What is the ‘right’ scale for child dolls next to SD dolls?

Their appearance may not be young-looking enough for what you were aiming for, but my main characters' younger children are shelled out as Iplehouse JIDs (43-46cm). When with their dad (a Granado Noah on the 75Adagio body), they're very to-scale. This is him carrying my IH Violet.


Wishing Lights by Yela Gatchalian-David, on Flickr

This photo probably shows the scale better, as both Noah and my JID Edwin were on their feet during the shoot. Here they are with their 65cm mother and older sister (and grumpy 72cm older brother). Childlike MSDs aren't my favored size so I do not have much experience with it. But apart from the height, I take into account the head circumference and over-all aesthetic. Iplehouse JID heads are large compared to, say, Dream Valley and Doll Chateau, whose more stylized bodies would stand out if the bigger dolls are more realistically proportioned.

 

Quick and dirty photo – please excuse living room clutter, tried to find a room with natural light.
RS Doll 68cm boy with 2 minis: Volks SDM girl on left, 42cm; and Volks SDC boy on right, 44cm. The SDM body is a younger look than the SDC.

 

I don't have any set children characters at the moment (as a caveat).

My friend's daughter when she was 3 years old was hip height, so height can really vary I would check heights of actual 5 year olds who are similar to your character and see how they look with with adults and then work out the height you need with the bjds you have? I have in the past made a cardboard cut out to work out sizing of potential bids with my crew. I find this works immensely as it is something tangible to work with when looking.

Have a look at Dollstown... they have a range of ages which could help you work out proportions and heights.

 

I think the best aproach it to make a distinction between size and scale.
If you think abut it, if you scale down two people of different height, their relative size compared to each other it going to stay the same.

Here is the math method:
You can start by figuring out what real life size your current dolls are supposed to represent. When knowing that you can figure out what scale they are.
Then you can look at charts on line for what the average height is for a child the age you want to represent. Divide the height of the child by the scale you came up with and that's how tall the child doll need to be.
(Example: If your doll is scaled 1:3 and the average height for a child in the age you want is 120cm you'll get 120/3=40. So 40cm tall in doll form.)

Pay attention to head size and eye size. Dolls are often stylized and their proportions are not always realistic. To get a doll that look in style as well as in scale with another, you want to make sure that the childs head isn't too much smaller than the adults. Heads are proportionally larger on small children compared to adults in humans and reach full adult size long before the body does. Because of this it's usually safe to go with a child doll with a head just slightly smaller than the adult, especcially if the child is an older child. Same thing about eyes.

 

In addition to the height/scale, you'll also want to look at body aesthetics/measurements. A slim mini like resinsoul or minifee will look very out of scale with a 1/3 size doll because they are made to look like scaled-down adults - you'll want to look into chubby/childlike/"big baby" 1/4 dolls. Myou has a line like that, SpiritDoll has the Healing(BB) line, Maskcat 1/4s, Volks MSDs or DearSDs, Island Doll Wind line, Guard Love with certain bodies could work for that, too. Huajing's older mini bodies are more childlike as well and many of their heads look very young but they might be too small in scale.

 

At one point this bugged me a lot but it was very difficult to find a sculpt I both liked and was in the correct size/scale next to my bigger dolls so I prioritised dolls I liked over the precise scale. It will depend a lot on what size your bigger dolls are.
In my case my biggest dolls are 70 and 65cm tall. My youngest dolls are 35cm. I play the young ones as being between 7-9 year olds. It doesn't work if you do the math with the scale but I reeeeally like the 35cm range dolls, it's like the perfect size for me, so I sacrificed the accuracy for dolls I liked. It's totally true that there isn't many dolls in that scale sadly and I'm always hoping more are created.

In my case if I wanted it very accurate what I would do is decide what height my doll of reference would have in real life to calculate how big the child doll has be to look the age proportionate to the scale, so for example, let's say that I have a doll that is 70cm tall, in my mind this doll is 180cm tall if they were human. I want a child that looks about 5 years old next to them, and the average 5 year old boy is around 110cm tall. Then I just apply a cross multiplication.
If 180cm is 70cm in doll form, how much would it be 110cm in doll form?
180 -----70
110 ----- X
Multiply 110x70 and divide the result by 180 and that gives you 42.77cm. So if you want a doll that looks in scale next to your 70cm doll for a 5 years old you need a doll around that height.

As mentioned before by kyukyukyu children's heights can also vary a lot, but either way you can decide once you have the number to get something a bit smaller or bigger to suit your preference.

This would work if dolls had stayed at the standard they were when they started, Volks did a good job at the scale part when it comes to this, sadly nowadays with so many different sizes of dolls, and especially bigger dolls it doesn't work. Yosd sizes look way too small for 70cm dolls unless they're babies (it's the reason I got rid of my yosd sized dolls because also their faces are not baby enough either). Either way, if I take my own height of 167cm to 1/3 it means I need a doll that it's around 55cm to represent me what might limit my creativeness or pool of available sculpts. Funny enough those are considered nowadays like mini SD sized dolls and I don't think I'm very short. On the other hand if I want to know how tall a 70cm doll would be in real life you get a result of 210cm, they're huge! I don't even know anyone that tall in real life around me (and my brother is 195cm).
So personally I think it's better and easier to decide what you want that 70cm doll's height (or whichever doll you take as your base for the scale of your doll family) to be in real life and scale everything else appropriately.
But it's very true that it's difficult to find dolls that are the size you need that have features you need in their represented age. Getting a more child-like 43cm doll might be difficult although I do know of a few, but obviously it does limit you as well in that sense. It will depend on if the height or the proportions are more important to you and how far you want to go in terms of realisticness.

That's how I do it anyway, I'm not a math expert and when it comes to scales and what people prefer is obviously very subjective.

 

This is a challenge that I had when I was looking to have "SD" size doll family. I think the article by Requiem Art Design on scale is a really good read. Materials Monday: Scale in dolls and doll clothing Highly recommend as they are much more detailed and succinct than I am.

What I ended up doing was going with Dollstown for my children dolls. Here is an old photo of them. The parents are on different bodies now, but are roughly the same height.



You can also look at the CDC growth chart as a guide for US heights. The median height for a 5 year old boy is 109cm. If your dolls are 1/3 scale, then divide by 3.

At this point, I've decided that my dolls are 1:2.75 scale since most people are just not as tall as doll makers make them, so the kids heights line up with the median height for ages 7 and 11 here. This still makes the parents in the 90-100 percentile in height... but doll makers are not going for the median population.

 

This is why the first step I mentioned is so important. Maybe I could have expressed it more clearly, english is not my first language.
(Ignore the "scale" given by companies, that is an oversimplification that is mostly there to roughly sort dolls into general size categories and have little to do with actual scale.)

This is how you do it, anyway:
1. Take the height of the adult you want to represent and divide it by the height of the doll you want to use. This gives the actual scale.
Example: Adult 175cm tall represented by a doll 60cm tall. 175/60=2,91666 etc. Let's call it 2,9. So the scale in this case is 1:2,9.
2. Take the desiered height of the child to represent and divide this by the number you just got.
Example: Child 120cm tall. 120/2,9=41,3 (and some additional decimals). So the doll you would need to represent this child at this scale would be just over 41 cm tall.

This only deals with height though, not proportion.

When looking at humans in art, proportional height is often discussed in number of head heights that a figure is tall.
The head grows at a slower rate than the rest of the body and so the head will be proportionally larger in a small child than in an adult, while still being smaller in actual measurements. This is often the key to getting a good match.
A new born human is about 4 head heights, meaning that about a forth of their height consists of head. Adults vary a lot, but somewhere in the range of 7-9 head heights is quite normal.

Intentionaly stylized proportions makes use of this all the time to convey a certain message, function or look. A chibi may be only two heads tall to convey cuteness and give a lage focus on facial expression, while a fashion plate can have a figure 12 or more heads high to give an extreeme enlongated look and keep the face from drawing attention away from the clothes.
Similar trends are common with dolls and should be taken into consideration. When looking for dolls that goes well together it usually good to aim at dolls that have similar choices made when it comes to proportions.

 

As has been mentioned, I found it important to consider facial sculpts & head sizes when choosing my "kids".
My SDs were old school Soom & Elfdoll so the features of Volks msds & yos weren't what I wanted. And in the other direction the Iplehouse sculpts weren't right either. Dollshe had their two children dolls which I adore the look of but the sculpt style wasn't quite right & availability nixed that possibility. And while I adore all the various DollsTown sculpts with various kid size bodies they need adults with similar proportions to work for me...

In the end my Macchonna kids include a Migidoll head on a Volks body (almost 60cm) as a teen, an LLT SD head on a DollsTown elf body as a young teen, Dollmore Alexia about 9, Luts Kid Delf Muhwa about 7 [many kid Delf sculpt choices available & that size might work for a 5 yr old for taller SD parents], Dollmore Narsha who is my 4-5 yr old & her stocky body to me is a perfect kid representation, then a Custom House Petite Ai which is 31cm is my toddler. So even the smallest is still a surprising 11" tall when I measure her!?! In fact there are a couple of tinies on my wishlist who look cute as can be but are just too small to be a practical step in the family, or to look right with the SD dolls.

Besides height the biggest concern to me was that there be a family resemblance & sculpts that work well together. It was a fun excuse to look at lots of company photos & second hand sale listings
If you search my photo posts the Macchonna family are often there.

As another old school family, I have Luts CPDelf dolls with Fairyland littlefee children. The SD adults are on the shorter side at 57-60cm but the kids are definitely toddlers as they are about 30cm & look small with the adults.

It's definitely tricky. And I was surprised just how big a doll looked small when set with the SD dolls. Good luck finding a sculpt & size you like, when you find them it's worth the trouble.

 

Sorry, totally my bad, when I read your message I thought you meant generally doing the math with the scale they're, as in, for example most 60cm+ dolls are considered 1/3 scale even if they're not. Basically I thought you meant classifying the scale of your doll based on the known average scales used for BJD categorisation. Sorry for the confusion.
And totally agree with the proportion parts like I said in my first post and I think it's the most difficult part to find very good matches scale wise.

 

No worries, I could have put it more clearly.