theory Size Chart
Use this theory Size Chart to compare clothing and shoe sizes before placing your order. Body measurements are shown in inches unless noted. For the most accurate fit, compare your measurements with the chart and check the product details for any item-specific fit notes.
Outerwear & Jackets
| Measurement | 00 | 0 | 2 | 4 | 6 | 8 | 10 | 12 |
|---|---|---|---|---|---|---|---|---|
| UK Size | 2 | 4 | 6 | 8 | 10 | 12 | 14 | 16 |
| Alpha Size | XS | XS | S | S | M | M | L | L |
| Bust | 30–31" | 31–32" | 32–33" | 33–34" | 34–35" | 35–36" | 36–37" | 37–38" |
| Waist | 24–25" | 25–26" | 26–27" | 27–28" | 28–29" | 29–30" | 30–31" | 31–32" |
| Hip | 33.5–34.5" | 34.5–35.5" | 35.5–36.5" | 36.5–37.5" | 37.5–38.5" | 38.5–39.5" | 39.5–40.5" | 40.5–41.5" |
| Arm | 31.5–32" | 31.5–32" | 32–32.5" | 32–32.5" | 32.5–33" | 32.5–33" | 33–33.5" | 33–33.5" |
Dresses
| Measurement | 00 | 0 | 2 | 4 | 6 | 8 | 10 | 12 |
|---|---|---|---|---|---|---|---|---|
| UK Size | 2 | 4 | 6 | 8 | 10 | 12 | 14 | 16 |
| Alpha Size | XS | XS | S | S | M | M | L | L |
| Bust | 30–31" | 31–32" | 32–33" | 33–34" | 34–35" | 35–36" | 36–37" | 37–38" |
| Waist | 24–25" | 25–26" | 26–27" | 27–28" | 28–29" | 29–30" | 30–31" | 31–32" |
| Hip | 33.5–34.5" | 34.5–35.5" | 35.5–36.5" | 36.5–37.5" | 37.5–38.5" | 38.5–39.5" | 39.5–40.5" | 40.5–41.5" |
| Arm | 31.5–32" | 31.5–32" | 32–32.5" | 32–32.5" | 32.5–33" | 32.5–33" | 33–33.5" | 33–33.5" |
Bottoms
| Measurement | 00 | 0 | 2 | 4 | 6 | 8 | 10 | 12 |
|---|---|---|---|---|---|---|---|---|
| UK Size | 2 | 4 | 6 | 8 | 10 | 12 | 14 | 16 |
| Waist | 24–25" | 25–26" | 26–27" | 27–28" | 28–29" | 29–30" | 30–31" | 31–32" |
| Hip | 33.5–34.5" | 34.5–35.5" | 35.5–36.5" | 36.5–37.5" | 37.5–38.5" | 38.5–39.5" | 39.5–40.5" | 40.5–41.5" |
| Inseam Short | 27–29" | 27–29" | 27–29" | 27–29" | 27–29" | 27–29" | 27–29" | 27–29" |
| Inseam Regular | 30–33" | 30–33" | 30–33" | 30–33" | 30–33" | 30–33" | 30–33" | 30–33" |
| Inseam Full | 34–35" | 34–35" | 34–35" | 34–35" | 34–35" | 34–35" | 34–35" | 34–35" |
Tops
| Measurement | XS | S | M | L |
|---|---|---|---|---|
| US Numeric | 00–0 | 2–4 | 6–8 | 10–12 |
| UK Numeric | 4–6 | 8–10 | 10–12 | 14–16 |
| Bust | 30–32" | 32–34" | 34–36" | 36–38" |
| Waist | 24–26" | 26–28" | 28–30" | 30–32" |
| Arm | 31.5–32" | 32–32.5" | 32.5–33" | 33–33.5" |
Shoes
| US Size | UK Size | EU | Japan |
|---|---|---|---|
| 5 | 2.5 | 35 | 21.5 |
| 5.5 | 3 | 35.5 | 22 |
| 6 | 3.5 | 36 | 22.5 |
| 6.5 | 4 | 36.5 | 23 |
| 7 | 4.5 | 37 | 23.5 |
| 7.5 | 5 | 37.5 | 24 |
| 8 | 5.5 | 38 | 24.5 |
| 8.5 | 6 | 38.5 | 25 |
| 9 | 6.5 | 39 | 25.5 |
| 9.5 | 7 | 39.5 | 26 |
| 10 | 7.5 | 40 | 26.5 |
| 10.5 | 8 | 40.5 | 27 |
| 11 | 8.5 | 41 | 27.5 |
| 11.5 | 9 | 41.5 | 28 |
| 12 | 9.5 | 42 | 28.5 |
How to Choose Your Size
- Start with the category that matches the item you are buying, such as outerwear, dresses, bottoms, tops, or shoes.
- Compare your body measurements to the chart instead of choosing only by your usual size.
- For structured pieces such as jackets, blazers, and tailored dresses, check bust, waist, hip, and arm measurements where applicable.
- For bottoms, compare both waist and hip measurements, then review inseam length if the product offers different lengths.
- For shoes, compare your usual US size with the UK, EU, and Japan size conversions shown in the table.
Measuring Tips
- Bust: Measure around the fullest part of your bust while keeping the tape level.
- Waist: Measure around your natural waist, keeping the tape comfortably close to the body.
- Hip: Measure around the fullest part of your hips.
- Arm: Measure from the center back of the neck across the shoulder and down the arm.
- Inseam: Measure from the top of the inner leg down to the preferred hem length.
Fit Notes
Size charts are a general guide, and fit can vary by fabric, cut, stretch, silhouette, and intended styling. A tailored jacket may feel closer to the body, while a relaxed top or coat may be designed with more room.
Always review the product page for item-specific fit details, model information, fabric notes, and any sizing recommendations before ordering.
Between Sizes
If your measurements fall between two sizes, choose the smaller size for a closer fit or the larger size for more ease. For fitted dresses, tailored jackets, and slim bottoms, the larger size may feel more comfortable if you prefer extra room through the bust, waist, hips, or shoulders.
Product Detail Reminder
Some products may have a unique fit, length, or fabric structure. Please check the individual product description and available size notes before adding an item to your cart.
Customer Support
Need help choosing a size? Contact theory customer support at [email protected]. Please include the product name, your usual size, and the measurements you would like help comparing.
