Ideal Weight Calculator
Calculate your ideal weight range using four established formulas. ASEAN-adjusted.
Ideal Weight Calculator Tool
Disclaimer: Results are reference ranges only and are not a substitute for professional medical advice. "Ideal weight" varies with body composition, muscle mass, age, and health status — consult a healthcare provider for personalised guidance.
How to Use the Ideal Weight Calculator
Select your unit system and enter your height
Choose Metric (cm/kg) or Imperial (ft·in/lbs) using the toggle at the top. Enter your height — for imperial, use two separate fields for feet and inches. All formulas convert internally to inches for calculation.
Choose your biological sex
Select Male or Female — all five formulas produce significantly different results between the two. The Devine formula, for example, gives a 4.5 kg difference at 170 cm between male and female results.
Click Calculate to see all five formulas
Results appear instantly — a consensus ideal weight range (average of 4 clinical formulas ± 5%), a full formula breakdown table, and the ASEAN BMI range based on HPB Singapore guidelines (18.5–22.9).
Use the ASEAN BMI range as your primary target
If you live in Singapore, Malaysia, or Indonesia, the BMI 18.5–22.9 row is your most clinically relevant benchmark. All four classic formulas were developed on Western populations and tend to overestimate ideal weight for Asian adults.
Ideal Weight — Why One Number Can't Tell the Whole Story
Why There Is No Single "Ideal Weight" — and What That Means for ASEAN Bodies
The concept of an "ideal body weight" has a surprisingly bureaucratic origin. In the early 20th century, life insurance companies in the United States began collecting height and weight data from policyholders to predict mortality risk. The Metropolitan Life Insurance Company published widely-cited "desirable weight" tables in 1943 and again in 1959 and 1983, establishing weight ranges linked to the lowest mortality rates in their policyholder cohorts — almost exclusively white Americans with above-average socioeconomic status.
The four clinical formulas that followed — Hamwi (1964), Devine (1974), Robinson (1983), and Miller (1983) — were all derived, directly or indirectly, from this actuarial foundation. None of them used data from Asian, African, or Latin American populations. Their accuracy for ASEAN bodies has been questioned in peer-reviewed literature for decades. When applied to Singaporeans, Malaysians, or Indonesians, these formulas often yield results 5–10% higher than what the HPB Singapore and WHO WPRO consider the ideal range — a clinically meaningful discrepancy.
Two further limitations apply regardless of population. First, all these formulas treat weight as a function of height alone — they completely ignore body composition, bone density, age, and fitness level. Muscle tissue is approximately 18% denser than fat; a well-trained person at the same height may legitimately weigh well above the formula result while having far better health markers. Second, the concept of a single-point "ideal weight" has been gradually replaced in clinical medicine by a preference for weight ranges and metabolic markers rather than a specific number on a scale. That is why this calculator presents a range, not a single target.
"The Devine formula was developed for pharmacologists to calculate drug dosing in 1974 — yet it became the most widely used 'ideal body weight' formula in clinical settings worldwide."
The Five Formulas Explained: Which One Should You Trust?
Robinson (1983) is the most widely cited formula in clinical and research literature. It was derived from the 1983 Metropolitan Life Insurance tables and is used in US military screening protocols. For a 170 cm male it gives 66.5 kg; for a female 62.3 kg.
Miller (1983) was also developed from Metropolitan Life data, using a slightly different regression approach that produces lower estimates than Robinson at taller heights. It was intended as a refinement of the earlier Devine formula for hospital settings.
Devine (1974) is the formula most embedded in clinical practice globally — primarily because it was published in a pharmacology reference (Devine, B.J., Drug Intelligence and Clinical Pharmacy, 1974) and adopted by hospital pharmacy systems for drug dosing calculations. Despite being designed for pharmacologists — not dietitians or fitness professionals — it became a de facto clinical standard. Its male formula (50 + 2.3 per inch above 5 ft) produces the highest estimates at tall heights among the four.
Hamwi (1964) is the simplest and oldest formula, designed as a rule of thumb for dietitians: 48 kg (male) or 45.4 kg (female) for 5 feet, plus 2.7 kg (male) or 2.3 kg (female) per inch above 5 feet. It predates all the others and is less frequently cited in modern clinical literature, but remains in use in dietitian training.
BMI 18.5–22.9 (HPB Singapore) takes a fundamentally different approach — it is a population-level statistical range rather than a height-based regression. For Asian adults in Singapore, Malaysia, and Indonesia, this is the most clinically supported benchmark. The WHO WPRO issued Asia-Pacific-specific BMI thresholds in 2000 after research showed that Asian populations develop type 2 diabetes and cardiovascular disease at BMI values well below Western cutoffs. The result: a BMI of 22.9 — not 24.9 — marks the upper end of the normal healthy range for Asian adults.
For the consensus range, this calculator uses the mean of Robinson, Miller, Devine, and Hamwi — the four formula-based approaches — and applies a ± 5% margin to acknowledge the inherent uncertainty in any single formula estimate. Use the ASEAN BMI row as your primary reference if you are of Asian descent.
Ideal Weight vs Healthy Weight: The Important Difference for Singaporeans
There is a critical distinction that gets lost in popular discussions of ideal weight: statistical ideal weight versus individual healthy weight. The formulas on this page give you the statistical average — the weight at which a person of your height, as represented in the original study population, had the best actuarial outcomes. This is not the same as the weight at which YOUR metabolic markers are optimal.
Singapore's Population Health Survey found that 40% of adults within the "healthy" BMI range of 18.5–22.9 still had at least one cardiometabolic risk factor — elevated blood pressure, fasting glucose, or cholesterol. This is partly explained by the "skinny-fat" paradox particularly common in ASEAN populations: a person can be within the ideal weight range while carrying excess visceral fat (fat surrounding the internal organs), which drives metabolic disease independently of total body weight. For this reason, Singapore's HPB recommends measuring waist circumference alongside BMI: below 90 cm for men and 80 cm for women as the abdominal obesity cutoffs for Asian adults.
The practical takeaway for Singaporeans: use this calculator as a starting point, not an endpoint. If your weight is within the consensus range or the ASEAN BMI band, that is a positive signal — but the most important numbers to monitor are your blood pressure, HbA1c, fasting lipids, and waist circumference, obtainable through a routine health screening at any polyclinic or CHAS clinic.
10 Facts About Ideal Weight Formulas
The Robinson Formula (1983) is the most commonly cited in clinical literature — originally derived from actuarial data from the Metropolitan Life Insurance Company.
The Devine Formula (1974) was never intended as a health standard — it was developed for calculating drug dosage adjustments based on body weight in pharmacology.
All four ideal weight formulas were developed primarily using data from white males in the United States and Europe — their accuracy for Asian populations has been widely questioned.
Singapore's HPB recommends a BMI of 18.5–22.9 for Asian adults — significantly lower than the Western "healthy" BMI ceiling of 24.9.
The four main ideal weight formulas can give results that differ by up to 10% for the same individual — showing there is no single "correct" answer.
Muscle tissue is approximately 18% denser than fat — meaning two people at the same "ideal weight" can have dramatically different body compositions.
Bone density accounts for approximately 15% of body weight — meaning heavier bone structure legitimately places someone above standard ideal weight ranges.
Singapore's Population Health Survey found that 40% of adults within the "healthy" BMI range still had at least one cardiometabolic risk factor such as high blood pressure or cholesterol.
The WHO's Western BMI cutoff of 24.9 was established in 1997 — followed by WPRO Asia-Pacific guidelines in 2000 recommending 22.9 as the Asian normal limit.
The average Singaporean adult male is approximately 170 cm and 70 kg (BMI ~24.2) — technically within "acceptable" range but above the HPB-recommended ideal of 18.5–22.9.
Frequently Asked Questions
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No single formula is universally accurate — each was developed for a specific population and purpose. The Robinson (1983) formula is the most widely cited in clinical literature. For Asian adults in Singapore, Malaysia, and Indonesia, the BMI range of 18.5–22.9 recommended by HPB Singapore and WHO WPRO is the most clinically relevant benchmark, as all four single-point formulas were derived from predominantly Western populations.
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Each formula was developed independently using different datasets and assumptions. Robinson (1983) and Miller (1983) drew on actuarial data from Metropolitan Life Insurance. Devine (1974) was designed for pharmacological drug dosing. Hamwi (1964) used a simple rule-of-thumb approach for dietitians. Their differences reflect the varied datasets and eras in which they were created — which is why using a consensus range across all four gives a more reliable picture than relying on any single formula.
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Yes. All four classic formulas were developed using data from predominantly white males in the United States and Europe. For Asian adults including Singaporeans, Malaysians, and Indonesians, HPB Singapore and WHO WPRO recommend a BMI target of 18.5–22.9 rather than the Western 18.5–24.9. Asian populations tend to carry more visceral fat at the same BMI, increasing cardiometabolic risk at lower weights than Western populations.
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The Devine formula (1974) was originally developed by Dr B.J. Devine for pharmacologists to calculate drug dosage adjustments based on a patient's ideal body weight (IBW). It was never intended as a health or fitness standard. Despite this, it became the most widely used IBW formula in clinical and hospital settings worldwide — largely because it was the first formula published in a widely-read pharmacology reference and was subsequently adopted without validation for fitness purposes.
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Yes, significantly. Muscle tissue is approximately 18% denser than fat, so a muscular person may weigh considerably more than these formulas suggest while being in excellent health. All four classic formulas and the BMI approach are designed for the general population and do not distinguish between muscle and fat. Athletes and people who lift weights regularly should not rely on these formulas in isolation — a body composition analysis (DEXA or skinfold) is more informative.
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Ideal weight is a statistical estimate derived from population-level data — the weight at which an average person of a given height is expected to have the best health outcomes. Healthy weight is the weight at which YOUR individual health markers (blood pressure, fasting glucose, cholesterol, waist circumference) are within optimal ranges. Two people of identical height can have very different healthy weights depending on body composition, genetics, age, and medical history. Singapore's HPB recommends using waist circumference alongside BMI for a more complete picture.
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The Health Promotion Board (HPB) Singapore recommends a BMI of 18.5–22.9 for Asian adults as the normal healthy range, aligned with WHO WPRO Asia-Pacific guidelines published in 2000. This is lower than the Western healthy BMI range of 18.5–24.9 because research shows that Asian populations carry more visceral fat (fat around internal organs) at equivalent BMI values, increasing cardiometabolic risk at lower weights than Western populations.
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The classic formulas were developed primarily using data from adults aged 18–60. For older adults (60+), some research suggests that a slightly higher BMI (up to 27) may be associated with better outcomes due to muscle mass preservation. If you are over 60, consult a geriatrician or registered dietitian rather than relying solely on these population-level formulas.
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Not necessarily. The consensus range represents a statistically derived window — anywhere within it is considered ideal. Many health professionals suggest targeting the lower half of the range for Asian adults, given the HPB Singapore BMI recommendation of 18.5–22.9 and associated visceral fat considerations. However, the most important targets are your individual health markers — blood pressure, fasting glucose, and cholesterol — not a number on a scale.
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