⚖️ Ideal Weight Calculator
Find your ideal body weight using four clinically established formulas — Devine, Robinson, Miller & Hamwi — plus the healthy BMI weight range for your height.
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4 Formulas
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💡 These formulas were developed for adults and work best for heights above 5 ft (152 cm). Results are reference ranges — not medical advice.
Average Ideal Weight (all formulas)
· · Range:
Lowest Est.
Average
all 4 formulas
Highest Est.
BMI Range
BMI 18.5–24.9
Formula Results
Healthy Weight Range (BMI 18.5 – 24.9)
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To reach the average ideal weight:
💡 You are above the average ideal weight.
At a healthy deficit of 500 kcal/day (~1 lb/week), it would take approximately
to reach it.
💡 You are below the average ideal weight.
A gradual surplus of 300–500 kcal/day can help you gain weight healthily.
🎉 Your current weight matches the average ideal weight perfectly!
Formula Comparison
BMI Range Midpoint
Formula Reference
| Formula | Year | Male (kg) | Female (kg) | Notes |
|---|---|---|---|---|
| Devine | 1974 | 50 + 2.3×(H−60) | 45.5 + 2.3×(H−60) | H in inches over 5 ft |
| Robinson | 1983 | 52 + 1.9×(H−60) | 49 + 1.7×(H−60) | Revised Devine |
| Miller | 1983 | 56.2 + 1.41×(H−60) | 53.1 + 1.36×(H−60) | Revised Devine |
| Hamwi | 1964 | 48 + 2.7×(H−60) | 45.5 + 2.2×(H−60) | Oldest formula |
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4 Formulas
Devine, Robinson, Miller & Hamwi with side-by-side comparison
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BMI Range
Healthy weight window based on BMI 18.5–24.9
🎯
Average
Average across all formulas for a balanced estimate
📏
Any Height
Works for metric (cm) and imperial (ft/in) inputs
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Current Weight
Optional: compare your weight to the ideal range
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Reference Table
All formula equations explained clearly
📐 Devine Formula (most widely used)
Male: IBW = 50 kg + 2.3 kg × (each inch over 5 ft)
Female: IBW = 45.5 kg + 2.3 kg × (each inch over 5 ft)
Robinson, Miller & Hamwi use the same structure with different constants.
Four formulas, all built on height above five feet
Each of the four formulas shares the same structure: a base weight for someone exactly five feet tall, plus a fixed increment for every inch above that. They differ only in the constants, which is why they disagree by a few kilograms for the same person. The calculator converts your height into inches, subtracts 60, and applies each formula in turn.
Hamwi, published in 1964, uses a base of 48.0 kg for men plus 2.7 kg per inch, and 45.5 kg for women plus 2.2 kg per inch. Devine, from 1974, uses 50.0 kg plus 2.3 kg per inch for men and 45.5 kg plus 2.3 kg per inch for women. Robinson, from 1983, uses 52 kg plus 1.9 kg per inch for men and 49 kg plus 1.7 kg per inch for women. Miller, also 1983, uses 56.2 kg plus 1.41 kg per inch for men and 53.1 kg plus 1.36 kg per inch for women.
The healthy BMI range is calculated separately. BMI is weight in kilograms divided by height in metres squared, so multiplying your height in metres squared by 18.5 and by 24.9 gives the lower and upper weights of the conventional healthy band.
Hamwi, published in 1964, uses a base of 48.0 kg for men plus 2.7 kg per inch, and 45.5 kg for women plus 2.2 kg per inch. Devine, from 1974, uses 50.0 kg plus 2.3 kg per inch for men and 45.5 kg plus 2.3 kg per inch for women. Robinson, from 1983, uses 52 kg plus 1.9 kg per inch for men and 49 kg plus 1.7 kg per inch for women. Miller, also 1983, uses 56.2 kg plus 1.41 kg per inch for men and 53.1 kg plus 1.36 kg per inch for women.
The healthy BMI range is calculated separately. BMI is weight in kilograms divided by height in metres squared, so multiplying your height in metres squared by 18.5 and by 24.9 gives the lower and upper weights of the conventional healthy band.
Worked example: a man of 178 cm weighing 84 kg
A height of 178 cm is 70.08 inches, which is 10.08 inches above five feet.
Devine gives 50.0 plus 2.3 times 10.08, which is 50.0 plus 23.2, or 73.2 kg. Robinson gives 52 plus 1.9 times 10.08, which is 52 plus 19.2, or 71.2 kg. Miller gives 56.2 plus 1.41 times 10.08, which is 56.2 plus 14.2, or 70.4 kg. Hamwi gives 48.0 plus 2.7 times 10.08, which is 48.0 plus 27.2, or 75.2 kg. The four add up to 290.0 kg, so the average ideal weight is 72.5 kg, a spread of just under 5 kg between the highest and lowest estimate.
For the BMI band, 1.78 metres squared is 3.1684. Multiplying by 18.5 gives 58.6 kg and by 24.9 gives 78.9 kg, so the healthy range runs from roughly 59 kg to 79 kg, with a midpoint near 68.8 kg.
A current weight of 84 kg sits 11.5 kg above the 72.5 kg average and about 5 kg above the top of the BMI band. At a steady 0.5 kg per week, closing the 11.5 kg gap would take around 23 weeks.
Devine gives 50.0 plus 2.3 times 10.08, which is 50.0 plus 23.2, or 73.2 kg. Robinson gives 52 plus 1.9 times 10.08, which is 52 plus 19.2, or 71.2 kg. Miller gives 56.2 plus 1.41 times 10.08, which is 56.2 plus 14.2, or 70.4 kg. Hamwi gives 48.0 plus 2.7 times 10.08, which is 48.0 plus 27.2, or 75.2 kg. The four add up to 290.0 kg, so the average ideal weight is 72.5 kg, a spread of just under 5 kg between the highest and lowest estimate.
For the BMI band, 1.78 metres squared is 3.1684. Multiplying by 18.5 gives 58.6 kg and by 24.9 gives 78.9 kg, so the healthy range runs from roughly 59 kg to 79 kg, with a midpoint near 68.8 kg.
A current weight of 84 kg sits 11.5 kg above the 72.5 kg average and about 5 kg above the top of the BMI band. At a steady 0.5 kg per week, closing the 11.5 kg gap would take around 23 weeks.
What the number can and cannot tell you
These formulas were not designed as body-image targets. Devine's equation was introduced to calculate drug dosages, and the others were developed in similar clinical and insurance contexts. They take only height and sex as inputs, which means they say nothing about your frame size, muscle mass, bone density, age or body composition. A muscular athlete can sit far above all four figures while carrying little fat, and someone within the range can still carry a high proportion of it.
The spread between the four results is itself informative. Where they differ by several kilograms for the same height, no single value should be treated as a precise goal. Read the range they form, and the healthy BMI band alongside it, as a broad orientation rather than a target weight.
The weekly projection assumes a steady half-kilogram change, which is a commonly cited moderate rate, but real progress is rarely linear and plateaus are normal. Do not use these figures to set a restrictive plan on your own. If weight is a health concern, speak to a doctor or dietitian, who can account for factors a height-based formula cannot. This tool provides general information and is not medical advice.
The spread between the four results is itself informative. Where they differ by several kilograms for the same height, no single value should be treated as a precise goal. Read the range they form, and the healthy BMI band alongside it, as a broad orientation rather than a target weight.
The weekly projection assumes a steady half-kilogram change, which is a commonly cited moderate rate, but real progress is rarely linear and plateaus are normal. Do not use these figures to set a restrictive plan on your own. If weight is a health concern, speak to a doctor or dietitian, who can account for factors a height-based formula cannot. This tool provides general information and is not medical advice.
Frequently Asked Questions
None of them individually. Devine is the most widely cited, largely because of its clinical use in dosing, but Robinson and Miller were later revisions intended to improve on it, and Hamwi is the oldest. The calculator shows all four plus their average precisely so you read the range rather than a single figure.
They share the same structure but use different base weights and per-inch increments, drawn from different populations and purposes. At 178 cm the four results here span about 5 kg, from 70.4 kg to 75.2 kg. That spread reflects genuine uncertainty in the underlying method, not an error in any one formula.
BMI is weight in kilograms divided by height in metres squared. Multiplying your height in metres squared by 18.5 and 24.9 produces the weights at each end of the conventional healthy band. At 1.78 metres that is about 59 kg to 79 kg, which is usually wider than the formula results.
No. Every one of these formulas uses only height and biological sex, so a muscular athlete and a sedentary person of the same height receive the same figure. Measures such as waist circumference, body fat percentage or a DEXA scan give a far better picture of body composition.
It is better treated as a reference point than a goal. These equations originated in clinical settings, mainly for medication dosing and insurance tables, not for personal weight targets. Any decision about changing your weight is worth discussing with a doctor or registered dietitian who knows your history.