The average size of a 40 year old woman varies based on factors like height, body frame, and body composition. However, research provides general guidelines on typical weights and clothing sizes for women in this age group. Understanding the average can help women evaluate their own size and health at 40.
Average Height and Weight
At age 40, the average woman is 5 feet 4 inches tall and weighs 142-145 pounds, according to Centers for Disease Control (CDC) data1. However, healthy weights can range widely depending on body frame size, which is determined by a person’s wrist circumference. The three main body frame categories are2:
- Small frame: wrist size under 5.5 inches, average healthy weight 109-127 pounds
- Medium frame: wrist size 5.5-5.75 inches, average healthy weight 114-141 pounds
- Large frame: wrist size over 5.75 inches, average healthy weight 126-163 pounds
Muscle mass and body fat percentage also impact ideal weights. Athletes and muscular builds generally weigh more than less active people with higher body fat for an equivalent height.
Average Body Mass Index (BMI)
Body mass index (BMI) uses height and weight to estimate body fat. The formula is:
BMI = (Weight in Pounds / (Height in inches x Height in inches)) x 703
A BMI of 18.5-24.9 is considered healthy for most adults. The CDC reports the average 40 year old American woman has a BMI of 28.6, which falls in the overweight range1. However, BMI has limitations in accurately estimating body fat, since it does not account for muscle mass or body frame size.
BMI Classifications for a 40 Year Old Woman
| BMI | Weight Status |
|---|---|
| Below 18.5 | Underweight |
| 18.5-24.9 | Healthy Weight |
| 25.0-29.9 | Overweight |
| 30.0-34.9 | Obese (Class 1) |
| 35.0-39.9 | Obese (Class 2) |
| 40.0 and above | Obese (Class 3) |
So while the average 40 year old woman may fall in the overweight BMI range, individuals can have a healthy BMI between 18.5 to just under 25. Maintaining a BMI in the ideal range has health benefits including reduced risk for type 2 diabetes, heart disease, and certain cancers3.
Average Waist Circumference
Along with BMI, waist circumference helps evaluate weight distribution and health risks. Carrying excess fat around the abdominal area is linked to metabolic abnormalities. The CDC reports the average waist circumference for a 40-59 year old woman in the U.S. is 39 inches4.
Healthy Waist Circumference Ranges for Women
| Waist Circumference | Health Risk |
|---|---|
| Under 35 inches | Low |
| 35-40 inches | Moderate |
| Over 40 inches | High |
Maintaining a waist circumference under 35 inches has the lowest risk for obesity-related health conditions like type 2 diabetes, hypertension, and cardiovascular disease5. Women with waists over 40 inches have a significantly elevated health risk.
Average Clothing Size
Due to vanity sizing and varying size charts among retailers, clothing sizes do not always reflect standard body measurements. However, looking at sales data provides insight into the average clothing size purchased by 40 year old women.
Average Clothing Sizes for 40 Year Old Women
| Clothing Type | Average Size Purchased |
|---|---|
| Dresses | 14 |
| Jeans | 14 |
| Yoga Pants | Large |
| Bras | 38C |
According to sales data aggregated across major U.S. retailers, the average 40 year old woman buys sizes 14 dresses and jeans, large yoga pants, and 38C bras. This aligns with a medium frame and BMI in the overweight range for the average woman6. However, there is wide variation among individuals in clothing sizes purchased. Body shape preferences, fitness levels, and height differences mean healthy 40 year old women may buy anything from size 4 to size 20+ clothing.
Changes in Size Over Time
On average, women gain about 1-2 pounds per year from age 40 onward. Gradual muscle loss and fat gain around the midsection occur over time, even with no change in diet or activity levels. However, staying physically active, eating a healthy diet, and maintaining muscle tone through strength training can help minimize weight gain as women go through perimenopause and menopause7. Areas women tend to notice size increases after 40 include8:
- Waist circumference
- Upper arms
- Bra band size
- Hips and buttocks
Along with weight gain, aging and hormonal shifts lead to changes in fat distribution as women enter their 40s. Factors like genetics, diet, lifestyle, and childbearing also affect how an individual woman’s body changes over time. While weight may increase slightly after 40, focusing on whole body health and fitness can keep women feeling and looking their best.
Ideal Size vs. Healthy Size
At age 40, the average woman in the U.S. wears a size 14 and has a BMI in the overweight range. However, ideal health indicators like BMI and waist circumference have a wide healthy range depending on body frame size and muscle mass. The most important focus is maintaining overall health through diet and exercise rather than fixating on weight or dress size. A healthy, fit size 12 woman who eats well and exercises regularly may actually be at lower risk for obesity-related diseases than an inactive size 2 woman with poor nutrition. Good health looks different for every individual.
Conclusion
While average sizing data provides a general guideline, there is no one ideal weight or body size for 40 year old women. The healthiest size maximizes fitness while keeping BMI, waist circumference, and body fat percentage within recommended ranges. Rather than focusing on arbitrary size numbers, the most important factors are supporting health and wellness by eating a nutritious diet, staying active, managing stress, and getting health screenings. Maintaining good lifestyle habits is the best way for women to feel and look their personal best at age 40 and beyond.
