime.
Covering some remaining pages from chapter 13, the rest of chapter 14 and some pages from chapter 15.
The start of the episode is anime original: Emma's talk with Al, her visiting Kelly's grave, as well as the scene with the Jones siblings.
William's talk with Hakim is expanded in the anime (In the manga there aren't even speech bubbles), however, due to the change of events, Hakim's talk with Stevens was cut.
Eleanor's scene is anime original.
Emma doesn't leave a letter in the manga.
The public transportation scene is different in both versions.
The train station scene is shorter in the anime.
In the manga, William and Emma do not meet.
Feel free to correct or remind me of anything I might have missed in the comments.
Edit: It seems that many of the changes were made because the author admits to only finishing setting up "the status quo" after volume 3, hence why the anime had to "make one of it's own". Also, some small details such as Hakim's room decoration and the Jones manor having a gatekeeper are not anime original, they just come later in the manga.
@SIimyBread
The second season deviates a lot from the manga and has an original ending, so I'm not even sure if that is answerable.
That being said, I've recently began reading that part of the manga, so if I find out there's an answer, I'll tell you.
thewiru said: @SIimyBread
The second season deviates a lot from the manga and has an original ending, so I'm not even sure if that is answerable.
That being said, I've recently began reading that part of the manga, so if I find out there's an answer, I'll tell you.
thanks. I've read 20 chaps of the manga and was thinking if i should watch s2 or just finish the manga
thewiru said: @SIimyBread
The second season deviates a lot from the manga and has an original ending, so I'm not even sure if that is answerable.
That being said, I've recently began reading that part of the manga, so if I find out there's an answer, I'll tell you.
thanks. I've read 20 chaps of the manga and was thinking if i should watch s2 or just finish the manga
Do both. After watching the anime, read the whole manga. The manga is much longer than the anime, and as a fellow poster said, the anime has an original ending, whereas the manga keeps going much longer.
thewiru said: @SIimyBread
The second season deviates a lot from the manga and has an original ending, so I'm not even sure if that is answerable.
That being said, I've recently began reading that part of the manga, so if I find out there's an answer, I'll tell you.
thanks. I've read 20 chaps of the manga and was thinking if i should watch s2 or just finish the manga
Do both. After watching the anime, read the whole manga. The manga is much longer than the anime, and as a fellow poster said, the anime has an original ending, whereas the manga keeps going much longer.
Both are great, and you won’t regret it 🤗
I'm loving the manga. one of the most beautiful mangas I've read. I'll watch the anime after finishing manga
@SIimyBread
Well, having finished the manga, I have your answer: Most of season 2 is original, save for one thing or another.
Note that the manga technically has "two endings": One at the end of volume 7, then volumes 8, 9 and 10 are of "side-stories", however the side stories of volume 10 include what happens to our two protagonists after the ending of volume 7.
What I can say is that, without knowing that beforehand, the "ending" on volume 7 feels somewhat "abrupt" or "sudden", and in that regard I appreciate season 2 of the anime for actually taking it's time with it's original ending and making it the culmination of an entire arc.
There are certain things I think the manga did better and things I think the anime did better, so treat the two as "complimentary works".