Ideal Weight Calculator
Calculate your Ideal Body Weight (IBW) to help you understand your weight status relative to clinical benchmarks for long-term health.
How It Works
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Why Use It
Multiple Formula Analysis - Compares the Hamwi, Devine, Robinson, and Miller formulas to provide a well-rounded average estimate.
WHO Standard Alignment - Includes a healthy weight range based on World Health Organization BMI guidelines (18.5–25).
Fast, Evidence-Based Results - Get an immediate screening of your weight status without the need for complex medical equipment.
Built by Everlab's Medical Team - Developed by Everlab’s medical experts to provide evidence-informed guidance for your preventative health journey.
Disclaimer
These results are general estimates only and are not a substitute for professional medical advice. Your individual ideal weight may differ based on factors such as muscle mass, bone density, physical activity levels, and medical history. These figures should not be interpreted as definitive health targets or goals. Always consult with a healthcare professional before making significant changes to your weight management plan.
Everlab’s Ideal Weight Calculator
Most people view weight as a single, static number, but "ideal weight" is a spectrum influenced by your unique biology and health goals. Understanding where you sit relative to clinical benchmarks is an essential starting point for any preventative health strategy.
That is why we created the Everlab Ideal Weight Calculator: to provide a nuanced, data-driven perspective that moves beyond a single formula.
By averaging the most respected clinical equations - Hamwi, Devine, Robinson, and Miller - we offer a more reliable estimate of your body’s baseline.
The more accurately you understand your weight in relation to your height and health, the more control you have over your longevity.
The best part? It takes less than a minute, uses simple metrics, and costs nothing.
Why Your Weight Baseline Matters
Weight is a key indicator of metabolic health, but the "ideal" number is about more than just aesthetics.
- Preventative Health: Maintaining a weight within the healthy BMI range reduces the long-term risk of cardiovascular disease, type 2 diabetes, and joint issues.
- Metabolic Vitality: A stable, healthy weight supports efficient hormone production and blood sugar regulation.
- Functional Longevity: Understanding your healthy range helps you focus on maintaining the right balance of lean mass as you age.
- Sustainable Goals: Having an evidence-based "landing zone" prevents the pursuit of unrealistic or unhealthy weight targets.
What is an Ideal Weight Calculator?
An ideal weight calculator is a screening tool that uses height and gender to estimate a weight range associated with the lowest statistical risk of chronic disease.
Our calculator provides results across several clinical standards:
- Clinical Formulas (Hamwi, Devine, Robinson, Miller): These use different mathematical models to calculate a specific "ideal" number based on height.
- Average Estimate: A composite average of all four formulas to provide a more balanced target.
- Healthy BMI Range: The weight range where your Body Mass Index falls between 18.5 and 25, according to WHO guidelines.
Who Should Use This Calculator?
Everlab’s ideal weight calculator is designed for individuals who want an evidence-based starting point for their body composition journey.
You should use this calculator if you are:
- An adult looking to understand your weight status relative to clinical benchmarks.
- Someone setting long-term health goals who needs a science-backed "healthy range" to aim for.
- Proactively monitoring your health as part of a preventative wellness plan.
Do NOT use this calculator if you are:
- An Elite Athlete or Bodybuilder: High muscle mass can lead to a "High BMI" or "Overweight" classification that does not reflect actual health or body fat levels.
- Pregnant or Breastfeeding: Your body’s weight requirements are significantly altered during these periods.
- Under 18 Years Old: Children and adolescents require specialised growth charts and paediatric assessment.
- Living with an Eating Disorder: If you have a history of disordered eating, tracking weight targets may not be the appropriate path for your journey.
Ideal Weight Calculator Formulas
The following formulas were originally developed in medical contexts, primarily for calculating medication dosages rather than defining health goals. They provide general estimates based on height and gender.
Hamwi Formula - 1964
Originally developed for medication dosing purposes. Uses 48 kg for men and 45.5 kg for women at 152 cm (5 feet), adding weight per 2.54 cm (1 inch) over this baseline.
Men: Men: 48 kg + 2.7 kg per 2.54 cm over 152 cm
Women: Women: 45.5 kg + 2.2 kg per 2.54 cm over 152 cm
Devine Formula - 1974
Commonly referenced in clinical settings, particularly for determining drug dosages. Became one of the most frequently cited formulas for IBW estimation.
Men: Men: 50 kg + 2.3 kg per 2.54 cm over 152 cm
Women: Women: 45.5 kg + 2.3 kg per 2.54 cm over 152 cm
Robinson Formula - 1983
A modification of the Devine formula based on updated population data. Generally produces slightly lower estimates than other formulas.
Men: Men: 52 kg + 1.9 kg per 2.54 cm over 152 cm
Women: Women: 49 kg + 1.7 kg per 2.54 cm over 152 cm
Miller Formula - 1983
Another modification intended to be more representative of a broader population. Generally produces slightly higher estimates.
Men: Men: 56.2 kg + 1.41 kg per 2.54 cm over 152 cm
Women: Women: 53.1 kg + 1.36 kg per 2.54 cm over 152 cm
Understanding Your Results
After you complete the calculation, you will see your results broken down by formula:
- The Averages: These give you a specific "point" to consider.
- The Range: This provides the "Healthy BMI" window, which is often a more practical guide for long-term maintenance.
Factors That May Influence Ideal Weight
The following factors can influence what constitutes a healthy weight for an individual. A registered health practitioner can help assess these factors in relation to your personal circumstances.
Age
Body composition naturally changes with age. Muscle mass tends to decrease while fat mass may increase. Older adults may have different healthy weight considerations than younger adults of the same height. The formulas used here were primarily developed for adult populations.
Gender
Men and women typically have different body compositions due to hormonal differences. Men generally have higher muscle mass, while women have essential fat stores related to reproductive functions. This is why all IBW formulas use different calculations for men and women.
Body Frame Size
Bone structure varies between individuals. Someone with a larger frame (broader shoulders, larger wrists and elbows) will naturally weigh more than someone with a smaller frame at the same height. The frame size adjustment in this calculator applies a 10% increase or decrease to estimates.
One method to estimate frame size:
- Wrap your thumb and middle finger around your wrist
- If they overlap: May indicate a smaller frame
- If they just touch: May indicate a medium frame
- If they don't touch: May indicate a larger frame
This is a rough guide only and should not be considered a clinical assessment.
Ethnicity and Ancestry
These formulas were developed primarily using data from Caucasian populations and may not be equally applicable to all ethnic groups. Body composition and fat distribution patterns can vary significantly between different populations. Australian health guidelines recognise these variations, particularly for Aboriginal and Torres Strait Islander peoples and those of Asian, South Asian, and Pacific Islander backgrounds.
Physical Activity and Muscle Mass
Individuals who are physically active or have higher muscle mass may have higher body weights while still being healthy. These formulas do not account for body composition differences between active and sedentary individuals.
What the Calculator Cannot Tell You
This calculator is for general educational and informational purposes only. It does not constitute medical advice, is not intended to diagnose or treat any health condition, and should not replace consultation with qualified registered health practitioners. Always seek the advice of your GP, Accredited Practising Dietitian (APD), or other qualified health professional with any questions you may have regarding your health or weight management.
Most of these formulas were originally developed to calculate medication dosages in clinical settings, not to define health goals. They were designed for quick estimates and have limitations when used as health targets.
It does not cover:
- Body Composition: It cannot distinguish between muscle, bone density, and body fat.
- Fat Distribution: It does not account for where fat is stored (e.g., visceral fat around organs), which is a key marker of metabolic risk.
- Nutritional Status: A "healthy weight" does not automatically mean a person is meeting their micronutrient or protein requirements.
- Height Limitations: These formulas are based on a 152 cm (5 foot) baseline and add weight per centimetre above that height. They may be less accurate for individuals significantly shorter than 152 cm or exceptionally tall.
For a comprehensive understanding of your health, consider discussing the following with a registered health practitioner:
- Body composition assessment (available through some allied health professionals)
- Waist circumference and waist-to-hip ratio
- Blood pressure and cholesterol levels
- Physical fitness and functional capacity
- Overall lifestyle, nutrition, and wellbeing
- Family history and individual risk factors
Why is Comprehensive Testing Important?
Weight is only one chapter of your health story. At Everlab, we believe true preventative health requires looking "under the hood" to see what that weight actually consists of.
A comprehensive Everlab assessment goes beyond weight to include:
- DEXA Scanning: The gold standard for measuring your exact muscle-to-fat ratio and bone mineral density.
- Visceral Fat Analysis: Measuring the dangerous fat around your organs that weight alone can't detect.
- Metabolic Blood Markers: Checking markers like ApoB, HbA1c, and insulin to see how your weight is impacting your internal health.
Frequently Asked Questions
1. Why are there four different formulas?
Different formulas were developed over time for different clinical purposes (like calculating medication dosages). We provide an average to give you the most consistent "middle ground" estimate.
2. Can I be "overweight" on the calculator but still healthy?
Yes. If you have significant muscle mass, your weight may be higher than these formulas suggest, while your metabolic health remains excellent. This is why we recommend comprehensive testing.
3. How often should I check my ideal weight?
Your ideal weight doesn't change much as an adult unless you have a major shift in goals (like significant muscle building), but you should track your actual weight regularly as a preventative health metric.