Holding a soft measuring tape horizontally, pull it all the way around the body at the fullest part of the chest.

Grab a string (or even a shoelace), a pen and a ruler. Pull the string around the chest horizontally at the fullest part—similar to using a measuring tape—and use the pen to mark where one end of the string meets the other side. Then, lay the string on a flat surface and use a ruler to determine the chest measurement.

Use the chest measurement from steps 1 or 2 to find the bra size on the chart at the top of the screen. If the measurement falls between sizes on the chart, opt for the larger size—a slightly larger bra will be more comfortable than a bra that's too tight.
*Extended size (+) sports bras differ only in circumference, not length or style.

You should be able to fit two fingers between the strap and your body. If it's too loose, try a smaller size. If it feels or looks like it's digging into the shoulders, go up a size.

Make sure the band isn't too tight—two fingers should fit comfortably between the band and the body. Also, raise arms over the head to make sure the band doesn't ride up—it should fit straight across the ribs.

Go ahead … jump! There should be minimal bounce in the chest area when jumping, and the chest should feel covered and secure. If it's feeling too bouncy to move around comfortably, try a women's size.

For an everyday bra, a thin-strapped, lightweight design is perfect. These all-day, ultra-comfy bras offer complete coverage with a barely-there feel.
• Nike Trophy Bra
• Nike Indy Bra

For more intense activities like football or running, thick fabrics and wider bands deliver a held-in, super-snug fit and feel.
• Nike Swoosh Bra

Feeling like girls' bras aren't providing complete support? Check out the women's size guide—a women's bra may provide a better fit.