If your part number starts with GC:
ITEM SIZE HEIGHT WEIGHT WAIST HIPS CHEST INSEAM
Baby Bunting
3 months
6 months
9 months
20-23"
23-25"
25-28"
7-10 lbs
10-14 lbs
14-18 lbs
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-
-
-
-
-
-
-
-
-
-
-
Baby Costumes
6 to 12 Months
12- 24 Months
28 3/4"
30"
-
-
20"
19.5-20.5"
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-
-
-
-
-
Toddler 2-4T
2
3
4
26-29"
29-32"
33-36"
-
-
-
21"
22"
23"
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-
-
-
-
-
-
-
-
Children 4-6x
4
5
6
33-36"
37-40"
41-48"
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-
-
24"
25"
26"
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-
-
-
-
-
-
-
-
Children 7-10
7 Small
8 Medium
10 Large
49-53"
53-55"
55-57"
-
-
-
22.5"
24"
25"
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-
-
-
-
-
-
-
-
Teens 12-16
12
14
16
55.5-57.5"
58-60"
-
27"
28"
29"
-
-
-
-
-
-
33"
34"
35"
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-
-
Women
4 Small
6 Medium
8 Medium
10 Medium
12 Large
-
-
-
-
-
-
-
-
-
-
26"
27"
28"
29.5"
31"
37"
38.5"
39.5"
40.5"
42"
34"
35"
36"
37.5"
39"
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-
-
-
-
Women Plus
14
16
18
20
-
-
-
-
-
-
-
-
33"
34.5"
36"
37.5"
45"
46"
48"
51"
41"
42.5"
44"
45.5"
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-
-
-
Men
Medium
Large
X-Large
up to 5'7"
5'8"-6'
6'-6'3"
-
-
-
32-34"
36-38"
35-36"
-
-
-
38-40"
42-44"
46-48"
-
33"
-
Men Plus
XX-Large/Plus
6'3"+
-
36-37"
-
50-52"
35"
One Size
Children - fits most sizes 7-10
Women - fits most sizes 6-10
Men - fits most sizes large to extra-large

PET Costumes:
XSmall: 8"-10" from neck to tail base.
( Toy Poodle, Maltese, Shih Tzu)
Small: 11"-14" from neck to tail base.
( Cats, Yorkies, Pugs, Jack RuSell)
Medium: 15"-22" from neck to tail base,
( Beagles, Cocker Spaniels, Shelties)
Large: 22"-28 from neck to tail base,
( Labs, Boxers, Dobermans)
X Large: 28"+ from neck to tail base

Universal Women's Dress Size Conversion Chart
This is only a guide if the manufacture lists measurements in inches use that.

U.S. U.S. (letter sizes) U.K. France

Select the size in your country and note the US sizing.
Germany Italy Australia Japan