What BMI is considered overweight?

According to the WHO and CDC, a BMI of 25.0 to 29.9 is classified as overweight. A BMI of 30.0 or above is obese. The normal/healthy range is 18.5 to 24.9. These thresholds apply to adults 18 and over.

Is BMI an accurate measure of health?

BMI is a useful but imperfect screening tool. It correlates well with health risks at a population level but doesn't distinguish between muscle and fat, doesn't account for fat distribution, and may be less accurate for certain ethnic groups. It's best used alongside body fat percentage, waist circumference, and metabolic markers.

How much weight do I need to lose to reach a healthy BMI?

Target weight = 24.9 × height² (m²). For example, at 5'9" (1.753m), maximum healthy weight is 24.9 × 1.753² = 76.5 kg. However, any weight reduction within the overweight range brings meaningful health benefits.

What is the healthiest BMI?

Research suggests the lowest all-cause mortality risk is associated with a BMI of 20-25, with the single lowest risk point around 22-23. The WHO normal range of 18.5-24.9 reflects this. A BMI slightly under 18.5 also carries health risks.

What is the difference between overweight and obese?

Overweight (BMI 25-29.9) carries increased risk but is moderate. Obesity (BMI 30+) is associated with substantially higher risk of diabetes, cardiovascular disease, and other conditions. Obesity is divided into Class I (30-34.9), Class II (35-39.9), and Class III (40+).

Can I be overweight but still healthy?

Yes. Cardiorespiratory fitness is a stronger predictor of longevity than BMI alone. Someone with a BMI of 27 who exercises regularly with normal blood markers is at lower risk than a sedentary person with BMI 22. However, most studies show excess weight increases risk at a population level over time.

⚕ BMI · WHO Standards · US & Metric · Healthy Weight Range

Overweight Calculator

Check your BMI and weight status using WHO and CDC standards. See your healthy weight range, how far you are from it, and personalized health context.

ℹ️ This tool is for informational purposes only. Always consult a healthcare provider for medical advice.

⚕

Your Information

Age

yrs

Biological Sex

Height

Weight

lbs

⚕️

Enter your details above

Your BMI and weight status will appear here

—

BMI (kg/m²)

—

1518.525303540+

Your BMI

—

Weight Diff

—

to normal

Prime BMI

22.5

Midpoint optimal

Height

—

Healthy Weight Range for Your Height

—

BMI 18.5 – 24.9 (WHO Normal range)

— —

BMI Classification (WHO)

Next step: Know your BMI — now find your daily calorie needs with our BMR Calculator and Calorie Calculator to create a realistic, sustainable plan.

Understanding Your Weight Status — BMI Explained

BMI (Body Mass Index) is the most widely used screening tool for assessing whether a person's weight is in a healthy range relative to their height. It is used by doctors, public health organisations (WHO, CDC, NHS), and researchers worldwide as a simple, standardised population-level metric. This calculator uses the standard adult BMI classification and shows your result in the context of all weight categories — from underweight to Class III obesity. For a more complete picture, combine this with our Body Fat Calculator and Ideal Weight Calculator.

The BMI Formula

BMI Formula

BMI (metric) = weight (kg) / height² (m²) BMI (US/imperial) = 703 × weight (lbs) / height² (inches²)

Example: 5'9" (175.3 cm), 180 lbs (81.6 kg) → BMI = 703 × 180 / (69²) = 26.6 → Overweight

WHO BMI Classification for Adults

Category	BMI Range	Health Risk
Underweight (Severe)	Below 16.0	Very High
Underweight (Moderate)	16.0 – 16.9	High
Underweight (Mild)	17.0 – 18.4	Moderate
Normal Weight	18.5 – 24.9	Lowest risk
Overweight (Pre-obese)	25.0 – 29.9	Increased
Obese Class I	30.0 – 34.9	High
Obese Class II	35.0 – 39.9	Very High
Obese Class III (Morbid)	40.0 and above	Extremely High

Limitations of BMI — What It Doesn't Tell You

💪

Muscle vs Fat

BMI doesn't distinguish between muscle and fat. Athletes may have a high BMI but low body fat. Use our Body Fat Calculator for a more accurate picture.

👴

Age & Bone Density

Older adults tend to have more body fat at the same BMI. BMI thresholds for children and teens differ significantly from adults — always use age-specific charts for under-18s.

🌍

Ethnic Variation

Some Asian populations face health risks at lower BMI thresholds (≥23 overweight, ≥27.5 obese). The WHO has established these alternate cut-points for Asian populations.

📍

Fat Distribution

Where you carry weight matters as much as how much. Waist circumference is a better predictor of cardiovascular risk than BMI alone. Men >40in / Women >35in is high risk.

Health Risks of Being Overweight

According to the WHO and CDC, carrying excess weight (BMI 25+) is associated with increased risk of type 2 diabetes, heart disease, hypertension, sleep apnoea, certain cancers, joint problems, and reduced mobility. However, the degree of excess weight matters — someone with a BMI of 26 faces far less risk than someone with BMI 38. Small, sustainable changes in weight can significantly reduce health risks. Use our Calorie Calculator to find your daily energy needs and our BMR Calculator for your basal metabolic rate — both essential starting points for any weight management plan.

Frequently Asked Questions

Common questions about BMI, overweight status, and healthy weight

According to the WHO and CDC, a BMI of 25.0 to 29.9 is classified as overweight (also called "pre-obese"). A BMI of 30.0 or above is classified as obese (with three severity classes: Class I 30–34.9, Class II 35–39.9, Class III 40+). A BMI between 18.5 and 24.9 is the normal/healthy range, and below 18.5 is underweight. These thresholds apply to adults aged 18 and over. For children and teens (2–19 years), weight status is determined by BMI-for-age percentile charts, not fixed thresholds. Use our BMI Calculator for a detailed breakdown including your percentile if applicable.

BMI is a useful but imperfect screening tool. It correlates well with health risks at a population level, which is why it's widely used in public health. However, it has important limitations at the individual level: it doesn't distinguish between muscle and fat (a muscular athlete may have a high BMI but excellent health); it doesn't account for fat distribution (visceral fat around the waist is more dangerous than subcutaneous fat); and it may be less accurate for certain ethnic groups. For individuals, BMI is best used alongside other measures: body fat percentage, waist circumference, blood pressure, cholesterol, and blood glucose. Always consult a healthcare professional for a complete health assessment.

This calculator shows exactly how much weight you'd need to lose (or gain) to reach the top of the normal BMI range (BMI 24.9). The formula is: Target weight = 24.9 × height² (m²). For example, someone 5'9" (1.753m) has a target max weight of 24.9 × 1.753² = 76.5 kg (168.6 lbs). If they weigh 90 kg, they'd need to lose 13.5 kg to enter the normal range. However, any weight reduction within the overweight or obese range brings meaningful health benefits — you don't need to reach the "ideal" BMI to reduce risk. Use our Calorie Calculator and BMR Calculator to plan a realistic deficit.

For adults (18+), the same BMI thresholds apply regardless of age (18.5–24.9 normal, 25–29.9 overweight, etc.). However, older adults (65+) may be at increased risk at lower BMIs due to loss of muscle mass and bone density — some research suggests a slightly higher "healthy" BMI (around 23–27) for seniors. For children and teens (2–17 years), BMI is calculated the same way but interpreted using age-and-sex-specific growth charts — the same number means very different things at age 8 vs age 16. This calculator applies adult WHO classifications. Always use pediatric tools for children. Our Ideal Weight Calculator provides age-adjusted context.

Research suggests the lowest all-cause mortality risk is associated with a BMI in the range of 20–25, with the single lowest risk point around 22–23 for most adults. The WHO "normal" range of 18.5–24.9 reflects this. Having a BMI just under 18.5 (mild underweight) carries its own health risks including nutrient deficiencies, bone density loss, and immune compromise. The "prime BMI" of 22.5 shown in this calculator represents the midpoint of the safest range. Note that a BMI slightly in the overweight range (25–27) may carry minimal additional risk for people who are physically active with good metabolic health. Use our Body Fat Calculator alongside BMI for a fuller picture.

Both terms describe excess body weight relative to height, but differ in severity and health risk. Overweight (BMI 25–29.9) carries increased risk of certain conditions but is generally a moderate risk category — many overweight individuals have no serious health complications. Obesity (BMI 30+) is associated with substantially higher risk of type 2 diabetes, cardiovascular disease, hypertension, sleep apnoea, joint disease, and certain cancers. Obesity is further divided: Class I (30–34.9, high risk), Class II (35–39.9, very high risk), and Class III (40+, extremely high risk, sometimes called morbid obesity). The distinction matters for treatment: overweight is often addressed with lifestyle changes, while severe obesity may benefit from medical or surgical intervention. Consult a healthcare provider for personalised guidance. Track your calorie intake with our Calorie Calculator.

Yes — this is sometimes called "metabolically healthy obesity" or simply being fit but overweight. Research shows that cardiorespiratory fitness is a stronger predictor of longevity than BMI alone. Someone with a BMI of 27 who exercises regularly, has normal blood pressure, cholesterol, and blood sugar is at far lower health risk than a sedentary person with a BMI of 22. However, most large-scale studies still show that excess weight increases risk at a population level — the "healthy overweight" phenomenon tends to be temporary, with metabolic complications developing over time. The most robust health profile combines a healthy BMI with physical fitness, good nutrition, and normal metabolic markers. Use our Pace Calculator to support your fitness routine.