Enter height, weight, age, sex and activity level to get your Body Mass Index with its WHO category, the healthy weight range for your height, your basal metabolic rate (Mifflin–St Jeor), and the daily calorie targets to maintain, lose or gain weight.
BMI = weight ÷ height², with height in metres. It is a population screening number, not a body-composition measurement — muscular athletes often read "overweight" while carrying little fat. Several Asian populations use 24 / 28 as the overweight / obesity cutoffs instead of the WHO 25 / 30.
Frequently asked questions
Is BMI accurate for everyone?
No — it ignores muscle mass, bone density and fat distribution. It screens populations well but misreads athletes, and loses accuracy for children, pregnancy and adults over ~65.
What are the BMI categories?
WHO: underweight < 18.5, normal 18.5–24.9, overweight 25–29.9, obesity ≥ 30. China's WS/T 428 standard uses 24 / 28 for overweight / obesity.
How many calories to lose 0.5 kg per week?
About a 550 kcal daily deficit — 1 kg of body fat holds roughly 7,700 kcal. The page computes the target from your own TDEE.
中文说明
输入身高、体重、年龄、性别与活动水平，得到 BMI 及 WHO 分类、对应身高的健康体重范围、基础代谢率（Mifflin–St Jeor 公式）与维持、减重或增重的每日热量目标。
BMI = 体重 ÷ 身高²（身高以米计）。它是人群筛查指标而非体成分测量——肌肉发达的运动员常被误判为"超重"。中国等亚洲人群常用 24 / 28 作为超重/肥胖界值，而非 WHO 的 25 / 30。
常见问题
BMI 对所有人都准吗？
不——它不区分肌肉、骨密度与脂肪分布，用于人群筛查很好，但会误判运动员，对儿童、孕期和 65 岁以上人群也不够准。
BMI 的分类标准是什么？
WHO：偏瘦 < 18.5，正常 18.5–24.9，超重 25–29.9，肥胖 ≥ 30；中国 WS/T 428 标准则以 24 / 28 为超重/肥胖界值。
每周想减 0.5 公斤要少吃多少？
每天约 550 千卡的热量缺口——1 公斤体脂约含 7,700 千卡。页面会按你的 TDEE 直接算出目标值。