Red marks on your skin. A band that rides up your back. That nagging sense that a bra just never sits right. Most of the time, the culprit is the size, and a soft measuring tape plus five minutes at home is enough to sort it out.
Most women are wearing the wrong bra size, and it's usually not for lack of trying. Sizing jumps around from brand to brand, the fit labels don't always mean what you'd expect, and guessing in a fitting room only tells you so much. So here's how to measure your band and bust at home, read a bra size chart to land on your correct bra size, and turn those numbers into a well-fitting bra. No specialist needed, and no more throwing out ill-fitting bras.
Table of Contents
- Why Bra Cup Size Charts Matter
- What You Need Before You Measure
- How to Measure Your Bra Size at Home
- How to Read a Bra Cup Size Chart
- What to Do When You’re Between Sizes
- Shop Felina Bras by Your Size
Why Bra Cup Size Charts Matter
You've probably bought a bra that looked right on paper and felt wrong the second you put it on. A bra size chart is what stops that from happening again. Instead of estimating or reaching for whatever you've always bought, it ties your real measurements to a size you can trust.
Wear the wrong size and the problems are real: underwire that digs in, bra straps that slip, cups that gap, and support that just isn't there when you've been on your feet all day. Cup sizing doesn't work the same everywhere either. It shifts between brands and changes a lot across regions, so a 34C in one label can fit nothing like a 34C in another. The bra size chart cuts through that mess and gives you a solid place to start, wherever you happen to be shopping.
What You Need Before You Measure
You don't need a fitting room or any special gear to get an accurate size. The whole thing takes a few minutes. Get the setup right, and your numbers will actually mean something when you shop.
Grab a soft measuring tape, because that's the one tool that matters here. A rigid ruler or a length of string won't give you a reliable read, and a fabric tape measure works fine as long as it doesn't stretch. Wear a non-padded bra (or nothing at all), since padding adds bulk and skews both your band and bust measurements. And measure on an exhale, when your body's relaxed, so you get a true number instead of one that moves with your posture.
How to Measure Your Bra Size at Home
Two quick measurements and a bit of simple subtraction. That's the whole process. Here's how it goes.
Finding Your Band Size
Wrap the tape snugly around your rib cage, right under your bust, and let it fit snugly against your skin. Firm, but not so tight that it's uncomfortable. This underbust measurement is the basis for your bra band size. Take that number and round it to the nearest even number, and there's your band size.
Finding Your Bust Measurement
Now measure loosely around the fullest part of your chest to capture your bust size. Don't pull the tape tight here. Keep it parallel to the floor the whole way around so both sides read evenly.
Calculating Your Cup Size
Subtract your band measurement from your bust measurement. The gap between them is what points to your cup size, tying your band and cup size together. Roughly speaking, each inch of difference is one cup size up, so a one-inch difference lands you at an A, two inches at a B, and up from there.
How Do You Read a Bra Cup Size Chart?
A bra size chart does one thing. It takes your two measurements, band and bust, and turns the difference between them into a cup letter. A bigger difference means larger cup sizes. Here's the quick reference:
- Less than 1-inch difference: AA cup
- 1 inch: A cup
- 2 inches: B cup
- 3 inches: C cup
- 4 inches: D cup
- 5 inches: DD or E cup
- 6 inches: DDD or F cup
- 7 inches: G cup
- 8 inches or more: G+ or H cup
Here's something a lot of people miss. Cup size isn't fixed on its own. A 34C and a 36C aren't the same cup volume because the cup scales with the band. That's why a 34D and a 36C actually hold a similar amount, even though the letters don't match.
Shopping across regions and different countries? Keep the conversions handy. UK sizes and European bra sizes don't line up with US sizing one-to-one: a US 34D is a UK 34D, an EU 75D, and a FR 90D. The cup letter often stays put, but the band number changes with the system, so check the brand's own bra size chart before you order from abroad.
What to Do When You're Between Sizes
Landing between sizes happens more than you'd think, and it doesn't leave you stuck. A couple of small adjustments can dial in the fit without sending you back to square one.
Sister Sizing Explained
Sister sizing shifts the band and cup together, so the bra feels different on your body while holding the same overall volume. Want a looser feel? Go up one band size and down one cup. Want it snugger? Go down one band and up one cup. Say you measure as a 36C, but the band feels too loose. Try a 34D instead.
Signs Your Current Bra Doesn't Fit
Your bra usually tells you exactly what's wrong. Cups that gap and pull away from your breast mean the cup's too large. Spillage over the top or underwire that lifts off your body means you need to size up. And a band that creeps up your back over the course of the day is a loose band, plain and simple. It should sit level and firm the whole way around.
Shop Felina Bras by Your Size
You've got your measurements, so put them to work. Felina lets you shop straight by size, which means you skip the guesswork and go right to styles built for your body.
Use the size-filtered product pages to browse bras in your exact band and cup combination, instead of scrolling past styles that were never going to fit. The collection runs from 32A through 44H, so whether you're a standard size or need extended sizing for a fuller bust, there's plenty worth trying, including fan favorites like Utopia, Celestial, and Versafit. Once you're in your size range, try a few different cuts. A T-shirt bra, a plunge, and a wireless option can each fit the same measurement differently depending on how they're built, and the one that feels best is the right one. Free and easy returns mean there's no risk in ordering two or three at once.
So that's it. Your band measurement, your bust measurement, and a clear read on how those two numbers become a cup size that works for you. A good fit feels supportive without digging in and secure without squeezing, comfortable enough that you forget it's there.
Ready to put your measurements to work? Explore Felina's collection and shop by your size.
Bra Cup Size Chart FAQs
How do I measure my bra cup size at home?
To measure your bra cup size at home, use a soft measuring tape. Subtract the band measurement from the bust measurement to estimate your cup size using a bra cup size chart.
What is a bra cup size chart?
A bra cup size chart shows how the difference between your bust and band measurements translates into cup sizes, such as A, B, C, or D.
How do I know if my bra cup size is wrong?
Your bra cup size may be wrong if your cups gape, spill over, wrinkle, or dig into your breast tissue. A properly fitting bra should fully contain your bust without gaps or overflow.
How often should I measure my bra size?
You should measure your bra size at least once or twice a year, or whenever your body changes due to weight fluctuations, pregnancy, breastfeeding, hormones, or lifestyle shifts. Using a bra cup size chart regularly can help you stay comfortable and choose bras that support your current shape.