Do not automatically carry an S, M or number from one brand to the other. Make separate decisions for the top, bottoms and one-piece; measure the least adjustable area and always check the current chart for that design.
| Garment | Oysho | Calzedonia | SIZES tip |
|---|---|---|---|
| Bikini tops | The range includes triangle, bandeau, halter, underwired, wireless and removable padding designs | The official guide uses bra-style numbers and combines bust with underbust | Measure both circumferences and check the top structure |
| Bikini bottoms | Classic, high-rise, Brazilian and adjustable cuts offer different coverage | The official guide relates size to waist and hips | Prioritise hips, coverage and stability as you move |
| One-piece | Fit changes between soft, bandeau, halter and compressive designs | The one-piece chart combines bust, underbust, waist and hips | Add a torso-length check |
| Adjustable styles | Straps, ties and removable pads let you refine the fit | Many tops and bottoms are sold separately with different structures | Do not use adjustment to compensate for the wrong band or cup |
| Shaping or compressive | Check the compression level stated for the design | Check whether the suit is described as shaping, control or a specific fit | It should support without restricting breath or movement |
Two systems that do not translate through one equivalence
The official Oysho guide separates categories such as bikinis and swimsuits, while the current collection includes tops and bottoms with very different structures. The official Calzedonia guide separates tops, bottoms and one-pieces: tops use bust and underbust, while bottoms and swimsuits add waist and hips.
That is why “an M in one brand equals an M in the other” is not enough. Even within one brand, a tie triangle, an underwired balconette and a bandeau work differently. Read the size together with the pattern and product description.
How to compare bikini tops
Calzedonia's current top chart uses bra-style numbers and bust and underbust ranges. At Oysho, open the guide or product page and use the reference supplied for that top. In both brands, the useful measurement starts around the fullest part of the bust and continues directly underneath.
Then look at construction. An underwired top needs the cup to surround the bust and the band to stay horizontal. An adjustable triangle gives more freedom but should not shift. A bandeau relies especially on a stable band. If you have to tighten the straps fully to stop the top dropping, check the underband.
SIZES tip: if the band works but the cup does not, look for another cup size or shape before changing the whole circumference.
How to compare bikini bottoms
Calzedonia's official guide relates bottoms to waist and hips and shows combined labels such as 1/XS, 2/S and 3/M. Oysho offers different rises and coverage depending on design. Instead of translating the letter alone, compare centimetres and decide how much coverage you want.
Tie-side bottoms can adapt at the waist, but the centre still needs to cover as intended. A high waist should settle without rolling. A Brazilian cut gives less coverage even when the size is right. When in doubt, choose by the least adjustable area and check the fit while sitting and walking.
A one-piece needs one extra check
Calzedonia publishes bust, underbust, waist and hip references for one-pieces. Oysho offers suits with different necklines, straps, coverage and compression levels. Those horizontal measurements are the start, but the garment also has to travel along your torso.
If the shoulders or crotch pull, the neckline shifts or the suit rides up, you may need more length even when bust and hips fit. If the waist is loose but torso length is right, try another pattern before sizing down and creating tension elsewhere.
What to do between two sizes
For fixed-band tops, prioritise underbust: it should support without restricting. For adjustable bottoms, use coverage and hip measurement. For one-pieces, identify the dimension that most limits the pattern. Sizing up may give length and hip room but open the neckline; sizing down may feel firmer but shorten the torso.
Do not look for an automatic rule. State the specific risk and choose the design that solves it. If your body needs different sizes on top and bottom, use separates. If a one-piece makes you choose between bust and hips, a different pattern is usually better than forcing the size.
Movement test before deciding
With liners and tags intact, lift your arms, sit, bend and mimic a swimming stroke. The band should not ride up, the bust should remain contained, the waist should not roll and the suit should not pull from the shoulder. You should also breathe normally.
Read return conditions before trying swimwear bought online. Hygiene liners matter. A careful fitting lets you assess the garment without affecting a possible return.
How to use SIZES
Save bust, underbust, waist and hips in your profile. When a design works, add brand, size, top or bottom type, coverage and a short note: “firm band”, “roomy cup”, “short torso” or “adjustable bottoms”. This keeps one purchase from becoming a universal rule.
For more context, read how to choose a bikini or swimsuit size online, what to do between two sizes and why your size changes between brands.
Final recommendation
Oysho and Calzedonia do not need one universal winner. In both brands, the result depends on the design. Use the current official chart, measure the least adjustable area and test movement. If you buy a top and bottoms separately, decide each piece from its own measurements.
Frequently asked questions
Do Oysho and Calzedonia bikinis fit the same?
Do not assume so. The systems and fit change between tops, bottoms, one-pieces and individual designs. Check the current product chart.
Which measurement matters most for a bikini top?
Compare bust and underbust. The band should support and the cup should contain without cutting in or leaving large gaps.
Can I buy the top and bottoms in different sizes?
Yes, when pieces are sold separately. It is useful when your bust and hips do not sit in the same size.