Are you looking for the perfect swimsuit for your body type? You are not alone. Every year, thousands of women order a swimsuit online, put it on with anticipation… and something feels off. The problem is never your body. It is the gap between standardized sizing and the reality of your shape.
This comprehensive guide finally gives you the clear answers that no one else has provided: how to measure yourself, which cut to choose based on your body type, and why MITCH By AEF customers find their perfect fit on the first try.
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Why is finding the right swimsuit size so complicated?
Standard sizes do not measure your body
The first thing to understand: ready-to-wear sizes do not measure a body; they measure an average. In France, the NF EN 13402 standard proposes a system based on chest, waist, and hip measurements. However, this standard does not capture the thousands of variations in proportions that exist from one woman to another.
The result: two women wearing the same size on the label may have very different chest, waist, and hip measurements. And that is where the unpleasant surprises begin when the package arrives.
Fabric and elastane change everything
Elastane (Lycra®, a registered trademark of Invista) is the fiber that allows a swimsuit to stretch and regain its shape. In swimwear, the percentage of elastane varies between 15% and 30% depending on the cuts and the areas of the body. A fabric with 20% elastane will exert different tension depending on whether it covers a flat area (the back) or a curved one (the chest or hips).
This is why two swimsuits sold in the same size can offer radically different support depending on the body volumes wearing them.
The lining also plays a crucial role. A quality swimsuit features an inner lining whose composition and textile tension differ from the outer fabric. This lining must be flexible enough to avoid uncomfortable compression, but firm enough to provide genuine support. An unlined swimsuit will feel "limp" or lack structure, even if the size matches your measurements perfectly.
Pattern variations constitute the most invisible and decisive variable. An experienced swimsuit pattern maker knows that:
- the angle of hip cutouts radically changes the perception of volume,
- crotch height modifies the visual balance between the pelvis and thighs,
- the position of the straps influences the perception of the shoulders,
- the placement of a princess seam entirely alters the curve of the bust.
At MITCH By AEF, every product page details the fabric composition, type of lining, and cut specifics so you know exactly what you are buying.
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What swimsuit size should you choose? (Size chart in cm)
Why sizes vary so much by brand and country
If you have ever bought a swimsuit online, you have surely noticed that size charts vary considerably from one brand to another. This is no coincidence: there is no universal, binding swimsuit size.
In Europe, the EN 13402 and ISO 8559 standards serve as a base, but every country and brand interprets these recommendations in its own way. A French size 38 does not correspond exactly to an Italian or Spanish size 38.
This is why at MITCH By AEF, we believe that a detailed size chart, with measurements in centimeters, is the only truly reliable information.
Practical tip: Ignore the size label. Measure yourself. Compare your measurements to the chart provided on each MITCH By AEF product page. It is the only method that really works.
How to measure yourself correctly to choose your swimsuit online
There is no mystery: the centimeter measurement method is the only one that truly works, regardless of the site or brand. Here are the 4 essential measurements:
- Bust measurement: measured at the fullest part of the chest, with the tape measure perfectly horizontal across the back. Do not pull tight. Breathe normally.
- Waist measurement: measured at the natural hollow of the waist, usually 2 to 3 cm above the navel. Do not pull your stomach in.
- Hip measurement: measured at the widest part of the pelvis and buttocks. Stand straight with feet together.
- Under-bust measurement (optional but very useful for underwire or integrated cup swimsuits): measured just below the breasts, at the base of the chest.
Important: Take your measurements while in thin underwear or nude, standing, arms at your sides, in front of a mirror. Use a flexible tailor's tape measure, not a rigid one.
On every MITCH By AEF product page, the size chart in cm is available so that you can compare your measurements directly.
Which swimsuit for my body type? The complete guide by silhouette
The morphological classifications used in image consulting and textile pattern making rely on a simple principle: observing the relative proportions between the shoulders, waist, and hips, understanding how volume is distributed, and, in swimwear, choosing cuts that naturally highlight your features.
These classifications are trends and indicative benchmarks, not boxes you absolutely have to fit into.
Swimsuit for X body type (hourglass): flattering cuts
Proportions: Shoulders and hips aligned, well-defined waist. This is the silhouette often associated with the "hourglass."
Swimsuits that suit you best:
- One-piece swimsuits with side cutouts that emphasize the waist
- High-waisted bikinis that highlight curves
- Bikini tops with light underwire for optimal support
Avoid: Straight cuts that hide your defined waist. Bikini tops without any support for a fuller bust.
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Swimsuit for A body type (pear): balancing top and bottom
Proportions: Hips are wider than the shoulders. The lower body is more voluminous.
Swimsuits that suit you best:
- Colorful or patterned tops, or those with details (ruffles, embroidery) to draw the eye upward
- Solid, dark-colored bottoms, in a classic or high-waisted cut
- One-piece swimsuits with a detailed neckline (open back, crisscross, V-neck)
Avoid: Bottoms with loud patterns that accentuate hip volume. Minimalist tops without any detail.
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Swimsuit for V body type (inverted triangle): softening the shoulders
Proportions: Shoulders are wider than the hips. The volume is concentrated in the upper body.
Swimsuits that suit you best:
- Bikinis with thin straps or crisscross straps in the back
- Bottoms with side ruffles or bold prints to rebalance the figure
- One-piece swimsuits with a plunging neckline
Avoid: Tops with voluminous shoulders or very thick straps. Bottoms that are too plain, which create an imbalance.
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Swimsuit for H body type (rectangle): creating curves
Proportions: Shoulders, waist, and hips are relatively aligned. The silhouette is straight and elegant.
Swimsuits that suit you best:
- One-piece swimsuits with waist details (belt, cutout, ruching)
- Bikinis with prints and textures that create movement
- Bandeau or triangle tops to highlight the décolleté
Avoid: Ultra-straight cuts and head-to-toe solid colors, which emphasize verticality.
See swimsuits for H body types →
Swimsuit for O body type (curvy): comfort and support above all
Proportions: Volumes are generously distributed around the bust and stomach.
Swimsuits that suit you best:
- One-piece swimsuits with structuring fabric and a V-neckline that elongates
- Vertical color-blocking to create a lengthening line
- Well-structured tankinis that do not constrain the stomach
- Swim skirts that drape comfortably
Avoid: Horizontal cutouts that cut off the silhouette. Bandeau tops that compress without supporting. Fabrics that are too thin and lack hold.
See swimsuits for O body types →
FAQ: Your questions about swimsuit sizes
Can I wear a one-piece swimsuit if I have a large bust?
Absolutely. A well-designed one-piece swimsuit for a full bust incorporates reinforced lining, wide non-stretch straps, and sometimes light underwire. The support of a good one-piece swimsuit can be superior to that of a classic triangle bikini.
How do I know if a swimsuit runs large or small?
The only reliable method: consult the size chart in centimeters on the product page. The terms "runs large" or "runs small" are subjective. Your measurements in cm never lie. On MITCH By AEF, every product page includes this chart.
Does my swimsuit size match my jeans size?
No. This is one of the most common mistakes. Swimsuits follow their own sizing logic, which is often different from ready-to-wear. Never rely on your jeans size to choose a swimsuit. Take your measurements and consult the conversion chart.
Should I size up to be more comfortable?
Not necessarily. A swimsuit that is slightly too large loses its support and shape, which can be more uncomfortable than a fitted swimsuit. Rely on your exact measurements and the brand's chart.
How do I take care of my swimsuit so it keeps its shape?
Rinse it with cold water immediately after each use, without wringing it out. Wash it by hand with mild soap. Never put it in the washing machine or tumble dryer, as heat destroys the elastane. Let it dry flat, in the shade. A well-maintained swimsuit retains its properties much longer.
Ready to find your ideal swimsuit?
You now know your body type, your measurements, and the cuts that flatter you. All that's left is to choose.
Discover the entire MITCH By AEF women's swimwear collection →