How to Measure a Bra Size for Girls and Teens
A girl or teen's bra size is found the same way an adult's is: measure the rib cage directly under the bust for band size, then measure the fullest part of the bust and subtract the band number to find the cup size. Age does not determine bra size — body proportion does, and teens can fall anywhere across the full range of band and cup sizes.
Step 1: Measure the Band
Wrap a soft measuring tape around the rib cage, directly under the bust, keeping it level and snug but not tight. Round to the nearest even whole number for the band size.
Step 2: Measure the Bust
Wrap the tape around the fullest part of the bust, parallel to the floor. Round to the nearest whole number.
Step 3: Subtract for Cup Size
Subtract the band number from the bust number. Each inch of difference is one cup size, starting at A: 1 inch = A, 2 inches = B, 3 inches = C, 4 inches = D, 5 inches = DD/E, 6 inches = DDD/F.
Why Age Is Not a Reliable Guide
A 13-year-old and a 17-year-old can both measure a 28D, or a 32A, or anywhere else on the chart — body development varies enormously, and there is no single size that fits a particular age. Comparing sizes to siblings, cousins, or friends can create unnecessary pressure; the measurements are the only reliable guide.
Choosing a First Bra or a New Size
For a first bra, a soft, unpadded bralette or a cami bra top is often the easiest starting point. For teens who need more coverage or support, an everyday bra with a back closure and adjustable straps allows more precise fit adjustment as the body continues to change.
Signs a Size Needs Adjusting
The same signs apply at any age: a band that rides up means it is too loose, straps that dig in usually mean the band (not the strap) needs adjusting, and cups that gap or spill mean the cup size needs to change. See signs of the wrong bra size for the full list.
Re-Measuring as Bodies Change
Growth during the teen years can be fast, so re-measuring every few months, or whenever a bra starts to feel off, is more useful than relying on last year's size.
Frequently Asked Questions
Does bra size depend on age?
No. Bra size depends on body measurements, not age. Teens of the same age can measure very differently, and the same teen's size can change repeatedly during growth.
What is a good first bra for a tween or young teen?
A soft, unpadded bralette or a cami bra top is often the most comfortable starting point, since both offer light coverage without heavy structure.
How often should a teen's bra size be re-measured?
Every few months during active growth, or any time a bra starts riding up, digging in, or otherwise feeling wrong.
Should a teen size up to a bigger band to grow into?
No. A band that is too big cannot provide proper support and tends to cause the same digging-strap, riding-up problems as any other ill-fitting band. Re-measure and size up only when actual growth requires it.
Use BRABAR's Fit Guide and Bra Size Calculator, and browse bras for tweens and bras for teens built around real measurements, not age brackets.
