What’s the Average Bra Size for Your Age?
Quick Summary
Average bra sizes tend to shift with age: roughly 32A–34B in the teen years, B–D cups in your 20s, 36–38 band with C–D cups in your 30s, and 36–40 band with D–DD cups in your 40s and 50s.
Whether you’re a teen just starting to wear a bra or someone who’s been wearing bras for years, you may be curious about what the average bra size is by age. After all, bra size is more than simply a number; it represents how the body changes throughout a person’s life. While there may not be a universal answer to this question, having a general idea of what’s typical at different ages can help you better understand your own body’s journey.
In this guide, we’ll examine how to determine your own bra size, explore the average bra size by age, and discuss why “average” doesn’t matter when it comes to finding the perfect fit.
How To Determine Your Bra Size
Before discussing the average bra size by age, let’s make sure you know how to measure yourself correctly. You’ll need a soft measuring tape for this.
Measure Bust
Stand straight, wearing an unpadded bra. Wrap the measuring tape around the fullest part of your bust, keeping the tape parallel to the ground. The number you get is your bust measurement.
Calculate Band Size
Next, measure around your ribcage just below your bust. Add 2 inches for even or 3 if you get an odd number to get your band size.
Find Cup Size
Now, subtract your band measurement from your bust measurement. Each extra inch of difference is a cup size, starting with a 1-inch difference as an A.
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Average Bra Size by Age Group
Teens (13-19 years)
During puberty, breast development can vary widely. However, most girls wear sizes ranging from 32A to 34B.
20’s
By their 20s, many women have found a more stable bra size, often ranging from B to D cups. At this age, lifestyle changes or pregnancy can often impact breast size.
30’s
For women in their 30s, average sizes are typically in the 36-38 band sizes with C-D cups, though again, this varies.
40’s & 50’s
In the 40s and 50s, hormonal changes from perimenopause and menopause can cause shifts in breast size. Most women experience an increase in breast size due to weight gain during menopause. At this age, the average bra size may shift to a band size of 36-40 with D to DD cups.
How Breast Size Can Change Over Time
Breast size isn't static. The most significant influences are: (1) Pregnancy and hormonal changes — breasts often increase in size, then reduce after breastfeeding. (2) Weight fluctuation. (3) Aging, including hormonal shifts during menopause.
Why “Average” Bra Size Doesn’t Always Matter
Here’s the truth: While it’s informative to have a bra size chart by age, these numbers shouldn’t dictate how you feel about your body. Thirdlove is committed to size inclusivity, ensuring that every woman can find her perfect fit, regardless of whether her size aligns with the average. Whether you wear a 32B, a 40G, or something in between, we’ve got you covered.
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How to Find Your Perfect Bra Fit
It is easy to determine your ideal size from the comfort of your home! Follow the steps to measure yourself, or try Thirdlove’s Fit Finder® quiz to skip measuring tape and find a tailored fit based on your preferences and needs. The quiz considers everything, from your body to how you like your bra to fit.
FAQs
Does bra size change with age? Yes - pregnancy, hormonal changes, weight fluctuation, and aging can all affect breast size over time, including a common increase during perimenopause and menopause.
Why doesn't "average" bra size matter? Because averages are just a general reference point, not a target. Thirdlove is committed to size inclusivity, so whether your size matches the average for your age or not, the goal is finding your own perfect fit.
How do I calculate my bra size at home? Measure your bust at its fullest point, measure your ribcage just below your bust for your band size, then subtract the band measurement from the bust measurement — each inch of difference corresponds to a cup size, starting at a 1-inch difference for an A cup.
What causes breast size to increase in your 40s and 50s? Hormonal changes from perimenopause and menopause, along with related weight gain, are common causes of breast size changes at this age.
Is there a faster way to find my size than measuring? Yes - Thirdlove's Fit Finder® Quiz can estimate a tailored size and fit based on your preferences and needs without a measuring tape.
Last updated September 30, 2026
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