How to measure yourself for swimwear that actually fits

Standard swimwear sizing uses bust, waist, and hip measurements and assumes a set of proportions between them. Most bodies do not match those proportions exactly, which is why off-the-rack swimwear fits some people well and others not at all. Understanding which measurements matter and how they relate to the pattern helps you choose the right size and identify when made-to-measure is worth considering.

The measurements that matter most ¶

Bust and underbust measurements together determine the cup volume of a bikini top or one-piece. The bust measurement alone does not tell you how much volume the cup needs to contain. Two people with the same bust measurement can have very different underbust measurements, which means they need different cup depths.

Hip measurement for swimwear is taken at the fullest point of the hip, not at the waist. For high-waist briefs, the waist measurement is also relevant. For Brazilian-cut briefs, the hip measurement is the primary determinant of fit.

• Bust: measured at the fullest point, tape parallel to the floor
• Underbust: measured directly under the bust, tape snug but not tight
• Waist: measured at the narrowest point
• Hip: measured at the fullest point, usually 20 to 23cm below the waist
• Torso front: from the shoulder at the base of the neck to the crotch
• Torso back: from the centre back neck to the crotch

When to consider made-to-measure ¶

Made-to-measure is worth considering when your measurements fall between standard sizes in more than one dimension, or when the proportions between your measurements differ significantly from the standard. A common example is a large difference between bust and underbust measurements, which means standard cup sizing will not fit correctly regardless of which size you order.

It is also worth considering if you have a longer or shorter torso than average. One-pieces are particularly sensitive to torso length. A piece that is too short pulls down at the straps and gaps at the leg openings. A piece that is too long bunches at the crotch.

Measuring takes ten minutes and removes most of the uncertainty from buying swimwear online. The size guide on each Ox Tool product page includes the full measurement ranges for every size.