Underwear sizes can be converted approximately between women's US, UK, EU, alpha sizing, inches, and centimeters. The converted label is only a starting point because waist, hips, rise, coverage, stretch, support, and brand grading vary.
Direct answer
General underwear size conversion chart
| Women's US | Women's UK | Women's EU | General alpha |
|---|---|---|---|
| 0 to 2 | 4 to 6 | 30 to 32 | XS |
| 4 to 6 | 8 to 10 | 34 to 36 | S |
| 8 to 10 | 12 to 14 | 38 to 40 | M |
| 12 to 14 | 16 to 18 | 42 to 44 | L |
| 16 to 18 | 20 to 22 | 46 to 48 | XL |
| 20 to 22 | 24 to 26 | 50 to 52 | 2XL |
| 24 to 26 | 28 to 30 | 54 to 56 | 3XL |
| 28 to 30 | 32 to 34 | 58 to 60 | 4XL |
Conversion visual
Convert the Label, Then Verify Waist, Hips, and Style
A general medium may correspond to women's US 8 to 10, UK 12 to 14, and EU 38 to 40, but the product chart remains the final guide.
How Underwear Size Conversion Works
Women's US, UK, and EU sizes use different numerical sequences.
Alpha labels group several numerical sizes together, which makes the conversion less precise.
Numerical conversion
Maps regional labels
It identifies a nearby US, UK, or EU size range.
Alpha conversion
Groups several sizes
XS through 4XL can cover different ranges across brands.
Measurement check
Confirms practical fit
Waist, hips, rise, stretch, and coverage remain essential.
Women's Underwear Conversion by Alpha Size
| Alpha | Women's US | Women's UK | Women's EU |
|---|---|---|---|
| XS | 0 to 2 | 4 to 6 | 30 to 32 |
| S | 4 to 6 | 8 to 10 | 34 to 36 |
| M | 8 to 10 | 12 to 14 | 38 to 40 |
| L | 12 to 14 | 16 to 18 | 42 to 44 |
| XL | 16 to 18 | 20 to 22 | 46 to 48 |
| 2XL | 20 to 22 | 24 to 26 | 50 to 52 |
| 3XL | 24 to 26 | 28 to 30 | 54 to 56 |
| 4XL | 28 to 30 | 32 to 34 | 58 to 60 |
Women's Waist and Hip Conversion
| Alpha size | Waist in inches | Hips in inches |
|---|---|---|
| XS | 24 to 26 | 34 to 36 |
| S | 26 to 29 | 36 to 39 |
| M | 29 to 32 | 39 to 42 |
| L | 32 to 36 | 42 to 46 |
| XL | 36 to 40 | 46 to 50 |
| 2XL | 40 to 44 | 50 to 54 |
| 3XL | 44 to 48 | 54 to 58 |
| 4XL | 48 to 52 | 58 to 62 |
Men's Underwear Waist Conversion
| Alpha size | Waist in inches | Approximate centimeters |
|---|---|---|
| XS | 24 to 28 | 61 to 71 cm |
| S | 28 to 31 | 71 to 79 cm |
| M | 31 to 34 | 79 to 86 cm |
| L | 34 to 38 | 86 to 97 cm |
| XL | 38 to 42 | 97 to 107 cm |
| 2XL | 42 to 46 | 107 to 117 cm |
| 3XL | 46 to 50 | 117 to 127 cm |
| 4XL | 50 to 54 | 127 to 137 cm |
Inches-to-Centimeters Waist Conversion
| Inches | Approximate centimeters |
|---|---|
| 24 in | 61 cm |
| 26 in | 66 cm |
| 28 in | 71 cm |
| 30 in | 76 cm |
| 32 in | 81 cm |
| 34 in | 86 cm |
| 36 in | 91 cm |
| 38 in | 97 cm |
| 40 in | 102 cm |
| 42 in | 107 cm |
Why Alpha Sizes Do Not Convert Precisely
Small, medium, large, and extended sizes cover different waist and hip ranges across brands.
One medium may fit closer, higher, or with more compression than another.
Why Converted Underwear Can Fit Differently
- Waistband position differs.
- Waist and hip grading differs.
- Seat coverage differs.
- Gusset or pouch construction differs.
- Leg-opening shape differs.
- Fabric stretch and recovery differ.
- Compression levels differ.
- Brand sizing uses different fit models.
Converting Women's Brief Sizes
Check waist, hips, seat coverage, rise, and leg openings after converting the label.
Converting Bikini and Hipster Sizes
Confirm the lower waistband position and whether the side and leg openings remain comfortable.
Converting Boyshort Sizes
Check hip, seat, upper-thigh, and leg-opening dimensions.
Converting Men's Brief Sizes
Verify waist, pouch, seat, and leg openings rather than relying only on the alpha label.
Converting Boxer-Brief Sizes
Check waist, pouch, seat, thighs, leg length, and whether the hems ride.
Converting Boxer Sizes
Check waistband stability and whether the seat and thighs provide the intended relaxed fit.
Converting Shapewear Sizes
Use the manufacturer's chart because compression levels and garment zones differ substantially.
Do not size down to create more compression.
How to Confirm a Converted Underwear Size
- Identify the original sizing system.
- Convert the numerical or alpha label.
- Compare the waist measurement.
- Compare hips and seat.
- Check waistband rise.
- Check coverage and garment category.
- Review stretch and recovery.
- Check gusset, pouch, and leg openings.
- Use the exact product chart.
Common Underwear-Conversion Mistakes
- Converting the label without checking measurements
- Assuming every medium is equivalent
- Ignoring waist and hip differences
- Ignoring waistband position
- Ignoring coverage and leg openings
- Ignoring compression and fabric recovery
- Expecting regional equivalents to fit identically
- Using a general chart instead of the product chart
Underwear sizing tool
Use the Underwear Size Calculator
Enter waist, hips, height, underwear category, rise, preferred fit, fabric stretch, support level, and displayed sizing system.
Questions and answers
Frequently Asked Questions
What is a women's US size 8 underwear size in UK sizing?
A women's US size 8 generally converts near UK 12.
What is a women's US size 8 underwear size in EU sizing?
A women's US size 8 generally converts near EU 38.
What does medium underwear convert to?
A general women's medium often corresponds to US 8 to 10, UK 12 to 14, and EU 38 to 40, but brand ranges vary.
Are underwear size conversions exact?
No. Waist ranges, hip grading, rise, coverage, stretch, seams, and compression differ by brand.
Can men's underwear sizes be converted by trouser size?
Trouser waist can provide a starting point, but the actual body waist and product chart are more reliable.