BMI Calculator

Calculate your Body Mass Index and track your health

ages: 2 - 120
feetinches
pounds

Result

23
(Normal)
Enter your details and click Calculate to see your BMI result

什麼是BMI？

身體質量指數（BMI）是一種廣泛使用的篩查工具，用於計算您的體重相對於身高是否健康。BMI由比利時數學家阿道夫·凱特勒在19世紀30年代開發，已成為評估成人體重類別的全球標準。我們的BMI計算機為女性、男性和兒童提供準確的結果，無論您使用的是英國、澳洲還是加拿大的BMI計算機標準。

BMI公式得到了包括NHS BMI計算機、CDC BMI計算機、WHO和全球醫療機構在內的主要健康組織的普遍認可。醫療專業人士使用BMI作為初步篩查工具來識別潛在的體重相關健康風險。雖然BMI不能直接測量體脂肪，但對大多數人來說，它與更直接的體脂肪測量方法有很好的相關性。

我們的線上BMI計算機支持多種測量系統，並提供帶有詳細健康類別說明的即時結果。無論您需要女性BMI計算機、男性BMI計算機還是兒童BMI計算機，我們的工具都會根據既定的醫療指南提供適合年齡和性別的指導。

BMI公式和計算方法

BMI計算公式很簡單：BMI = 體重（公斤）/ 身高（公尺）²。對於使用英制單位的用戶，公式變為：BMI = 體重（磅）/ 身高（英寸）² × 703。我們的身體質量指數計算機自動處理公制（公分和公斤）和英制單位（英尺/英寸和磅），無論您偏好哪種測量系統都能輕鬆計算BMI。

計算過程包括幾個步驟：首先，如果使用公制單位，將身高轉換為公尺（公分除以100），然後將身高值平方，最後用體重除以身高的平方。對於英制測量，額外乘以703將結果轉換為匹配公制BMI量表。這種標準化確保BMI值在全球範圍內保持一致。

BMI計算範例：

Metric: BMI = weight (kg) / height (m)²
Example: 70 kg / (1.75 m)² = 22.86
Imperial: BMI = weight (lb) / height (in)² × 703
Example: 154 lb / (69 in)² × 703 = 22.71

像我們的工具這樣的高級BMI計算機還考慮了兒科計算的年齡等因素，並為解釋提供額外的背景資訊。BMI指數計算在全球範圍內保持不變，但解釋可能會根據種族、年齡和不同國家衛生系統使用的特定健康指南而略有不同。

BMI量表和範圍

BMI量表將體重狀態分為四個主要類別，每個類別都與不同的健康風險相關。了解這些BMI範圍有助於您解釋結果並就健康做出明智決定。正常BMI範圍（18.5-24.9）與體重相關健康問題的最低風險相關，而肥胖BMI水平（30+）顯著增加健康風險。

BMI類別BMI範圍描述健康風險
體重過輕< 18.5低於正常BMI營養缺乏、骨質疏鬆
正常BMI18.5 - 24.9健康BMI範圍慢性疾病風險最低
過重25.0 - 29.9高於正常BMI糖尿病、高血壓風險增加
肥胖BMI≥ 30.0高健康風險心臟病、中風、糖尿病高風險

關於BMI範圍的重要說明：

  • 女性和男性BMI計算機的BMI範圍相同
  • 兒童BMI計算機使用不同的百分位數範圍
  • 理想BMI根據年齡、種族和個人健康因素略有不同
  • 運動員可能因肌肉量而BMI高但仍然健康

不同群體的BMI計算機

雖然基本BMI公式在不同人群中保持一致，但解釋和應用可能會根據年齡、性別、種族和特定健康狀況而有所不同。了解這些差異有助於確保更準確的健康評估和適當的醫療指導。

女性BMI計算機

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男性BMI計算機

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兒童BMI計算機和兒科評估

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老年人和特殊人群BMI計算機

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如何計算BMI：分步指南

使用我們的線上BMI計算機計算BMI很簡單。無論您偏好公制還是英制單位，我們的工具都會自動處理轉換。按照這些簡單步驟獲取準確的BMI結果並了解它們對您健康的意義。

使用我們的BMI計算機

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手動BMI計算

公制單位（kg/m²）：

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英制單位（lb/in²）：

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準確BMI測量技巧

身高測量：

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體重測量：

  • BMICalculator.weightTip1
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重要說明： 此BMI計算機專為成人（20歲以上）設計。對於兒童和青少年，請使用考慮年齡和性別百分位數的專業兒科BMI計算機。孕婦應諮詢醫療保健提供者以獲取適當的體重評估工具。

BMI Prime

BMI prime is the ratio of a person's measured BMI to the upper limit of BMI that is considered "normal," by institutions such as the WHO and the CDC. This upper limit is 25 kg/m².

BMI Prime Formula:

BMI Prime = BMI / 25
ClassificationBMIBMI Prime
Severe Thinness< 16< 0.64
Moderate Thinness16 - 170.64 - 0.68
Mild Thinness17 - 18.50.68 - 0.74
Normal18.5 - 250.74 - 1
Overweight25 - 301 - 1.2
Obese Class I30 - 351.2 - 1.4
Obese Class II35 - 401.4 - 1.6
Obese Class III> 40> 1.6

BMI prime allows us to make a quick assessment of how much a person's BMI differs from the upper limit of BMI that is considered normal. It also allows for comparisons between groups of people who have different upper BMI limits.

Ponderal Index

The Ponderal Index (PI) is similar to BMI in that it measures the leanness or corpulence of a person based on their height and weight. The main difference between the PI and BMI is the cubing rather than squaring of the height in the formula.

US Units:

PI = height (in) / ∛mass (lbs)
Example: 70 / ∛160 = 12.9

Metric Units:

PI = mass (kg) / height³ (m)
Example: 72.57 / 1.778³ = 12.9

While BMI can be a useful tool when considering large populations, it is not reliable for determining leanness or corpulence in individuals. The PI is more reliable for use with very tall or short individuals, while BMI tends to record uncharacteristically high or low body fat levels for those on the extreme ends of the height and weight spectrum.

Health Risks

Risks of Being Overweight

Being overweight increases the risk of serious diseases and health conditions:

  • High blood pressure
  • Higher levels of LDL cholesterol ("bad cholesterol")
  • Type II diabetes
  • Coronary heart disease
  • Stroke
  • Gallbladder disease
  • Osteoarthritis
  • Sleep apnea and breathing problems
  • Certain cancers (endometrial, breast, colon, kidney, gallbladder, liver)
  • Mental illnesses such as clinical depression and anxiety
  • Generally increased risk of mortality

Risks of Being Underweight

Being underweight also has associated health risks:

  • Malnutrition, vitamin deficiencies, anemia
  • Osteoporosis (bone weakness)
  • Decreased immune function
  • Growth and development issues in children and teenagers
  • Reproductive issues for women due to hormonal imbalances
  • Higher chance of miscarriage in first trimester
  • Potential complications during surgery
  • Generally increased risk of mortality

In some cases, being underweight can be a sign of underlying conditions such as anorexia nervosa. Consult your doctor if you think you or someone you know is underweight.

Limitations of BMI

Although BMI is a widely used and useful indicator of healthy body weight, it does have its limitations. BMI is only an estimate that cannot take body composition into account.

In Adults:

  • BMI measures excess body weight, not excess body fat
  • Influenced by age, sex, ethnicity, muscle mass, body fat, and activity level
  • Older adults tend to have more body fat than younger adults with the same BMI
  • Women tend to have more body fat than men for an equivalent BMI
  • Muscular individuals and athletes may have higher BMIs due to muscle mass

In Children and Adolescents:

  • Height and sexual maturation can influence BMI and body fat
  • BMI is better for obese children than overweight children
  • In thin children, BMI differences can be due to fat-free mass
  • Same adult limitations apply to children and adolescents

Important: BMI is fairly indicative of body fat for 90-95% of the population, and can effectively be used along with other measures to help determine an individual's healthy body weight.

常見問題（FAQ）

什麼是正常BMI？

BMICalculator.faqNormalBmiAnswer

BMI計算機有多準確？

BMICalculator.faqAccuracyAnswer

我可以為兒童使用此BMI計算機嗎？

BMICalculator.faqChildrenAnswer

公制和英制BMI計算有什麼區別？

BMICalculator.faqUnitsAnswer

什麼時候應該就BMI問題看醫生？

BMICalculator.faqDoctorAnswer

我應該多久檢查一次BMI？

BMICalculator.faqFrequencyAnswer

男性和女性的BMI不同嗎？

BMICalculator.faqGenderAnswer

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