Brand fit guide

Theory

Runs small

Modern suiting, runs slim with tailored proportions.

How Theory fits

Tops

Runs small

Slim tailored cut. Size up 1 if between sizes.

Bottoms

Runs small

Slim through thigh. Size up 1 for comfort.

Outerwear

Runs small

Tailored slim. Size up 1 for layering.

Theory size chart

bottoms

bottoms · Body measurements in inches

Theory bottoms size chart for US
Size	Bust (in)	Waist (in)	Hips (in)
0	31 to 32	23 to 24	33 to 34
0	Not listed	25 to 26	34.5 to 35.5
00	Not listed	24 to 25	33.5 to 34.5
2	32 to 33	24 to 25	34 to 35
2	Not listed	26 to 27	35.5 to 36.5
4	33 to 34	25 to 26	35 to 36
4	Not listed	27 to 28	36.5 to 37.5
6	Not listed	28 to 29	37.5 to 38.5
6	35 to 36	27 to 28	37 to 38
8	Not listed	29 to 30	38.5 to 39.5
8	36 to 37	28 to 29	38 to 39
10	37 to 38	29 to 30	39 to 40
10	Not listed	30 to 31	39.5 to 40.5
12	Not listed	31 to 32	40.5 to 41.5
12	39 to 40	31 to 32	41 to 42
14	41 to 42	33 to 34	43 to 44
16	43 to 44	35 to 36	45 to 46

Theory bottoms size chart for US
Size (US)	0	0	00	2	2	4	4	6	6	8	8	10	10	12	12	14	16
Bust (in)	31 to 32	Not listed	Not listed	32 to 33	Not listed	33 to 34	Not listed	Not listed	35 to 36	Not listed	36 to 37	37 to 38	Not listed	Not listed	39 to 40	41 to 42	43 to 44
Waist (in)	23 to 24	25 to 26	24 to 25	24 to 25	26 to 27	25 to 26	27 to 28	28 to 29	27 to 28	29 to 30	28 to 29	29 to 30	30 to 31	31 to 32	31 to 32	33 to 34	35 to 36
Hips (in)	33 to 34	34.5 to 35.5	33.5 to 34.5	34 to 35	35.5 to 36.5	35 to 36	36.5 to 37.5	37.5 to 38.5	37 to 38	38.5 to 39.5	38 to 39	39 to 40	39.5 to 40.5	40.5 to 41.5	41 to 42	43 to 44	45 to 46

dresses

dresses · Body measurements in inches

Theory dresses size chart for US
Size	Bust (in)	Waist (in)	Hips (in)
0	31 to 32	25 to 26	34.5 to 35.5
00	30 to 31	24 to 25	33.5 to 34.5
2	32 to 33	26 to 27	35.5 to 36.5
4	33 to 34	27 to 28	36.5 to 37.5
6	34 to 35	28 to 29	37.5 to 38.5
8	35 to 36	29 to 30	38.5 to 39.5
10	36 to 37	30 to 31	39.5 to 40.5
12	37 to 38	31 to 32	40.5 to 41.5

Theory dresses size chart for US
Size (US)	0	00	2	4	6	8	10	12
Bust (in)	31 to 32	30 to 31	32 to 33	33 to 34	34 to 35	35 to 36	36 to 37	37 to 38
Waist (in)	25 to 26	24 to 25	26 to 27	27 to 28	28 to 29	29 to 30	30 to 31	31 to 32
Hips (in)	34.5 to 35.5	33.5 to 34.5	35.5 to 36.5	36.5 to 37.5	37.5 to 38.5	38.5 to 39.5	39.5 to 40.5	40.5 to 41.5

outerwear

outerwear · Body measurements in inches

Theory outerwear size chart for US
Size	Bust (in)	Waist (in)	Hips (in)
0	31 to 32	25 to 26	34.5 to 35.5
00	30 to 31	24 to 25	33.5 to 34.5
2	32 to 33	26 to 27	35.5 to 36.5
4	33 to 34	27 to 28	36.5 to 37.5
6	34 to 35	28 to 29	37.5 to 38.5
8	35 to 36	29 to 30	38.5 to 39.5
10	36 to 37	30 to 31	39.5 to 40.5
12	37 to 38	31 to 32	40.5 to 41.5

Theory outerwear size chart for US
Size (US)	0	00	2	4	6	8	10	12
Bust (in)	31 to 32	30 to 31	32 to 33	33 to 34	34 to 35	35 to 36	36 to 37	37 to 38
Waist (in)	25 to 26	24 to 25	26 to 27	27 to 28	28 to 29	29 to 30	30 to 31	31 to 32
Hips (in)	34.5 to 35.5	33.5 to 34.5	35.5 to 36.5	36.5 to 37.5	37.5 to 38.5	38.5 to 39.5	39.5 to 40.5	40.5 to 41.5

tops

tops · Body measurements in inches

Theory tops size chart for US
Size	Bust (in)	Waist (in)	Hips (in)
XS	31 to 33	24 to 26	34 to 36
XS	30 to 32	24 to 26	Not listed
S	33 to 35	26 to 28	36 to 38
S	32 to 34	26 to 28	Not listed
M	35 to 37	28 to 30	38 to 40
M	34 to 36	28 to 30	Not listed
L	37 to 39	30 to 32	40 to 42
L	36 to 38	30 to 32	Not listed
XL	39 to 41	32 to 34	42 to 44

Theory tops size chart for US
Size (US)	XS	XS	S	S	M	M	L	L	XL
Bust (in)	31 to 33	30 to 32	33 to 35	32 to 34	35 to 37	34 to 36	37 to 39	36 to 38	39 to 41
Waist (in)	24 to 26	24 to 26	26 to 28	26 to 28	28 to 30	28 to 30	30 to 32	30 to 32	32 to 34
Hips (in)	34 to 36	Not listed	36 to 38	Not listed	38 to 40	Not listed	40 to 42	Not listed	42 to 44

Theory sizing FAQ

Does Theory Run Small?

Theory is runs small. Modern suiting, runs slim with tailored proportions.

What size should I get at Theory?

Theory bottoms size 0 covers a 23 to 24 inch waist. Match the category and your body measurement to the chart before choosing a label.

Does Theory fit differently by category?

Tops: Slim tailored cut. Size up 1 if between sizes. Bottoms: Slim through thigh. Size up 1 for comfort. Outerwear: Tailored slim. Size up 1 for layering.

Which Theory size chart is available here?

The verified chart covers bottoms and dresses and outerwear and tops. Categories without a stored measurement chart are not shown.

Help improve this guide

How does Theory fit you?

Our confidence is medium. Your experience helps us check the current verdict.

Category (optional)

What did you try? (optional)