How-To Guides
Everything you need to start wearing well and make smart garment decisions — written for real beginners and improving wearers.
Bra Size Chart: Band and Cup Conversions Across US, UK, EU and AU Size Runs
Band comes from the snug underbust measurement rounded to the nearest even inch — 81 cm is a 34, and the same rib cage is a 75 in Germany, a 90 in France and a 14 in Australia. Cup comes from the difference between the bust measurement and that band, at roughly 2.5 cm per letter. The four systems agree perfectly up to D and then split, which is why one body is legitimately a 34DD, a 34E and a 75F at the same time.
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How to Measure Your Bra Size — and Why the +4 Rule Still Gets It Wrong
Take three measurements: a snug underbust, a relaxed underbust and a bust measurement taken leaning forward at the hips. Round the snug underbust to the nearest even inch for the band, then subtract that band from the bust figure and count one cup letter per inch. The legacy rule that adds four or five inches to the underbust lands roughly two band sizes too loose and four cup letters too shallow, which is how a 32E ends up labelled 36B.
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Sister Sizes: Which Bra Sizes Hold the Same Cup Volume
Drop the band by one size and go up one cup letter, or raise the band by one and drop one letter, and the cup holds the same volume. A 34D, a 32DD and a 36C are the same volume on three different rib cages. That relationship fixes a band problem without giving up a cup that already worked — and it does nothing at all for a cup that gapes or spills.
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Why a 34DD Isn't a 34DD: Bra Sizes by Brand Across 30 Size Runs
Brands do not share a size run. Each grades outward from its own base block, applies its own band rule, chooses its own cup step and uses one of four incompatible cup alphabets, so the same body is correctly a 34DD in one range, a 32F in another and a 70G in a third. The registry below gives the lettering system, band rule and core range for thirty brands, plus the correction to apply when converting into a body-first standard.
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Eleven Bra Fit Faults and the Measurement That Fixes Each One
Nearly every fault in a bra traces back to the band, and the band is almost always too loose rather than too tight. Diagnose from what the garment does — rides up, gapes, spills, digs, floats — and each symptom maps to one mechanical cause and one specific correction. Some faults are not size problems at all: a stretched band, a migrated wire or a bagged cup is out of conformance, and no size change recovers it.
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What "High Impact" Has to Mean in Centimetres: Sports Bra Support by Cup Size
Low, medium and high impact are marketing categories with no defined threshold behind them. Published breast-biomechanics work puts unrestrained vertical displacement at roughly 2 to 4 cm walking and 8 to 12 cm running, rising with cup size, and a construction has to cut that by 55 to 75 percent to be worth the label. Compression alone stops working around a UK D; above a UK G only wired encapsulation reaches the target.
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Types of Bras: 18 Styles Rated by Cup-Size Ceiling, Coverage and Hold
Eighteen constructions cover the whole category, and each one has a cup letter above which it structurally stops working. That ceiling is a property of the build — gore height, seam count, band width, where the load goes — not of the brand on the label. The matrix below gives the ceiling twice: once for mainstream ranges and once for specialist ranges, because the same nominal style is graded two to four letters further in a specialist run.
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Nine Breast Shapes: How to Identify Yours and the Cup Construction It Needs
A size is a volume. Shape is where that volume sits inside the cup, and no size run carries the information at all — two people measuring an identical 32F can need cups with different depth, different seam placement and a gore 4 cm apart in height. Two measurements sort most of it: root width and projection. The matrix below gives the confirming test, the fault each shape produces, the construction that corrects it and the styles that will never work.
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Underwire vs Wireless: The Cup Size Where Wire-Free Stops Holding
Mainstream wire-free genuinely competes up to about a UK D. A specialist wire-free build — three-part seamed cup, side sling, 5 cm-plus band, four hook rows — competes to about a G. Above that, wire wins on every measure that can be put a number to, and the gap is not close. The head-to-head and the A-to-K Hold Index plot below show exactly where the lines cross.
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What a D+ Bra Must Be Built From: Construction Specs by Cup Size
Bras are graded mathematically outward from a single 34B fit block, so the letters scale while the hardware doesn't. Band width, hook rows, strap width, wire gauge, sling and seam count all have to increase with cup volume and in most ranges they simply don't. The three tables below give the minimum specification at each letter from D to K, in centimetres you can check with a tape.
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Nursing Bra Sizing Through Pregnancy, Milk-In and Weaning
Band and cup move on different clocks. Band moves first and it moves because the ribcage expands, typically one to two sizes by the third trimester; cup moves hardest in the seventy-two hours after milk comes in, when one to three cup letters can appear and then partly recede. Buy nursing bras at around 36 weeks, one band down from where you are then, worn on the loosest hook. The stage table below gives the expected movement and the headroom to allow at each point.
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First Bra Sizing by Measurement, Not by Age
Two measurements and one subtraction give the answer: underbust snug, overbust relaxed, and the difference between them decides both the garment type and the size. Age charts circulating online almost never state a sample and the age ranges they use overlap so heavily that they carry close to no information. The stage table below is indexed to centimetres, with age shown only so you can see how wide the overlap actually is.
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