Use a tape measure in inches around her waist (narrowest point), high hip (just below belly button), and low hip (widest part). Compare to our US chart here:
👉 Size Chart – Inches
Quick tips for fit:
- UnderSwim (OG + G-Fit): Runs snug. If she’s in between, size up to help create a flush seal around the legs.
- Period Swim Bikini Bottoms: Run a little roomy. If in between, size down for best fit under swimwear.
- UnderDance: Designed for a stay-put fit under leotards. True to size > roomy.
- UnderLiner: More flexible fit, good for light flow or just-in-case wear.
- Bumpers Briefs: True to size with soft stretch — designed for everyday comfort.
Need help? Send us her measurements or the flat-lay width of her current undies and we’ll take a look.
Aug 15, 2025
