Final Hours! Up to 50% off (SHOP NOW)
  • usa / $usd
  • can / $cad
  • intl / $usd
  • Size Guides
  • BlogOpens in a new window
KT by Knix Logo
  • Sale
  • Up to 50% off Period Undies
  • Up to 25% off Period Kits
  • Up to 30% off Period Swim
  • Up to 30% off Period Active
  • $25 Leakproof Shortie
  • Shop All
  • Last Call
  • Gift Card
  • Accessories
  • We Wrote A Book!
  • Size Guides
  • BlogOpens in a new window
    • usa / $usd
    • can / $cad
    • intl / $usd
  • Give Feedback
Looking for adult sizes? Shop Opens in a new window
you've got this in the bag
Your Cart
your cart is empty.
But You're full of potential
  • Sale
  • Period Undies
  • Period Swim
  • Period Active
  • Period Kits
  • Sleep
  • Best Sellers
  • Leakproof Shortie
  • Gift Card

Keep in touch

Stay in touch to get exclusive offers and be the first to know about the latest product releases. Unsubscribe anytime.

Thanks! You’re on the list!
Terms & Privacy

By submitting your email, you agree to our terms & conditions

  • Sale
  • Up to 50% off Period Undies
  • Up to 25% off Period Kits
  • Up to 30% off Period Swim
  • Up to 30% off Period Active
  • $25 Leakproof Shortie
  • Shop All
  • Last Call
  • Gift Card
  • Accessories
  • We Wrote A Book!

  • Contact Us
  • Returns & Exchanges
  • Shipping
  • Sizing Help
  • 16% Off Student Discount Opens in a new window

  • About Us
  • How We're Giving Back
  • BlogOpens in a new window
  • Reviews
  • Visit Us IRL

Give Us A Follow

  • Opens in a new window
  • Opens in a new window
  • Opens in a new window
  • Opens in a new window
  • Opens in a new window
Refer a friend to give $15 & get $15 off!
| Opens in a new window
  • ©2025 Knix All Rights Reserved
    • |
  • Terms & Conditions
    • |
  • Accessibility
    • |
  • Privacy Policy
    • |
  • California Privacy Rights
    • |
  • Privacy Choices
Teen Underwear Size Chart
KT Period Underwear is designed for smaller and growing bodies to fit teens and tweens

For adult sizes and styles, check out Knix Opens in a new window.
KT Size Hips Kids Pant Size Adult Pant Size
XXS 25” - 27” 7 ---
XS 28” - 30” 8 - 10 ---
S 31” - 34” 12 - 14 00 - 2
M 35” - 38” 16 - 20 4 - 8
L 39” - 42” --- 10 - 14
XL 43” - 46” --- 16 - 18
XXL 47” - 50” --- 20 - 22
Find the Perfect Fit

1. Hips

Stand with your feet together and measure around the widest part of your hips and bottom. Keep the measuring tape parallel to the floor.

Still Not Sure What Size To Get?

Book a Virtual Fitting with a team member and get 1:1 help over video chat.
Teen Swimwear Size Chart
KT swimsuits are designed for smaller and growing bodies to fit teens and tweens

For adult sizes and styles, check out Knix Opens in a new window.
KT Size Band Hips Kids Pant Size Adult Pant Size
XXS 23 3/4" - 25 1/4" 25” - 27” 7 ---
XS 25 1/4" - 26 3/4" 28” - 30” 8 - 10 ---
S 26 3/4" - 28 1/4" 31" - 34" 12 - 14 00 - 2
M 28 1/4" - 29 3/4" 35” - 38" 16 - 20 4 - 8
L 29 3/4" - 31 1/2" 39” - 42” --- 10 - 14
XL 31 1/2" - 33 1/2" 43” - 46” --- 16 - 18
XXL 33 1/2" - 35 1/2" 47” - 50” --- 20 - 22
Find the Perfect Fit

1. Band

First, measure around the torso right below the breast

2. Hips

Stand with your feet together and measure around the widest part of your hips and bottom. Keep the measuring tape parallel to the floor.

Still Not Sure What Size To Get?

Book a Virtual Fitting with a team member and get 1:1 help over video chat.
Teen Activewear Size Chart
KT activewear is designed for smaller and growing bodies to fit teens and tweens

For adult sizes and styles, check out Knix Opens in a new window.
KT Size Hips Kids Pant Size Adult Pant Size
XXS 25” - 27” 7 ---
XS 28” - 30” 8 - 10 ---
S 31” - 34” 12 - 14 00 - 2
M 35” - 38” 16 - 20 4 - 8
L 39” - 42” --- 10 - 14
XL 43” - 46” --- 16 - 18
XXL 47” - 50” --- 20 - 22
Find the Perfect Fit

1. Hips

Stand with your feet together and measure around the widest part of your hips and bottom. Keep the measuring tape parallel to the floor.

Still Not Sure What Size To Get?

Book a Virtual Fitting with a team member and get 1:1 help over video chat.
Teen Leotard Size Chart
KT leotards are designed for smaller and growing bodies to fit teens and tweens

For adult sizes and styles, check out KnixOpens in a new window.
KT Size Band Hips
XS 28" 25” - 27”
S 30" 28” - 30”
M 32" 31” - 35”
L 34" 36” - 40”
XL 36" 41” - 44”
XXL 38" 45” - 48”
Find the Perfect Fit

1. Band

First, measure around the torso right below the breast

2. Hips

KT Leotards are designed to sit on the hips, so measure around the widest part of the hips and refer to the chart above to find the best fit.

Still Not Sure What Size To Get?

Book a Virtual Fitting with a team member and get 1:1 help over video chat.
Teen Sweatshirt Size Chart
Size Bust Hips
XS 27” 25" - 27"
S 30” 28" - 30"
M 34" 31" - 35"
L 37” 36" - 40"
XL 40” 41" - 44"
XXL 40” 45" - 48"

Still Not Sure What Size To Get?

Book a Virtual Fitting with a team member and get 1:1 help over video chat.
Freestyle Leakproof Tights Size Chart
Size Hips Height Weight
XS/S 25" - 30" 4'2" - 5'1" 65 - 100 lbs
M/L 31" - 40" 4'9" - 5'6" 105 - 130 lbs
XL/XXL 41" - 48" 4'11" - 5'6" 135 - 170 lbs

Still Not Sure What Size To Get?

Book a Virtual Fitting with a team member and get 1:1 help over video chat.
Thigh Savers Size Chart
KT Products are designed for smaller and growing bodies to fit teens and tweens

For adult sizes and styles, check out Knix Opens in a new window.
KT Size Hips Kids Pant Size Adult Pant Size
XXS 25” - 27” 7 ---
XS 28” - 30” 8 - 10 ---
S 31” - 34” 12 - 14 00 - 2
M 35” - 38” 16 - 20 4 - 8
L 39” - 42” --- 10 - 14
XL 43” - 46” --- 16 - 18
XXL 47” - 50” --- 20 - 22
Find the Perfect Fit

1. Hips

Stand with your feet together and measure around the widest part of your hips and bottom. Keep the measuring tape parallel to the floor.

Still Not Sure What Size To Get?

Book a Virtual Fitting with a team member and get 1:1 help over video chat.