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Discover your healthy weight range with our free ideal weight calculator, based on four classic medical formulas — Devine, Robinson, Miller and Hamwi.
Select your gender and enter your height in cm. The calculator converts to inches and runs four classic medical formulas — Devine, Robinson, Miller and Hamwi — then shows the full range across all four.
Formula: All four are linear in height above 5 feet: base + slope × (inches − 60). Devine (men): 50 + 2.3×(in−60); Robinson: 52 + 1.9×(in−60); Miller: 56.2 + 1.41×(in−60); Hamwi: 48 + 2.7×(in−60) (women’s bases differ).
Finding your healthy weight range takes two inputs and a single click. Follow these steps to get a result you can trust and act on.
Tip: re-check your height yearly if you are under 25 or over 50. Posture changes and spinal compression can shift height by a centimeter or two, which moves every formula’s answer.
Ideal weight is an estimate of the body weight associated with the best health outcomes and lowest mortality risk for your height and sex. It is not a beauty standard and not a performance target; it is a statistical concept built from large population studies, most famously the Metropolitan Life Insurance tables of the mid-20th century, and later refined into simple height-based formulas that doctors could compute at the bedside.
The key idea is that weight only means something relative to height. A 70 kg person who is 178 cm tall has a BMI of 22.1, comfortably healthy, while the same 70 kg at 160 cm gives a BMI of 27.3, in the overweight category. The ideal weight formulas capture this relationship with a strikingly simple structure: a base weight at five feet tall, plus a fixed number of kilograms for every inch above five feet. For men the Robinson formula uses 52 kg + 1.9 kg per inch; for women 49 kg + 1.7 kg per inch.
Why do the four formulas disagree? Because they were built for different purposes. Devine’s formula (1974) was created to dose medications safely, so it is the most cited in medicine. Robinson’s and Miller’s (both 1983) tried to improve on Devine using better body-composition data. Hamwi’s (1964) came from diabetes care. Each chose a slightly different base and slope, which is why a 178 cm man gets 73.2 kg from Devine but 70.4 kg from Miller. The calculator shows all four precisely so you see the uncertainty instead of hiding it.
Ideal weight is best used as a screening tool, not a verdict. It does not know your frame size, your muscle mass, your age, or your ethnicity, all of which shift healthy weight meaningfully. Use it to set a sensible target range, then refine that range with BMI, waist measurements, and how you actually feel and perform.
All four classic formulas share one structure: ideal weight = base + slope × (height in inches − 60), where 60 inches is five feet. Here are the exact equations:
Robinson (1983): men: 52 + 1.9 × (in − 60); women: 49 + 1.7 × (in − 60)
Miller (1983): men: 56.2 + 1.41 × (in − 60); women: 53.1 + 1.36 × (in − 60)
Devine (1974): men: 50 + 2.3 × (in − 60); women: 45.5 + 2.3 × (in − 60)
Hamwi (1964): men: 48 + 2.7 × (in − 60); women: 45.5 + 2.2 × (in − 60)
Notice the pattern: Miller starts from the highest base but climbs most slowly, while Hamwi starts lowest for men but climbs fastest, which is why Hamwi gives the highest answer for tall men. Two fully worked examples follow.
Worked example 1 (man): height 178 cm. Convert to inches: 178 ÷ 2.54 = 70.08 in. Inches over five feet: 70.08 − 60 = 10.08. Robinson: 52 + 1.9 × 10.08 = 52 + 19.15 = 71.1 kg. Miller: 56.2 + 1.41 × 10.08 = 56.2 + 14.21 = 70.4 kg. For completeness, Devine gives 50 + 2.3 × 10.08 = 73.2 kg and Hamwi gives 48 + 2.7 × 10.08 = 75.2 kg. The full range is 70.4–75.2 kg, matching the calculator’s own default output exactly.
Worked example 2 (woman): height 165 cm. Convert: 165 ÷ 2.54 = 64.96 in. Inches over five feet: 64.96 − 60 = 4.96. Robinson: 49 + 1.7 × 4.96 = 49 + 8.43 = 57.4 kg. Miller: 53.1 + 1.36 × 4.96 = 53.1 + 6.75 = 59.8 kg. Devine gives 45.5 + 2.3 × 4.96 = 56.9 kg and Hamwi gives 45.5 + 2.2 × 4.96 = 56.4 kg, so her range is 56.4–59.8 kg. Observe how the women’s slopes are gentler than the men’s, reflecting lower average muscle mass per inch of height.
A useful mental shortcut: for men, Robinson adds roughly 1.9 kg per 2.54 cm (one inch) above 152 cm, so each centimeter above five feet is worth about 0.75 kg. You can sanity-check any result with that rule of thumb.
Daniel is 178 cm tall and currently weighs 85 kg. The calculator gives him an ideal range of 70.4–75.2 kg. Subtracting, he needs to lose between 9.8 kg (to reach the top of the range) and 14.6 kg (to reach the bottom). Rather than fixing on one number, he sets a staged goal: first reach 75 kg, then reassess how he looks and feels before deciding whether to continue toward 72 kg.
At a sustainable loss rate of 0.5 kg per week, the first stage (10 kg) takes about 20 weeks, and the full journey to the bottom of the range (14.6 kg) takes about 29 weeks. That timeline demands a daily deficit of roughly 550 kcal (0.5 kg of fat ≈ 3,850 kcal per week). Daniel builds it from both sides: he trims about 350 kcal from his diet and adds a 200 kcal daily walk, which our Calories Burned Calculator shows is roughly 35 minutes of brisk walking at his weight.
The practical lesson: the calculator converts a vague wish (“lose weight”) into an engineered plan, 10 kg over 20 weeks via a 550 kcal daily deficit, with a built-in review point. Daniel also strength-trains twice weekly so the weight he loses is fat, not muscle, and he re-runs the calculator every two months, not because his height changed, but to recompute his targets as his weight drops.
Priya is 165 cm tall and weighs 70 kg. The calculator gives her an ideal range of 56.4–59.8 kg. To cross-check, she computes her BMI: 70 ÷ (1.65 × 1.65) = 70 ÷ 2.7225 = 25.7, just into the overweight category (25.0+). The two tools agree: she is above her healthy zone.
She sets her target at 58 kg, the middle of her ideal range. At 58 kg her BMI becomes 58 ÷ 2.7225 = 21.3, comfortably inside the healthy 18.5–24.9 band. Note the relationship: the BMI healthy range for her height spans 50.4–67.8 kg (18.5 × 2.7225 to 24.9 × 2.7225), much wider than the 56.4–59.8 kg formula range. The formulas give a tighter, more actionable target; BMI gives the outer safety rails. Using both, Priya knows that anything under 67.8 kg is medically acceptable, but 56–60 kg is her evidence-based sweet spot.
She needs to lose 12 kg. At 0.5 kg per week that is 24 weeks, a six-month project. She also measures her waist monthly, because if her waist shrinks while her weight plateaus, she is likely gaining muscle as she loses fat, and the scale alone would mislead her. When she reaches 58 kg she will verify with a body fat measurement rather than celebrating the number alone.
1. Treating one formula’s output as a precise prescription. The four methods disagree by up to 5 kg for the same person. Anyone who fixates on “71.1 kg exactly” is mistaking a statistical estimate for a physical constant. Work with the full range the calculator shows and aim for its middle or upper half if you are muscular.
2. Ignoring frame size and muscle mass. The formulas assume a medium frame and average muscularity. A broad-shouldered lifter can be perfectly healthy 5 kg above his range, while a slight-framed sedentary person may be healthiest at the bottom of hers. Adjust by about ±10% for small or large frames: 71.1 kg becomes roughly 64 kg or 78 kg.
3. Applying the formulas to children, teenagers, or the frail elderly. They were calibrated on adults around five feet and taller. Growing adolescents need pediatric growth charts, and older adults often benefit from slightly higher weight that protects against frailty and falls. The calculator is an adult tool.
4. Confusing ideal weight with the BMI range. For a 178 cm man, the BMI healthy range is 58.6–78.9 kg, far wider than the 70.4–75.2 kg formula range. BMI tells you the broad zone where risk stays low; the formulas suggest where within (or near) that zone to aim. Both are useful, and neither replaces a body-fat reading.
5. Crash-dieting to hit the number fast. Losing 2 kg a week to reach your ideal weight in a month costs you muscle, tanks your energy, and nearly guarantees rebound. The evidence-based rate is 0.5–1 kg per week through a moderate calorie deficit plus resistance training. Your ideal weight will still be there in six months; arrive with your muscle and metabolism intact.
This page provides a free ideal weight calculator using four classic formulas, all linear in height above 5 feet: Devine (men 50+2.3×(in−60); women 45.5+2.3×(in−60)), Robinson (men 52+1.9×(in−60); women 49+1.7×(in−60)), Miller (men 56.2+1.41×(in−60); women 53.1+1.36×(in−60)), and Hamwi (men 48+2.7×(in−60); women 45.5+2.2×(in−60)). Worked examples: a 178 cm man gets Robinson 71.1 kg and Miller 70.4 kg (range 70.4–75.2 kg); a 165 cm woman gets Robinson 57.4 kg and Miller 59.8 kg (range 56.4–59.8 kg). Practical cases cover an 85 kg man planning a 20–29 week fat-loss roadmap and a 70 kg woman cross-checking BMI 25.7 against her 56.4–59.8 kg range. The page explains ideal weight concepts, formula origins, frame-size adjustment (±10%), and five common mistakes.
A 178 cm man lands around 70–75 kg across the four classic formulas. Enter your height above for your personal range.
Devine is the most cited in medicine; the range across all four is more honest than any single number.
They’re related but different: BMI healthy range (18.5–24.9) for 178 cm is 58.6–78.9 kg — much wider.
Not well — muscular people can exceed their “ideal” weight while being very lean. Pair this with the body fat calculator.
Women naturally carry more essential fat and typically less muscle mass at the same height.
The Hamwi formula (1964) was developed for clinical nutrition and medication dosing, estimating a healthy weight as 48 kg + 2.7 kg per inch over 5 feet for men, and 45.5 kg + 2.2 kg per inch over 5 feet for women. It gives the highest estimate of the four for tall men (75.2 kg for a 178 cm man) because of its steep 2.7 kg/inch slope. It is still used in hospitals today for drug-dosage calculations.
No. All four formulas were calibrated on adults at least 5 feet (152 cm) tall, and their linear structure breaks down below that: subtracting inches under 60 from the base weight produces unrealistically low or even nonsensical numbers. Children and teenagers should use pediatric growth charts, and shorter adults are better served by BMI ranges and body-fat measurements than by extrapolated formula values.
Yes, roughly. The formulas assume a medium frame. A common rule: subtract about 10% for a small frame and add about 10% for a large frame. For example, a Robinson result of 71.1 kg becomes roughly 64.0 kg for a slight-framed person or 78.2 kg for a broad-framed one. You can gauge frame size by wrist circumference: under about 16 cm at average height suggests a small frame; over 18 cm suggests a large frame.
Also try our BMI Calculator, Body Fat Calculator and BMR Calculator — or browse all Fitness & Health Calculators.
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