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How to Find Your THINX Size

Shopping for undies online can be hard, especially if you are trying an entirely new brand! I really want everyone to be able to experience the awesome benefits of period underwear though, so I've put together this guide to finding your perfect fit in THINX period undies.

THINX sizing Nourished Life Australia Buy now

I know it can be really hard to find the right size when shopping online, especially when shopping for underwear, and even more so when you're trying a new brand. Here at Nourished Life, we stock a range of period underwear, including awesome brand THINX! Period undies are amazing for replacing pads, tampons or menstrual cups, or even just for added protection and peace of mind during your period. They come in a range of sizes and styles though, so it's important to make sure you're ordering your perfect pair.

High waist period underwear

How to find your perfect THINX fit

THINX period undies are true to size, so it's best to go for your usual size. It's also really important to note though that the special technology which keeps us leak-free makes their sizes more of a snug fit than average undies... this means that they will feel a bit different to your regular pairs, maybe a bit tighter, but rest assured they are meant to fit that way!

To find your perfect size, it's recommended to use a measuring tape and check your measurements against THINX sizing for the most accurate fit.

Simply measure your waist just beneath your belly button, and your hips around the largest part of your buttocks.

Thinx underwear how to choose

Size Extra Small (XS)
• Waist 61-64cm
• Hip 89-91cm

Size Small (S)
• Waist 66-69cm
• Hip 94-97cm

Size Medium (M)
• Waist 71-74cm
• Hip 99-102cm

Size Large (L)
• Waist 76-79cm
• Hip 104-107cm

Size Extra Large (XL)
• Waist 81-85cm
• Hip 109-113cm

Thinx cotton period underwear bikini


To find the perfect fit in the THINX range for teenagers, you should also measure the waist and hips before purchasing. Just like the main range, THINX BTWN styles are true to classic sizing for girls' underwear and clothing, but may feel a tad snug. Since they are specially designed for tween and teen body shapes, THINX BTWN may not be suitable for adult shapes as they feature snugger leg holes, a narrower gusset, and straighter hips.

THINX teen period undies

Size 9-10
• Natural Waist 60-62cm
• Lower Waist 68.5-71cm
• Hip 73.5-77cm

Size 11-12
• Natural Waist 63-64cm
• Lower Waist 74-77cm
• Hip 80-84cm

Size 13-14
• Natural Waist 65.5-67cm
• Lower Waist 80-83cm
• Hip 88-92

Size 15-16
• Natural Waist 71-74
• Lower Waist 87-91
• Hip 96-100

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