Finding Your Size

WunderUndies are true to size.

The briefs typically land just below the navel so that is where you should measure for your best fit.

The boxers typically land just above the navel at the natural waist so that is where you should measure for the best fitting boxers.

If you are between sizes, we recommend sizing up.

Check out the images below from fans of WunderUndies showing how different sizes fit differently shaped bodies. Unfortunately we don't have a photo for every size but it gives you a good idea.

Kids Sizes vs Adult Sizes

The width for our XS briefs and S boxers are very close to our size 12 flat seam kid sizes. For the briefs, the biggest differences is that the kids have more full bum coverage. The boxers, on the other hand, are designed for much taller people than the kid sizes. If you are a person who is considering our smallest sizes, you may fit into a size 12 kid size depending on your height and fit preferences.

Adult Size Chart


 Size Hips Waist (boxers) Low Waist (briefs)
XS 33" - 35"
29" - 31"
S 35" - 38" 30" - 33" 32" - 34"
M 38" - 41" 33" - 35" 35" - 37"
L 41" - 44" 35" - 38" 38" - 40"
XL 44" - 47" 38" - 42" 41" - 43"
2X 47" - 51" 42" - 45" 44" - 47"
3X 51" - 55" 45" - 48" 48" - 51"
4X 55" - 58" 48" - 51" 52" - 55"