How to Measure Bra Size

Step-by-step guide on how to measure your bra size at home. Learn the correct technique for measuring underbust and bust for accurate results.

How to Measure Your Bra Size at Home

Measuring your bra size at home is simple and takes just a few minutes. All you need is a soft measuring tape (or a string and ruler). Follow these steps for the most accurate results.

What You’ll Need

  • A soft, flexible measuring tape
  • A mirror (helpful but optional)
  • Wear a non-padded bra or no bra

Step 1: Measure Your Band Size (Underbust)

Stand up straight with your arms at your sides. Wrap the measuring tape around your ribcage, directly under your breasts. The tape should be:

  • Snug but not tight — you should be able to fit one finger underneath
  • Level all the way around your body
  • Parallel to the floor

Round to the nearest whole number. If it’s an odd number, round up to the nearest even number. This is your band size.

Step 2: Measure Your Bust Size

Wrap the tape around the fullest part of your bust (usually at nipple level). The tape should be:

  • Not too tight — don’t compress breast tissue
  • Level and parallel to the floor
  • Positioned at the fullest point of your bust

Step 3: Calculate Your Cup Size

Subtract your band measurement from your bust measurement. The difference determines your cup size:

Difference Cup Size
Less than 1 inch AA
1 inch A
2 inches B
3 inches C
4 inches D
5 inches DD/E
6 inches DDD/F
7 inches G

Tips for Accurate Measurements

  • Measure at the right time: Avoid measuring just before your period when breasts may be swollen
  • Stand straight: Good posture ensures accurate measurements
  • Don’t hold your breath: Breathe normally while measuring
  • Measure twice: Take measurements twice to confirm accuracy
  • Try the leaning method: For more accurate bust measurements, lean forward at a 90-degree angle

Use Our Free Calculator

Now that you have your measurements, enter them into our Bra Size Calculator to get your size in US, UK, EU, and other international sizing systems. The calculator also provides sister size recommendations.