How to Measure Your Bra Size During Pregnancy

One of the most common surprises during pregnancy is how quickly your bra size changes. Most women go up 1–2 cup sizes and even a band size during pregnancy — and getting the right fit is essential for comfort and breast health.

Why Bra Size Changes During Pregnancy

As your body prepares for breastfeeding, your breast tissue grows and your ribcage expands. This typically happens in two main phases: the first trimester (initial growth) and the third trimester (as milk production begins). Many women find they need to be re-measured every 4–6 weeks.

What You'll Need

• A soft measuring tape
• A well-fitting non-padded bra or no bra at all
• A mirror or a friend to help

Step-by-Step: How to Measure at Home

Step 1: Measure Your Band Size

Wrap the measuring tape snugly around your ribcage, just below your bust. Keep it level and breathe normally. Round to the nearest whole number. If the number is even, that's your band size. If it's odd, add 1.

Step 2: Measure Your Bust Size

Wrap the tape loosely around the fullest part of your chest (across your nipples). Keep it parallel to the ground. Round to the nearest whole number.

Step 3: Calculate Your Cup Size

Subtract your band size from your bust measurement. Each inch difference corresponds to a cup size:

• 1 inch = A cup
• 2 inches = B cup
• 3 inches = C cup
• 4 inches = D cup
• 5 inches = DD/E cup

Tips for a Good Fit

• The band should feel snug but not tight — you should be able to fit two fingers underneath
• The underwire (if any) should sit flat against your ribcage, not on breast tissue
• Cups should contain all breast tissue with no spillage or gaps
• Straps should not dig in or slip off

When to Get Re-Measured

We recommend getting measured at the start of each trimester and again around 36 weeks as your body prepares for milk production. After delivery, wait 6–8 weeks before investing in a full set of nursing bras.

Shop Maternity & Nursing Bras in Your Size

Once you know your size, find your perfect fit in our maternity bra collection — designed for growing bodies with adjustable fits and soft, supportive fabrics.

Planning ahead for breastfeeding? Browse our nursing bras too, so you're ready from day one.