Plus Size Bra Fit and Size Guide
Why the right bra size matters
A bra that fits well supports your bust, sits level, and stays comfortable from morning to night. Many women wear a band that is too loose or cups that are too small without realizing it, because sizes vary by style and change over time.
This guide shows how to measure at home, how to tell if a bra fits, which Ashley Stewart bra styles suit different needs, and how to care for them. Our bras come in bands 38 to 46 with cups D, DD and DDD, plus F, G and H cups in our extended sizes (bands 42 to 46), so you can find support built for fuller busts.
How to measure your bra size
Wear a lightly lined or unlined bra and stand straight. Use a soft tape measure and keep it level all the way around.
- Band: measure snugly around your ribcage, directly under your bust. Round to the nearest even number. That is your band size, for example 40.
- Bust: measure around the fullest part of your bust with the tape loose enough not to press in.
- Cup: subtract your band measurement from your bust measurement. Each inch of difference is one cup size.
| Difference (inches) | 4 | 5 | 6 | 7 | 8 | 9 |
|---|---|---|---|---|---|---|
| Cup | D | DD | DDD | F | G | H |
For example, a 40 inch band and a 46 inch bust is a difference of 6, so you start with a 40DDD. Treat the result as a starting point, then check it against the size chart on the product page, because styles fit a little differently. If a cup feels too small, try the same band in the next cup up. If the band feels too loose, try one band size down and go up a cup to keep the same cup volume.
Prefer a visual walkthrough? Use our bra size calculator and measuring chart, which includes a step-by-step measuring video.
Signs your bra fits, and signs it does not
| Check | A good fit | Time for a different size |
|---|---|---|
| Band | Sits level around your back and feels snug on the loosest hook | Rides up your back or leaves deep marks |
| Cups | Your bust fills the cup with no gaps or spilling | Gaping fabric, or bulges at the top or sides |
| Underwire | Lies flat against your ribcage and sits fully around the breast | Sits on top of breast tissue or digs under the arm |
| Center | The center gore rests flat against your breastbone | The center lifts away from your chest |
| Straps | Stay in place and carry only a small share of the weight | Dig into your shoulders or keep slipping |
A simple test: fasten the bra on the loosest hook, lean forward, and settle your bust into the cups. Then stand up and check the band. If it lifts when you raise your arms, the band is too big.
Choose a bra style
| Style | Best for | What to know |
|---|---|---|
| T-shirt bra | Everyday wear under tees and knits | Lightly lined microfiber underwire cups, smooth under clothes (76% nylon, 24% spandex) |
| Butterfly bra | Maximum support and lift | Patented Ashley Stewart design: underwire cups with foam bump pad, adjustable gel straps and a double-wrap back with 4 hook closures |
| Convertible bra | Racerback, halter and strapless looks | 5 and 6 way styles with convertible straps, silicone stay-in-place lining on some |
| Wireless bra | Comfort days and relaxing | No underwire, soft lace and mesh; front-close posture bra for easy on and off |
| F, G and H cups | Fuller busts needing extra-size cups | Extended size butterfly styles in bands 42 to 46, with F, G and H cups |
Our bras are made from stretchy nylon and spandex blends, so they move with you. Most butterfly styles have a double-wrap back with 4 hook closures for a secure band. If you are between styles, start with a T-shirt or butterfly bra, then try a wireless bra for lounging.
The Ashley Stewart patented Butterfly Bra
Our Butterfly Bra is a patented design, exclusive to Ashley Stewart, and the bra we call our most-loved. The patent covers its double-wrap back: double back wrap panels with four hook-and-eye closures at each strap. They conform to your curves for superior support and help smooth bulges for a polished look under clothes. A golden butterfly charm is the finishing touch.
The double-wrap back also helps with fit. A wider, firmer band keeps the bra level and snug, so the band does the work and your straps carry less of the weight. When a new bra is on the loosest hook, you can move in a hook as the band relaxes with wear.
The Butterfly Bra comes in several styles:
- Full Coverage: lace-trimmed, with lightly lined underwire cups and a foam pad for lift.
- Plunge: a deeper neckline that disappears under low-cut tops.
- Balconette: a low-cut fit with molded underwire cups.
- 6 Way Convertible: wear it six ways, with detachable straps and an extra set of clear straps for strapless looks.
- Wireless: the same patented double-back wrap without underwire, with wide padded gel straps and concealed elastic for natural lift.
Sizes run in bands 38 to 46 with D to DDD cups, and in extended sizes with F, G and H cups. Shop the full Butterfly bra collection or the F, G and H cup bras.
Care and when to replace
Follow the care label on each bra. For most of our bras that means hand wash in cold water, use non-chlorine bleach only when needed, do not wring, line dry, and do not iron. Hand washing and air drying protect the stretch fibers and the underwire.
Rotate between two or three bras so each one rests a day between wears. Plan to replace a bra every 6 to 12 months with regular wear, or sooner if the band stretches out, the underwire pokes through, or the cups lose their shape.
Ready to find your fit? Browse all bras, or start with underwire and wireless styles.
Plus size bra FAQ
How do I measure my bra size at home?
Measure snugly around your ribcage under your bust for the band, then around the fullest part of your bust. The difference in inches gives your cup size.
How should a bra fit?
The band sits level and snug, the cups hold your bust with no gaps or spilling, the underwire lies flat, and the center rests against your breastbone.
How do I know if my band is too big?
If the band rides up your back or lifts when you raise your arms, it is too loose. Try one band size down and go up a cup.
What is sister sizing?
Sister sizes keep the same cup volume with a different band. Going down a band size means going up a cup, for example 40DD to 38DDD.
What bra is best for full support?
A butterfly bra has underwire cups with a foam bump pad, adjustable gel straps and a double-wrap back with 4 hook closures for maximum support.
Which bra is best for everyday wear?
A lightly lined microfiber T-shirt bra is smooth under clothes and comfortable all day.
Are wireless bras supportive?
Yes, many wireless styles offer good support with soft cups and wide wings. A front-close posture bra adds easy wear and back support.
How often should I replace my bra?
Every 6 to 12 months with regular wear, or sooner if the band stretches, the wire pokes through or the cups lose shape.
What is the Ashley Stewart Butterfly Bra?
It is a patented bra design exclusive to Ashley Stewart, known for its double-wrap back with four hook-and-eye closures at each strap, which gives superior support and a smooth look. It comes in full coverage, plunge, balconette, 6 way convertible and wireless styles.
