⚖️ Free BMI Calculator

Calculate your Body Mass Index instantly to understand your weight status and get personalized health recommendations. Trusted by millions for accurate health assessments.

Enter Your Measurements

Your Results

22.9
Your BMI
Normal Weight
Underweight
<18.5 Normal
18.5-24.9 Overweight
25-29.9 Obese
30+
Healthy Weight Range 56.7 - 76.5 kg
Weight to Lose/Gain You're in healthy range!
BMI Prime 0.92
Ponderal Index 13.1

What is BMI (Body Mass Index)?

Body Mass Index (BMI) is a widely used measurement that helps assess whether a person has a healthy body weight relative to their height. Developed by Belgian mathematician Adolphe Quetelet in the 1830s, BMI has become one of the most common tools for evaluating weight status in adults.

How is BMI Calculated?

BMI is calculated by dividing your weight in kilograms by your height in meters squared:

BMI = Weight (kg) × Height× (m×)

For example, a person who weighs 70 kg and is 1.75 m tall would have a BMI of: 70 × (1.75 × 1.75) = 22.9

BMI Categories

The World Health Organization (WHO) classifies BMI into the following categories:

BMI Range Category Health Risk
Below 18.5 Underweight Malnutrition risk
18.5 - 24.9 Normal weight Low risk
25.0 - 29.9 Overweight Increased risk
30.0 - 34.9 Obese Class I High risk
35.0 - 39.9 Obese Class II Very high risk
40.0+ Obese Class III Extremely high risk

Important Limitations of BMI

BMI doesn't distinguish between muscle and fat mass. Athletes and muscular individuals may have a high BMI despite being healthy. BMI also doesn't account for fat distribution, age, gender, or ethnicity. Always consult a healthcare provider for a complete health assessment.

❤️ Health Risks Associated with BMI

Underweight (BMI < 18.5)

Being underweight can increase your risk of:

Overweight (BMI 25-29.9)

Carrying extra weight can lead to:

Obese (BMI 30+)

Obesity significantly increases the risk of:

How to Reach and Maintain a Healthy BMI

For Weight Loss (If Overweight/Obese)

  1. Create a calorie deficit: Consume 500-750 fewer calories daily for 1-1.5 lbs/week loss
  2. Increase physical activity: Aim for 150-300 minutes of moderate exercise weekly
  3. Eat more protein: Helps preserve muscle mass and increase satiety
  4. Reduce processed foods: Focus on whole foods, vegetables, and lean proteins
  5. Stay hydrated: Drink water before meals to reduce calorie intake
  6. Get adequate sleep: Poor sleep affects hormones that regulate hunger
  7. Manage stress: Chronic stress can lead to emotional eating

For Weight Gain (If Underweight)

  1. Eat more frequently: 5-6 smaller meals instead of 3 large ones
  2. Choose nutrient-dense foods: Nuts, avocados, whole grains, lean meats
  3. Add healthy fats: Olive oil, nut butters, fatty fish
  4. Strength training: Build muscle mass, not just fat
  5. Drink calories: Smoothies and shakes can add extra nutrition
  6. Rule out medical conditions: Some conditions cause unintentional weight loss

Sustainable Changes Win

Crash diets and extreme measures rarely work long-term. Focus on sustainable lifestyle changes you can maintain. A loss or gain of 0.5-2 lbs per week is considered healthy and sustainable.

BMI Alternatives and Complementary Measurements

While BMI is useful for population-level assessments, several other measurements provide additional insight into your health:

Waist Circumference

Measures abdominal fat, which is more dangerous than fat stored elsewhere. Risk increases with:

Waist-to-Hip Ratio (WHR)

Divide your waist measurement by your hip measurement. Health risk increases with:

Body Fat Percentage

A more accurate measure of body composition than BMI. Healthy ranges vary by age and gender, but generally:

Waist-to-Height Ratio

Your waist circumference should be less than half your height. Simple rule: Keep your waist circumference to less than half your height.

Complete BMI Reference Table: Weight Status by Height

Use this quick-reference table to find the healthy weight range for your height, based on WHO and CDC BMI classifications (BMI 18.5×24.9 = Normal weight):

Height Underweight
BMI <18.5		 Normal Weight
BMI 18.5×24.9		 Overweight
BMI 25×29.9		 Obese
BMI 30+
5'0" (152cm)Below 95 lbs95×127 lbs128×152 lbs153+ lbs
5'2" (157cm)Below 101 lbs101×135 lbs136×163 lbs164+ lbs
5'4" (163cm)Below 108 lbs108×144 lbs145×173 lbs174+ lbs
5'6" (168cm)Below 114 lbs115×154 lbs155×184 lbs185+ lbs
5'8" (173cm)Below 121 lbs122×163 lbs164×196 lbs197+ lbs
5'10" (178cm)Below 129 lbs129×173 lbs174×208 lbs209+ lbs
6'0" (183cm)Below 136 lbs137×183 lbs184×220 lbs221+ lbs
6'2" (188cm)Below 144 lbs145×194 lbs195×233 lbs234+ lbs
6'4" (193cm)Below 152 lbs153×204 lbs205×246 lbs247+ lbs
BMI Limitations to Know: BMI doesn't distinguish between muscle and fat. A muscular 6'0" / 200 lb athlete may have BMI 27.1 (overweight) but have only 12% body fat. Conversely, a sedentary person with BMI 24 may have 32% body fat (obese by body fat standards). Always combine BMI with waist circumference (healthy: <40" men / <35" women) and body fat percentage for a complete picture.

💡 Real-World Examples & Use Cases

BMI estimates body-weight category from height and weight. Here are three worked examples.

5'10" (178 cm), 180 lb (82 kg)

An adult who is 5 feet 10 inches tall and weighs 180 pounds.

Result: BMI ≈ 25.9 — at the top of the ‘normal’ range, just below the overweight cutoff of 25.

5'4" (163 cm), 130 lb (59 kg)

An adult who is 5 feet 4 inches tall and weighs 130 pounds.

Result: BMI ≈ 22.2 — squarely in the healthy-weight range (18.5–24.9).

6'2" (188 cm), 220 lb (100 kg)

An adult who is 6 feet 2 inches tall and weighs 220 pounds.

Result: BMI ≈ 28.3 — in the overweight range; pair BMI with waist size and body-fat % for a fuller picture.

🔍 People Also Ask

Is BMI accurate for athletes?

Not always. BMI doesn't distinguish muscle from fat, so very muscular people can score ‘overweight’ while being lean. Pair BMI with body-fat % and waist measurements for athletes.

What is a healthy BMI range?

A BMI of 18.5–24.9 is classified as healthy weight. Below 18.5 is underweight, 25–29.9 is overweight, and 30 or above is obese.

Does BMI differ for men and women?

The BMI formula and adult categories are the same for both sexes. However, women naturally carry more body fat at the same BMI, so context matters when interpreting it.

What BMI is considered obese?

A BMI of 30 or higher is classified as obese: class I is 30–34.9, class II 35–39.9, and class III (severe) is 40 or above.

⚠️ Common Mistakes & Pro Tips

🔁 Handy Converters

Quick unit conversions related to this calculator:

🔁 kg → lb🔁 lb → kg🔁 cm → in🔁 ft → mAll converters →

? Frequently Asked Questions

Is BMI accurate for everyone? +
No, BMI has limitations. It may overestimate body fat in athletes and muscular people, and underestimate it in older adults who have lost muscle mass. It also doesn't account for differences in body composition, fat distribution, age, or ethnicity. For a complete assessment, consider combining BMI with other measurements like waist circumference and body fat percentage.
What's the ideal BMI for my age? +
While standard BMI categories apply to all adults, some research suggests slightly higher BMIs may be acceptable for older adults. For those over 65, a BMI of 23-30 may be optimal. For children and teens, BMI is calculated differently and compared to age and sex-specific percentiles.
Can I have a normal BMI but still be unhealthy? +
Yes! This is sometimes called "skinny fat" or metabolically obese normal weight (MONW). You can have a normal BMI but high body fat percentage, especially around the abdomen. This can still increase risk for heart disease and diabetes. Regular exercise and healthy eating are important regardless of BMI.
How often should I check my BMI? +
If you're actively trying to change your weight, checking monthly can help track progress. Otherwise, checking every few months to once a year is sufficient. Remember that daily weight fluctuates due to water retention, so focus on long-term trends rather than daily changes.
Is BMI different for men and women? +
The BMI formula and categories are the same for both sexes. However, women naturally carry more body fat than men at the same BMI. On average, a woman with a BMI of 25 has about 5% more body fat than a man with the same BMI. This is why some experts suggest considering sex-specific body fat percentage measurements.

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⚖️ Related Comparisons

Trying to decide between options? Read our side-by-side guides:

BMI vs Body Fat % Which metric is more accurate for tracking your health? Cardio vs Strength Training Which workout burns more calories long-term?

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