Ideal Weight Calculator

Calculate your ideal body weight using multiple scientific formulas

Calculate Your Ideal Body Weight

Personal Information

Age helps determine healthy weight ranges

Height (US Units)

Height (Metric)

Your Ideal Weight Based on Popular Formulas:

Formula Ideal Weight
Robinson (1983) -
Miller (1983) -
Devine (1974) -
Hamwi (1964) -
Healthy BMI Range -

About Ideal Weight Calculator

The Ideal Weight Calculator computes ideal body weight (IBW) ranges based on height and gender using multiple scientific formulas. While no single formula can definitively state the perfect weight for everyone, these calculations provide helpful reference points for healthy weight ranges.

What is Ideal Body Weight (IBW)?

Ideal Body Weight is an estimated weight range considered healthy for a person based on their height and gender. Originally developed to calculate medication dosages, IBW formulas are now widely used in healthcare, fitness, and sports for various applications including:

  • Determining appropriate medication and anesthesia dosages
  • Setting weight goals for athletes and bodybuilders
  • Classifying individuals for sports weight categories
  • Assessing overall health and fitness levels
  • Providing general weight management guidance

Ideal Weight Formulas

Our calculator uses four popular scientific formulas, each developed by medical researchers:

1. G.J. Hamwi Formula (1964)

Male: 48.0 kg + 2.7 kg per inch over 5 feet
Female: 45.5 kg + 2.2 kg per inch over 5 feet
Developed for medicinal dosage purposes. Tends to give higher weight estimates.

2. B.J. Devine Formula (1974)

Male: 50.0 kg + 2.3 kg per inch over 5 feet
Female: 45.5 kg + 2.3 kg per inch over 5 feet
Most widely used formula. Originally for medication dosing, became universal IBW determinant.

3. J.D. Robinson Formula (1983)

Male: 52 kg + 1.9 kg per inch over 5 feet
Female: 49 kg + 1.7 kg per inch over 5 feet
Modification of the Devine Formula with adjusted increments.

4. D.R. Miller Formula (1983)

Male: 56.2 kg + 1.41 kg per inch over 5 feet
Female: 53.1 kg + 1.36 kg per inch over 5 feet
Another Devine modification with different base weights and increments.

5. Healthy BMI Range

WHO Recommendation: BMI 18.5 - 25 for both genders
Based on Body Mass Index, provides weight range for any given height.

How Much Should I Weigh?

There's no single "perfect" weight for everyone. IBW formulas provide reference points, but your ideal weight depends on many individual factors:

Factors Affecting Ideal Weight:

  • Age: Muscle mass decreases with age; elderly may have different optimal weights
  • Gender: Men typically weigh more due to higher muscle mass and bone density
  • Height: Taller individuals naturally weigh more
  • Body Frame Size: Large-boned individuals weigh more than small-boned at same height
  • Muscle Mass: Athletes with high muscle mass may exceed IBW while being healthy
  • Body Composition: Fat vs. muscle ratio matters more than weight alone
  • Ethnicity: Different populations have varying body composition patterns
  • Health Conditions: Medical conditions can affect optimal weight

Body Frame Size

Body frame size significantly impacts ideal weight. Measure your wrist circumference to determine your frame size:

For Women:

Height Small Frame Medium Frame Large Frame
Under 5'2" < 5.5" 5.5" - 5.75" > 5.75"
5'2" - 5'5" < 6" 6" - 6.25" > 6.25"
Over 5'5" < 6.25" 6.25" - 6.5" > 6.5"

For Men (over 5'5"):

Frame Size Wrist Circumference
Small 5.5" - 6.5"
Medium 6.5" - 7.5"
Large > 7.5"

Large-framed individuals naturally weigh more than small-framed people at the same height, which is completely normal and healthy.

Limitations of IBW Formulas

It's crucial to understand that IBW formulas have significant limitations:

Limited Factors: Formulas only consider height and gender, ignoring body composition, muscle mass, bone density, fat distribution, and activity level.
Not for Athletes: Highly fit athletes with significant muscle mass may be classified as "overweight" by IBW despite being perfectly healthy.
Population Averages: Formulas are designed for broad applicability, so they can't be highly accurate for every individual.
No Physical Handicaps Consideration: Formulas don't account for amputations or physical disabilities that affect weight.
Extreme Heights: Less accurate for very tall or very short individuals who fall outside typical ranges.

IBW vs. BMI

Both IBW and BMI are weight assessment tools, but they work differently:

Ideal Body Weight (IBW):

  • Provides specific weight target based on height and gender
  • Uses formulas derived from population studies
  • Originally developed for medical dosing calculations
  • Gives single value or narrow range
  • Different formulas yield slightly different results

Body Mass Index (BMI):

  • Calculates weight-to-height ratio
  • Provides weight range (18.5-25 BMI = healthy)
  • Used for population health screening
  • Single standardized calculation
  • More widely used in clinical settings

Key Difference: BMI provides a range (e.g., 128-174 lbs for your height), while IBW formulas provide specific targets (e.g., 156 lbs). Neither is perfect for everyone.

When IBW Matters Most

IBW calculations are particularly important in these contexts:

Medical Applications:

  • Medication Dosing: Many drugs are dosed based on IBW, especially in obese patients
  • Anesthesia: Calculating appropriate anesthetic doses
  • Nutritional Support: Determining caloric needs for tube feeding or IV nutrition
  • Dialysis: Calculating treatment parameters

Sports and Fitness:

  • Weight Classes: Boxing, wrestling, MMA fighters need to make weight
  • Performance Optimization: Some sports benefit from specific weight ranges
  • Body Composition Goals: Setting realistic targets for physique athletes

Understanding the Results

When you receive your IBW results:

Multiple Values are Normal: Different formulas yield different results (often 5-15 lbs variation). This is expected and shows the inherent uncertainty in ideal weight determination.
Use as Reference, Not Gospel: IBW is a guideline, not a requirement. Being slightly above or below doesn't mean you're unhealthy.
Consider the Range: The BMI-based range (18.5-25) gives you flexibility. You might feel and perform best at the lower, middle, or higher end of this range.
Focus on Health, Not Numbers: Good health markers (blood pressure, cholesterol, blood sugar, fitness level) matter more than matching a specific number.

What Matters More Than Weight

Instead of obsessing over reaching an "ideal" weight, focus on these health indicators:

Health Markers:

  • Blood pressure in healthy range (< 120/80 mmHg)
  • Cholesterol levels within normal limits
  • Fasting blood sugar under 100 mg/dL
  • Resting heart rate 60-100 bpm
  • Good sleep quality (7-9 hours)

Fitness Indicators:

  • Ability to perform daily activities without excessive fatigue
  • Cardiovascular endurance
  • Muscle strength and flexibility
  • Good balance and coordination
  • Energy levels throughout the day

Body Composition:

  • Body fat percentage in healthy range
  • Adequate muscle mass
  • Waist circumference (< 40" men, < 35" women)
  • Waist-to-hip ratio

Lifestyle Factors:

  • Eating a balanced, nutritious diet
  • Regular physical activity (150+ min/week)
  • Managing stress effectively
  • Maintaining social connections
  • Positive mental health

How to Reach Your Ideal Weight

If your current weight differs significantly from IBW estimates and you want to make changes:

For Weight Loss:

  • Create modest calorie deficit (300-500 calories daily)
  • Focus on whole, unprocessed foods
  • Increase protein intake to preserve muscle
  • Incorporate strength training 2-3x weekly
  • Add cardio 3-5x weekly
  • Aim for 0.5-2 lbs loss per week
  • Be patient - sustainable loss takes time

For Weight Gain:

  • Increase calorie intake by 300-500 daily
  • Eat nutrient-dense, calorie-rich foods
  • Focus on protein (0.8-1g per lb body weight)
  • Strength train consistently to build muscle
  • Eat 5-6 smaller meals throughout day
  • Track progress weekly
  • Ensure gains are muscle, not just fat

Special Considerations

For Children and Teens:

IBW formulas are designed for adults age 18+. For children and adolescents, use BMI-for-age percentiles from the CDC. Growth patterns are more important than specific weight targets during development.

For Older Adults:

After age 40, people naturally lose muscle mass and bone density. Some research suggests slightly higher weights (BMI 25-27) may be healthier for seniors. Focus on maintaining muscle through resistance training and adequate protein intake.

For Pregnant Women:

Pre-pregnancy IBW can help determine appropriate pregnancy weight gain targets. Recommended gain varies based on starting BMI: 25-35 lbs for normal weight, 15-25 lbs for overweight, 11-20 lbs for obese women.

For Athletes:

Athletes with significant muscle mass often exceed IBW estimates while maintaining excellent health. Body composition measurements (body fat percentage, lean mass) are more relevant than weight for athletes.

Example Calculations

Example 1 - Male, 5'10" (70 inches):
Robinson: 52 + 1.9(10) = 71 kg (156.5 lbs)
Miller: 56.2 + 1.41(10) = 70.3 kg (155 lbs)
Devine: 50 + 2.3(10) = 73 kg (160.9 lbs)
Hamwi: 48 + 2.7(10) = 75 kg (165.3 lbs)
BMI Range: 128.9 - 174.2 lbs
Example 2 - Female, 5'5" (65 inches):
Robinson: 49 + 1.7(5) = 57.5 kg (126.8 lbs)
Miller: 53.1 + 1.36(5) = 59.9 kg (132 lbs)
Devine: 45.5 + 2.3(5) = 57 kg (125.7 lbs)
Hamwi: 45.5 + 2.2(5) = 56.5 kg (124.6 lbs)
BMI Range: 111.2 - 150.2 lbs

Common Myths About Ideal Weight

Myth: Everyone at my height should weigh the same
Reality: Body frame, muscle mass, bone density, and genetics create healthy variation. Two people of identical height can have 20+ pound difference in healthy weight.
Myth: I need to match my IBW exactly to be healthy
Reality: IBW is a reference point. Being 10-15 pounds above or below while maintaining good health markers is perfectly fine.
Myth: Lower weight is always better
Reality: Being underweight carries health risks including weakened immunity, bone loss, and fertility issues. There's an optimal range, not "the lower the better."
Myth: Ideal weight remains constant throughout life
Reality: Healthy weight ranges can shift with age, especially after 40. Some weight gain with aging is normal and may even be protective for older adults.

Frequently Asked Questions

Why do the different formulas give different results?

Each formula was developed by different researchers using different population studies and methodologies. Variations of 5-15 pounds between formulas are normal. No single formula is definitively "correct" - they all provide reasonable estimates within a range.

Which formula should I use?

The Devine formula is most widely used clinically. However, considering all formulas and the BMI-based range gives you a better overall picture. If all formulas cluster around a similar weight, that's a strong indicator of your IBW range.

I'm very muscular - will these formulas be accurate for me?

No, IBW formulas don't account for muscle mass. Athletes and bodybuilders often exceed IBW while having low body fat and excellent health. Body composition analysis (body fat percentage, lean mass) is more relevant than IBW for athletic individuals.

Should I lose/gain weight to reach my IBW?

Not necessarily. IBW is a reference point, not a requirement. If you're currently healthy with good blood markers, fitness level, and body composition, your current weight may be ideal for YOU even if it differs from calculated IBW. Consult healthcare providers before major weight changes.

Why is there such a wide BMI-based range?

The BMI range (18.5-25) accommodates different body types, frames, and compositions. Some people feel and perform best at BMI 19, others at 24. Both can be equally healthy. The range provides flexibility for individual variation.

How accurate are these calculations?

IBW formulas provide reasonable estimates for average populations but can vary significantly for individuals. They're most accurate for people of average height and build. Consider them general guidelines rather than precise targets.

When to Consult Healthcare Professionals

Seek professional guidance if:

  • Your current weight differs by more than 25% from IBW estimates
  • You have rapid, unexplained weight changes
  • You're experiencing weight-related health issues
  • You have a history of eating disorders
  • You're pregnant or planning pregnancy
  • You have medical conditions affecting weight (thyroid, diabetes, etc.)
  • You're planning significant weight loss (> 50 lbs)
  • You need help developing a safe weight management plan

Important Disclaimer

This ideal weight calculator provides estimates based on established scientific formulas. These results are reference points only and should not be interpreted as strict targets you must achieve. Individual ideal weights vary significantly based on body composition, frame size, muscle mass, genetics, and overall health. Being above or below calculated IBW does not necessarily indicate poor health. These calculations are not suitable for children under 18, pregnant women, or individuals with certain medical conditions. Always consult qualified healthcare professionals before making significant changes to your weight, diet, or exercise routine. The calculator is meant as a general educational tool and does not replace professional medical advice, diagnosis, or treatment.

Privacy and Security

All ideal weight calculations are performed directly in your browser using JavaScript. We do not store, collect, or transmit any of your personal information. Your height, age, gender, and other data remain completely private on your device.

Mobile Friendly

Our ideal weight calculator is fully responsive and works perfectly on all devices including smartphones, tablets, and desktop computers. Calculate your ideal body weight on the go, anytime, anywhere!