A BMI between 18.5 and 24.9 is considered healthy for most adults. Below 18.5 is underweight; 25–29.9 is overweight; 30 and above is classified as obese.

BMI is a ratio of weight to height squared. It cannot distinguish between muscle and fat, so very muscular individuals may show an elevated BMI despite low body fat. Pair BMI with a body fat calculator for a more complete picture.

Every 4–8 weeks is reasonable if you are actively working toward a weight goal. Weekly tracking can create unnecessary anxiety since short-term fluctuations reflect water, not tissue changes.

Research suggests lower health-risk thresholds for people of Asian descent (overweight: ≥23, obese: ≥27.5). Discuss ethnicity-adjusted cutoffs with your healthcare provider if relevant.