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Bra Fitting Guide

38GG Bra Size Guide

38GG bra size explained: measurements, sister sizes, international equivalents, and fit tips.

By Claire Bennett
2 min read • Updated Nov 2026
Direct Fit Answer

A 38GG bra means a 38-inch band with a GG cup, or roughly a 8-inch difference between underbust and bust measurement.

This is a real, ordinary size. The challenge here is retail availability, not anything unusual about the size itself.

38GG bra size chart showing 37" to 38" underbust, 48" bust, 2340 cc cup volume, and sister sizes
Size 38GG Chart
US 38GG fits a 37" to 38" snug ribcage and 48" full bust (~2340 cc per cup), matching UK 38GG and EU 85J.Bra-SizeCalculator.com Guide
Size 38GG Quick Reference

38GG Measurements, Cup Volume & Global Sizes

Verify My Size
Snug Underbust Ribcage37" – 38"94–97 cm ribcage
Fullest Bust Perimeter~48"+10" over band (122 cm)
Single-Cup Volume~2340 ccPair tissue ~9.8 lbs (4446 g)
Bralette & Lounge ScaleXL-Busty / 1X-CurvyAlpha wireless equivalent
Snugger Band Sister36K
View 36K →
Target Size38GG (~2340 cc)
Baseline
Roomier Band Sister40I
View 40I →
38GG Across 7 Global Lingerie Tag Standards
US38J
UK38GG
EU85J
AU16GG
FR100J
IT5J
JPJ85
Size 38GG Picks

Bras That Fit Well in Size 38GG on Amazon

Picked for steady 38-band support and true GG-cup depth, with no paid brand placements.

Search All 38GG on Amazon
Rosewood two-part seamed floral lace full-figure underwire bra with tall center gore and wide strapsTop Pick for Large Bust$44 – $68
Wacoal4.6

Wacoal Women's Retro Chic Full-Figure Underwire Bra

Full Bust Lift & Forward Projection (C–H)

Structured berry high-impact camisole sports bra diagram showing upper mesh bounce panel and wide strapsEditor's Choice$36 – $56
Glamorise4.5

Glamorise Women's No-Bounce Camisole High-Impact Sports Bra

Running, HIIT & High-Impact Bounce Control

Rosewood three-part seamed full-bust plunge underwire bra diagram showing low center gore and side slingTop Pick for Large Bust$52 – $74
Elomi4.7

Elomi Women's Matilda 3-Part Full-Bust Underwire Plunge Bra

Plus-Size & Deep Cup Engineering (DD–K UK)

What a 38GG Actually Looks Like

A 38-inch band sits snugly around your ribcage just under your bust. Paired with a GG cup, that means roughly a 8-inch gap between your underbust and fullest-bust measurement. Raise both arms overhead; if the band rides up more than an inch, it’s too loose regardless of how it felt standing still.

Sister Sizes for 38GG

If 38GG isn’t quite right, the two closest sister sizes are 40G (looser band, bigger cup, same volume) and 36I (snugger band, smaller cup, same volume). Every 2-inch band change pairs with exactly one cup-letter change in the opposite direction, because both numbers describe the same underlying volume.

38GG in Other Sizing Systems

SystemBandCup
United States38″GG
United Kingdom38″FF
Europe (FR/ES/BE)115cmH
Italy115cmI
Japan/Korea95cmH

Fit Tips at This Size

The band should feel snug on the loosest hook when new, since it will stretch slightly with wash and wear. If a specific brand consistently runs small or large for you, the Brand Size Decoder applies that adjustment automatically instead of making you guess.

Want your exact size instead of an estimate? Use the Main Bra Calculator- free, private, takes under a minute.

Common Mistakes at 38GG

Judging fit standing still: many fit problems (band riding up, straps slipping) only show up once you move, reach overhead, or sit down.

Where to Actually Find This Size

Specialty lingerie retailers and brands that specifically design for a wider size range are usually a better first stop than general department stores for this combination.

A Common Myth Worth Clearing Up

A common myth is that larger cup letters always mean an objectively “bigger” body overall. Cup size is about local volume relative to band size, not a measure of overall body size.

Style Recommendations for 38GG

Wireless options can work fine here as long as the band itself has real structure. Wireless doesn’t have to mean unsupportive.

Why This Number Isn’t Permanent

Body measurements can shift slightly with the seasons for some people. A bra that fit perfectly in summer can feel different after a few months, which is normal and worth a quick re-check rather than assuming something’s wrong.

Shopping Online at This Size

Reading recent reviews that mention true-to-size feedback for the exact style (rather than the brand generally) is one of the more reliable ways to predict fit before buying online.

Frequently Asked Questions

Watch for cup gaping or spillage (too small now) versus a band that barely needs tightening on the first hook (too big now). Both are signs to re-measure.
About the FitterChecked Across 7 Sizing Systems
Updated: November 2026
Written & Reviewed ByClaire Bennett• Bra Fit Educator & Founder

Claire Bennett spent over 10 years fitting women in specialty lingerie shops before starting Bra-SizeCalculator.com. She isn't a doctor, and she doesn't make up fake credentials. She shows the exact tape math behind every result so you can shop without guesswork.

10+ Years In-Store Boutique Fitting7 Global Sizing Systems CheckedUnsponsored Fit GuidesHow Our Sizing Works