If you are a 40 band size then this blogpost will advise you on sister bra sizes for 40 bra band size. Sometimes your usual bra size doesn't fit when you try a different bra brand, range or style. So we have put together a size chart to help you find similar bra sizes for you to try.
What Are Sister Bra Sizes?
If you are finding that your usual bra size isn't fitting then this may be down to a different manufacturer, different brand, or even different style of bra which may mean you have to look for a different size for this bra. Sister bra sizes are the sizes that surround your bra size. With the size of bras sometimes differing because of the manufacturer, brand, style and even country, it is good to know about sister bra sizes so you can try other bra sizes if the one you have doesn't match your usual size.
Size Chart For Sister Bra Sizes For 40 Bra Band Size Based On UK Sizing
If you have a 40 Bra Band Size then take a look at the chart below to help with sister bra sizes. Locate your current bra size and then see what your sister bra size is down or up to see if either of these sizes are a better fit in the current bra that you are finding doesn't fit correctly. Now click your size in the chart below to view the full range of bras in this bra size.
| Sister Size Down | Current Bra Size | Sister Size Up |
| 38A | 40AA | |
| 38B | 40A | 42AA |
| 38C | 40B | 42A |
| 38D | 40C | 42B |
| 38DD | 40D | 42C |
| 38E | 40DD | 42D |
| 38F | 40E | 42DD |
| 38FF | 40F | 42E |
| 38G | 40FF | 42F |
| 38GG | 40G | 42FF |
| 38H | 40GG | 42G |
| 38HH | 40H | 42GG |
| 38J | 40HH | 42H |
| 38JJ | 40J | 42HH |
| 38K | 40JJ | 42J |
| 38KK | 40K | 42JJ |
| 38L | 40KK | 42K |
| 40L | 42KK |
How to Find Your Sister Bra Size
On the size chart, you’ll be able to find your usual size, then discover which sister sizes we would recommend, depending on whether you want to size up or size down.
If you go up in band size, you may need to go down in cup size. If you choose a smaller band size, you may need to choose a larger cup size. Please note that these are just guidelines. Sister sizing can be quite complicated and you may need to choose a different cup size and band size to get the most comfortable fit.
Sister sizes can be other sizes around the initial size. Take a look at our example chart based on UK sizing.
Related Searches: 40E Bra Sizes | 40G Bra Sizes | 40H Bra Sizes | 40I Bra Sizes | 40J Bra Sizes | Underwired Bras | Non Wired Bras
BRAS
Visit our bra page to view our comprehensive bra collection and you can filter by size to see the bras we have in your size and your sister sizes.
With over 200 bras in our collection we have an extensive choice of bras for you to choose from. They come in a range of sizes from 28 to 58 back sizes and AA to N cup sizes. There are many different styles and features to suit your body shape and lifestyle. With so many to choose from it can be quite daunting to know where to start, but our team are here to help you choose the right bra for you.
Our friendly and knowledgeable team are on hand to help you find the best everyday bra that is comfortable and fits well, so give us a call on 01439 798388.
Elomi Cate Banded Bra - EL4030
The Cate banded bra really has stood the test of time, one of the longest standing ranges from Elomi and by the look of its popularity to this day it won’t be going anywhere soon. The cups come with a three section plus added side support for a forward projection with uplift and separation. The cups are finished with a sheer panel to the top with iconic arc embroidered detailing, which has been designed specially to minimiser see through. The cups are finished with light elastic edging for a smooth fit. The wings come with a power net that gives a great anchorage and support. Coming in continuity colours of latte, black, white, rosewood and hazel and come in a great range of sizes of 34 to 46 DD to K.
A best selling non wired bra in a back size 40 is the Rosa Faia Twin Non Wired Bra - Product Code 5493, a popular choice with customers, that Sally recommends as her new favorite non wired bra. This wireless bra has a slight stretch on the neck edge for a forgiving fit and is made from extremely soft comfortable fabric for confort all day. The Rosa Faia Twin Non Wired bra by Anita comes in 6 continuity colours - white, champagne, skintone, desert, rosewood and black in cup sizes A to F and back sizes 32 to 48. Anita's best selling non wired feel good bra, they claim every woman should have one in her underwear drawer! Take a look today!
Why We Love This Rosa Faia Twin Non Wired Bra
The features of this bra that makes this an excellent everyday bra include....
- A comfortable non wired feel good bra for all day comfort.
- Double layered for added comfort and a smooth look.
- Made from an extremely comfortable smooth silky, microfibre fabric.
- A slight stretch on the neck edge for a forgiving fit.
- Adjustable straps for ease of fit.
- Wide comfort straps to add extra comfort to your shoulders!
- E cup and above have reinforce straps for added support.
- This is a medium support bra.
- A seamless bra for a smooth appearance.
- A full cup bra to support the breasts.
Royce Cara Support Non Wired Bra - 1461
The Cara bra is fairly new addition to the Royce collection and one we think quite highly about. The bra gives a strong and full coverage support. The cups are non-wired and come with three sections plus side support, they are double layered which is made from cotton and mesh which helps give that added support while being kind to the skin. The deep firm under band is great for that added uplift and grounded support for all day comfort. Comin in a blush colour and ranging is sizes 32-42G to L cup.
Fantasie Reflect Underwired Side support Bra - FL101801
This very pretty bra from Fantasie has quickly become a new favourite with many of our customer. This bra comes with a wide wire which offers extra comfort for all day wear. The cups come with three section cups and added side support which come with a powerful stretch lace to the top of the cups which give a lovely modern shape. The straps are fully adjustable and have been designed with ‘peach skin’ which is soft yet supportive. The lace wing backs offers support and anchorage and leads on to a tow back which offers a centre pull straps to prevent the straps from sipping. In continuity colours of black, white and natural beige and comes in 30-42D to J.
PrimmaDonna Deauville Underwired Fuller Bust Full Cup Bra – 0161815
This bra is based on the long standing Deauville bra but has been based solely on the cups I, J and K. The deep three section cups with side panel provides a forward production and great support. This style of Deauville is made from a firmer fabric which provides all day support for those larger cups and comes with the famous Deauville embroidery to the top of the cups. The wide straps also support better anchorage and support for the bust for all day comfort. In colours black and caffe latte and in back sizes 32-44 I, J and K cups.
If you think it might be time for a new bra and fancy trying a new style or brand and not sure what size it is you need to try. Then don’t hesitate to contact us and the experts at Amplebosom can help advise on the size.
Bra Measuring and Fitting Advice
For additional advice and information on finding a well-fitting bra, visit our blog posts on:
- Bra Measuring Guide - advice on measuring your own bra size at home
- Bra Fitting Guide - hints and tips to make sure your bra fits correctly
- Bra Size Guide - guidance on sizing for the different brands we stock
- Bra Fitting Appointments - book a fitting appointment with us in North Yorkshire
Frequently Asked Bra Fitting & Sizing Questions:
- What Are Sister Bra Sizes?
- How Do I Measure My Bra Size At Home?
- How Do I Find A Comfortable Bra?
- What Are The Best Bra Brands For Big Busts?
- How Do I Find The Perfect Fitting Bra?
- How Do I Know If I’m Wearing The Right Size Bra?
- What Should I Expect At A Bra Fitting?
- When should I have a bra fitted?
- My breasts are not the same size. What should I do?
- What is the difference between UK, US and European bra sizes?
MEASURING GUIDE & BRA FITTING HELP
Check out our bra measuring guide to help you measure for a bra. Take time to measure yourself properly. If you would like help with measuring we can talk you through our guide to help you find your size, so give our friendly team a call on 01439 798388.
Visit our bra fitting guide which offers hints and tips for making sure your bra fits properly. Here you will also find answers to many of the most common bra fitting questions, as well as our collection of bra advice blogposts.
We offer bra fitting appointments here in North Yorkshire. Give us a call on 01439 798 388 and we can arrange a day for you. Our bra fitting specialists are here to help! Offering friendly and supportive advice to help you choose a well fitting and comfortable bra. Our team can help you to find the perfect fit from the wide range of bras and underwear we have available.
Whether you're in need of a complete wardrobe refresh and those comfortable everyday bras, or looking for something special for an upcoming occasion or holiday, we will have something to suit you, whatever your size and budget.
We are happy to advise about sizing and to give bra recommendations so please give us a call on 01439 798388. If you measure yourself and get your overbust and underbust measurement we can advise about your bra size and make specific bra recommendations for you from our collection of leading bra brands.
If you would like any help finding a well fitting and comfortable bra then please give our friendly team of bra specialists a call on 01439 798388 or email us here, we will be happy to help.
Also visit our bra fitting guide, our handy bra measuring guide, our useful size guide page with size charts for bras, briefs and nightwear and our blog for advice, tips and recommendations. We are here to help you find your perfect fit!
Our Facebook group is a place for you to ask questions and seek guidance from our team of bra specialists. We share our expertise for finding the perfect bra for you. Give answers to common bra fitting problems and share exclusive updates on new arrivals, latest trends and special offers. You can also chat with like-minded ladies and share your favourite styles and brands with one another.
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Blogpost last edited by Francesca 12/03/2025 and Sara 26/08/2025.