TL;DR
Size children's styles by measurement bands rather than age, confirm trims and labelling expectations in writing, and test dressing access on a real child before you approve the range.
Age bands are not size bands
Parents shop by age, but garments are built to measurements. A two-year-old and a four-year-old can share a height band while differing in chest and torso length, so a range labelled only by age will fit unevenly. Publish both an age guide and a measurement chart, and make clear which one the pattern was graded from.
For toddler Halloween costumes and baby Halloween costumes, height and torso length matter more than chest width, because a one-piece style either clears the shoulders or it does not. Ask the supplier for the finished garment length per size, then compare that with the height band you intend to publish.
Safety and labelling questions belong in the RFQ
Children's products carry obligations that adult styles do not, and the applicable rules depend on the destination market. Rather than assuming compliance, put the question into the RFQ: which tests or declarations does the supplier already hold for this fabric and these trims, and what documentation can be shared with your order.
The U.S. Consumer Product Safety Commission publishes guidance on clothing and on children's product certification. Use those resources to frame the questions you send and to decide what evidence your business needs before listing, and record the answers you receive. A short written answer is easier to rely on than a verbal assurance.
Dressing access decides whether it gets worn
A baby costume is changed in the middle of a party, so access matters as much as appearance. Look for snaps or a zip at the inseam, a front opening that does not require removing the whole garment, and a neckline that clears the head without pulling on ears.
Check the trims as well: long ties, loose cords, detachable parts and hard decorations close to the face are the first things to question. Ask for a sample in the smallest size and dress a real child in it, then note how long it takes and what had to be adjusted.
Girls and boys lines overlap more than catalogues suggest
Many girls Halloween costumes and boys Halloween costumes share the same body block with different colourways or trims. That is efficient, but it means a style sold in both lines may fit differently from a dedicated pattern. Ask which styles use a shared block and confirm the measurement chart applies to both versions.
Where a style is cut for one group only, say so in the listing. Buyers comparing kids costumes across suppliers benefit from knowing whether a design is a genuine separate pattern or a variation of an existing one.
Group and school orders need a labelling plan
Class, dance group and family orders arrive as many small requests that behave like one bulk order. The garment work is standard, but picking and labelling are not, so agree the format before production: individual polybags with a name field, a size breakdown per carton, or a printed pick list.
- Size breakdown confirmed per style before cutting
- Individual bag with a name or number field
- Carton label matching the pick list
- Spare fasteners packed with each bag
- One sample per size group retained by both sides
What to confirm before you sign off
Confirm the measurement chart, the age guide, the trim list and the labelling questions in writing, then keep the approved sample with its record. A children's range is judged on the second wear as much as the first, and the record is what lets you correct a repeat order instead of starting the discussion again.