I know that in the manga it states she is over 900 years old, but how old is Chibiusa (appearance wise) in R, S, and SuperS? I've kinda been wondering what other people thought about that (and I don't believe this question has been asked before).

To me it seems like:

In R: she's about five or six.

In S: she's about 10.

In SuperS: she's about 12-13.

I feel like each time Chibiusa returns to the 20th century she's a bit older than the last time she appeared. And she looks substantially older in SuperS. Especially in the SuperS movie when Sailor Moon revives her (there's a scene that shows she's "developing" for a lack of a better way to say that). Plus I figure, since SuperS focuses on her and her relationship with Helios, Chibiusa has to be of an age where actual romantic feelings can develop for another person, not just a little innocent crush.

Thoughts? ^^ (also sorry if this is a lame topic XD)

I think since Chibiusa in the twenty-first century she can grow older because she not in Crystal Tokyo.That`s my guess

I noticed in the move "Black dream hole" that she a bit taller.

It's hard to discuss her age in the anime. Seeing how Classic and R happened in the same year (school wise) and S and SuperS likewise. Then there's Stars where the girls finally become high schoolers. I'm amusing when Chibiusa goes home time flows differently seeing how they're so far in the future. So I guess she would age quicker.

What I think:
R: 6 or 7 years old. She seems rather smart for 5 a year old.
S: 8 or 9.
SuperS: 10 seeing how she doesn't go home after S ended. I feel like she's too short to be a 12 or 13 old. Then again I'm really short for a 22 year old girl.

I've always thought of this as well, so I thought of some theories.

When Chibiusa first went to the 20th century, she was obviously 5-6 since she was in kindergarten. Now I clearly remember that all through the series, she doesn't go to junior high at all, so she can't be any older than 12.

I believe in S, when she returns to the 20th century for senshi training, she had aged to about 8-9, due to her senshi awaking powers, which would make her 10 at the beginning of SuperS. After gaining her Super Senshi powers from Pegasus, that probably aged her as well, which would make her 11-12.

This is all of course theory, and it doesn't change the fact that she is 900 in Crystal Tokyo years. haha

I know this is old but in Materials collection, Naoko-sama said that in R/Black Moon arc Chibiusa looks like a first-grader so about 6-7 years old (I'd say more like 6), in S/Mugen arc, she's an older elementary school girl (I'd say about . The rest are unconfirmed but I'm leaning towards 10 years old in SS/Dream Arc and 11-12 in Stars when she returned for a bit (If she returned after the Stars arc next year I'd say she would be 12 and prepare for her exams for graduating elementary school and joining Junior High)

In the original anime series she always look younger than her manga version, even though she grows up in both. To me, she is 6-7 on the start and looks about 10-11 at the end.

BUT something kinda bothers me... She starts as a first-grader and ends as a third-grader (As seen in the Stars short story) so she should be 8-9 at the end, actually? But she looks older. Hotaru looks like a third-grader, but not Chibiusa. To be really honest... Naoko draws little girls as teenagers, sometimes. Momo, Chibiusa´s best friend, is a notable example.

According to the anime, Usagi starts off at 14 and when Stars ends, she says she's 16. Two years between everything, so I'm guessing Chibiusa is 8 in R and is 10 towards the end.

In the manga/Crystal, it is mentions mentally she's about 900 years old.  However, physcially speaking she's probably about 10/11.  She hadn't "awakened" yet as a sailor soldier so stayed as child in physical form.