How to know if a swimsuit will fit before you buy online

Updated: 05.11.2026

In short: Measure your bust, underbust, waist and hips, then match them to the brand's own size chart. Read reviews for words like "runs small" or "long torso". Many stores won't take swimwear back, so check fit before you order. Last step: try the swimsuit on your own photo with AnyTry to see the cut, color and coverage on your body.

🔗 amazon.com/dp/…✓ Ready in 30 sec

Want to skip the guessing? Try a swimsuit on your photo.

Step 1: Take 4 measurements (2 minutes)

Use a soft tape. Wear a thin bra or nothing on top. Keep the tape level and snug, not tight.

For one-pieces, also measure your torso loop: from the top of one shoulder, down between your legs, and back up to the same shoulder. It tells you if a one-piece will be long enough.

Need help? See the swimsuit size chart guide.

Step 2: Use the brand's chart, not "your usual size"

Every brand sizes differently. A medium at SHEIN, a medium from an Amazon brand and a medium at Zara can fit very differently.

• Open the size chart on the product page itself.
• Match your biggest measurement for that piece.
• Between sizes? Go up for one-pieces. For bikini bottoms with side ties, the smaller size often works.
• Check if sizes are in cm or inches. This mix-up is common.

Step 3: Read reviews for fit words

Reviews tell you what the chart can't. Search the reviews page for:

• "runs small" or "runs large"
• "long torso" or "short torso"
• "no support" or "great support"
• "see-through" or "thin fabric"
• "cheeky" (less coverage in back)

If three or more people say the same thing, believe it. Reviews with photos from buyers with a similar shape to yours are the most useful.

Step 4: Check the fabric and build

Fabric decides how a swimsuit sits on you after a few swims.

• Nylon/spandex blend (15–25% spandex): stretchy, holds shape.
• Polyester blend: lasts longer in chlorine, a bit less stretch.
• Lined front and crotch: less see-through when wet.
• Removable cups or underwire: more support for a fuller bust.
• Adjustable straps: help if you have a long or short torso.

Step 5: See it on your body, not the model's

Model photos show one body type, posed and edited. That is not how it will look on you.

With AnyTry, you upload one full-length photo of yourself and a photo, screenshot or link of the swimsuit. It works with Amazon, SHEIN, ASOS, Zara or any store. In about 30 seconds you see that exact swimsuit on you, with your own shape, skin tone and pose.

Not sure? See it on you: Try a swimsuit on your photo.

Try 5 styles in a few minutes and keep only the ones that look right. Remember: try-on shows cut, color, print and coverage. Your size still comes from your measurements.

Quick checklist before you click "buy"

• Measurements taken and matched to this brand's chart
• Reviews checked for fit words
• Fabric and lining look solid
• Return rules read on the store's return page
• Swimsuit tried on your own photo

See it on you before you buy

You've done the measuring. Now check the look. Upload your photo and the swimsuit link, and see the cut and color on your real body in about 30 seconds.

Try a swimsuit on your photo

FAQ

Can I return a swimsuit bought online?

Often it's hard. Many stores treat swimwear and lingerie as final sale or only accept returns with the hygiene liner and tags, so check the store's return page.

Does a virtual try-on show the exact size?

No. It shows cut, color, print and coverage on your body. Size comes from your measurements and the brand's chart.

What photo works best for try-on?

A full-length photo in fitted clothes, good light, facing the camera. Only use your own photo; you must be 18+.

Should I size up or down in swimwear?

Between sizes, size up for one-pieces and tops with a band. Tie-side bottoms are easier to adjust, so the smaller size often works.