By Bra Fit Educator Claire Bennett
BraSizeCalculatorHonest Bra Fit Guides
Bra Fitting Guide

38G Bra Size Guide

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

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

A 38G bra means a 38-inch band with a G cup, or roughly a 7-inch difference between underbust and bust measurement. Specialty and extended-size retailers stock this combination more reliably than mall chains, which is normal at this end of the size range.

38G bra size chart showing 37" to 38" underbust, 45" bust, 1580 cc cup volume, and sister sizes
Size 38G Chart
US 38G fits a 37" to 38" snug ribcage and 45" full bust (~1580 cc per cup), matching UK 38F and EU 85G.Bra-SizeCalculator.com Guide
Size 38G Quick Reference

38G Measurements, Cup Volume & Global Sizes

Verify My Size
Snug Underbust Ribcage37" – 38"94–97 cm ribcage
Fullest Bust Perimeter~45"+7" over band (114 cm)
Single-Cup Volume~1580 ccPair tissue ~6.6 lbs (3002 g)
Bralette & Lounge ScaleXL-Busty / 1X-CurvyAlpha wireless equivalent
Snugger Band Sister36H
View 36H →
Target Size38G (~1580 cc)
Baseline
Roomier Band Sister40DDD
View 40DDD →
38G Across 7 Global Lingerie Tag Standards
US38G
UK38F
EU85G
AU16F
FR100G
IT5G
JPG85
Size 38G Picks

Bras That Fit Well in Size 38G on Amazon

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

Search All 38G on Amazon
Champagne blush deep-plunge contour underwire bra with flat scalloped floral mesh-lace trim on linenEditor's Choice$48 – $72
Natori4.6

Natori Women's Feathers Contour Plunge Bra

Shallow, Petite & Close-to-Wide Set

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

What a 38G Actually Looks Like

A 38-inch band sits snugly around your ribcage just under your bust. Paired with a G cup, that means roughly a 7-inch gap between your underbust and fullest-bust measurement.

Check the center gore first. If it doesn’t sit flat against your sternum, the cup is too small even if the band feels right.

Sister Sizes for 38G

If 38G isn’t quite right, the two closest sister sizes are 40DDD (looser band, bigger cup, same volume) and 36H (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.

38G in Other Sizing Systems

SystemBandCup
United States38″G
United Kingdom38″F
Europe (FR/ES/BE)115cmG
Italy115cmH
Japan/Korea95cmG

Fit Tips at This Size

The straps should need almost no tension to stay up. If you’re constantly retightening them, the band underneath isn’t doing its job.

Sold out at your usual store? Check the sister size first. It’s built to hold the same volume from a different band width, and it’s worth trying before assuming the size doesn’t exist in that style.

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

Common Mistakes at 38G

Sticking with a size out of habit for years without re-measuring. Weight changes, hormonal shifts, and even different laundry routines can shift fit gradually enough that you don’t notice until it’s genuinely wrong.

Where to Actually Find This Size

If a specific style is sold out in this exact size, checking the sister size first is often faster than waiting for a restock.

A Common Myth Worth Clearing Up

People sometimes assume a bigger cup letter automatically means less comfort or more visible bulk under clothing. Construction and band fit affect both far more than the letter itself.

Why the Same Size Fits Differently Across Brands

Two brands can list the exact same band and cup number and still fit differently by half a size, purely because of how each cuts its patterns. A wider-set underwire, a shallower cup mold, a stretchier band fabric all change the real-world fit without changing the label.

Making a 38G Last

Rotating between two or three bras rather than wearing the same one daily gives elastic time to recover its shape between wears, which is a simple habit that noticeably extends how long a given size stays accurate.

Style Recommendations for 38G

T-shirt style molded cups give the smoothest look under fitted clothing if that’s a priority alongside fit.

Why This Number Isn’t Permanent

If you’ve changed your exercise routine significantly, muscle and tissue distribution can shift enough to affect band fit specifically, even without a change in overall weight.

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

It depends on the retailer. Mainstream chains often carry a narrower range, while specialty and extended-size retailers stock this range more consistently.
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