How to Measure Bra Size at Home Without a Fitting Room

By Blue Canoe |Wide Range of Fashionable and Organic | Published: 2026-10-16

Category: How-to Guides

Learn how to measure your underbust and bust at home, calculate your bra size, and use fit checks to find a bra that truly fits—no fitting room required.

Quick answer

To find your bra size at home, wear an unpadded bra, measure snugly around your ribcage for the underbust, then measure around the fullest part of your bust. Subtract underbust from bust to get cup size. Always verify with a fit check—sizes vary by brand, and a bra that feels comfortable and supportive is the right one.

Gather what you need

You'll need a soft measuring tape, a mirror, and a well-fitting unpadded bra (or no bra if you prefer). If you don't have a tape measure, use a string or ribbon and measure it against a ruler. Stand in front of a mirror to keep the tape level and parallel to the floor.

Measure your underbust

Wrap the tape around your ribcage, directly under your bust, keeping it snug but not tight. Breathe normally and round to the nearest whole inch. If you get an odd number, round down to the nearest even number for the band size. This measurement determines your band size.

Measure your bust

Wrap the tape around the fullest part of your bust, usually across the nipples. Keep the tape level and not too tight—it should rest gently against your skin. Round to the nearest whole inch. This is your bust measurement.

Calculate your cup size

Subtract your underbust measurement from your bust measurement. Each inch difference corresponds to a cup size: 1 inch = A, 2 inches = B, 3 inches = C, 4 inches = D, 5 inches = DD/E, and so on. For example, if your underbust is 34 and your bust is 37, you're a 34C.

Try on and adjust

Use your calculated size as a starting point, then try on bras from different brands. Sizes can vary, so you may need to adjust the band or cup. The band should be snug but not uncomfortable, and the center gore should lie flat against your sternum. If the band rides up, go down a band size and up a cup size. If the cups gap or wrinkle, try a smaller cup or different style.

Step-by-step bra measurement guide

1. Put on a comfortable, unpadded bra: Wear a bra that fits well but isn't padded, or go without if you prefer. This gives you the most accurate measurement. Checkpoint: The bra should not compress your bust or have push-up padding.
2. Measure your underbust: Wrap the tape snugly around your ribcage, directly under your bust. Keep it level and parallel to the floor. Round to the nearest whole inch, then round down to the nearest even number for band size. Common mistake: Measuring too loosely—the tape should feel snug but not restrictive.
3. Measure your bust: Wrap the tape around the fullest part of your bust, usually across the nipples. Keep it level and not too tight. Round to the nearest whole inch. Checkpoint: The tape should rest gently against your skin without indenting it.
4. Calculate your cup size: Subtract your underbust measurement from your bust measurement. Each inch difference equals one cup size: 1 inch = A, 2 inches = B, 3 inches = C, 4 inches = D, 5 inches = DD/E, and so on. Common mistake: Forgetting to round consistently—use the same rounding for both measurements.
5. Try on your calculated size: Use your size as a starting point and try on bras from different brands. Adjust as needed: if the band rides up, go down a band size and up a cup size; if cups gap, try a smaller cup. Next step: Check the fit—the band should be snug, the center gore flat, and the cups smooth.

Product facts

Yoga Bra: The Yoga Bra is made from an organic cotton/spandex blend that provides soft, comfortable support, with a wide fabric band that doesn't bind or dig in. A wide, non-binding band can be more forgiving if your underbust measurement falls between sizes, and the soft fabric is gentle on skin.
Triple Strap Active Bra: The Triple Strap Active Bra features crossing straps in back and a wide fabric band, made from soft organic cotton. The crossing straps add style and support for workouts or everyday wear, while the wide band helps distribute pressure for comfort.