What is BMI for women?
BMI is your weight divided by your height squared. It is a quick screening number, not a diagnosis. The formula is the same for women and men, but women usually carry more body fat at the same BMI, so it is best read together with waist size and overall health.
BMI categories for adult women
Under 18.5 is underweight, 18.5 to 24.9 is a healthy range, 25 to 29.9 is overweight, and 30 or more is obese. These WHO cut-offs apply to women from 18 up, whatever the age.
BMI by age: what changes?
Teens (under 18): BMI is compared with growth charts for age, not adult cut-offs.
20s to 40s: standard ranges apply. Pregnancy and breastfeeding change weight, so use pre-pregnancy numbers.
50s (menopause): hormonal shifts often move weight to the waist, so measure your waist too.
65 and over: a little extra weight can protect against frailty, and many doctors accept a BMI of about 23 to 30.
Limits of BMI
BMI ignores muscle mass, bone density and where fat sits. A strong, athletic woman may read as overweight while being healthy. A waist above 80 cm (31.5 in) is a useful extra warning sign.
What to do with your result
Treat the number as a starting point. Balanced meals, regular movement, good sleep and routine check-ups matter more than chasing a figure. Talk to your doctor before making big changes.
Frequently asked questions
Is the BMI formula different for women?
No, the formula is the same, but results should be read alongside body fat, waist size and age.
What is a healthy BMI for a woman?
For adult women, 18.5 to 24.9 is the standard healthy range.
Does BMI change with age?
The cut-offs do not change for adults, but doctors often accept a slightly higher BMI after 65.