Ideal Weight Calculator by Height and Sex
There's no single 'ideal weight': it depends on your bone structure, body composition (fat vs. muscle), age, and genetics. This calculator gives you the three most-used formulas in medicine: Devine (1974) — the most common for drug dosing —, Robinson (1983) — a more conservative refinement —, and Lorentz — popular for simplicity. It also shows the WHO healthy BMI range (18.5 to 24.9), the official range used by health authorities. A muscular athlete can be above this range and be totally healthy; a sedentary older adult can fall within range and have high visceral fat. Always supplement with body composition measurements (circumferences, skinfolds, or body fat %) and medical evaluation.
When to use this calculator
- You want to know if your weight falls within the WHO healthy range.
- You came back from a doctor's visit where they mentioned an 'ideal weight' and you want to see how it's calculated.
- You're a physician/pharmacist and need ideal weight for drug dosing.
- You're setting up a weight loss or gain plan and want a realistic target.
- You want to compare different formulas before setting a weight goal.
Example: 165 cm woman
- Devine:
45.5 + 2.3 × ((165 − 152) / 2.54)=45.5 + 2.3 × 5.12= 57.3 kg. - Robinson:
49 + 1.7 × 5.12= 57.7 kg. - Lorentz:
(165 − 100) − (165 − 150) / 2.5=65 − 6= 59 kg. - Average:
(57.3 + 57.7 + 59) / 3≈ 58 kg. - WHO BMI range:
18.5 × 1.65²= 50.4 kg (min);24.9 × 1.65²= 67.8 kg (max).
How it works
2 min readThe 3 Main Formulas
Devine (1974) — most used in medicine
Created by Dr. B.J. Devine to calculate antibiotic doses. It's the reference in clinical pharmacology.
Men:
Ideal weight (kg) = 50 + 2.3 × ((height_cm − 152.4) / 2.54)Women:
Ideal weight (kg) = 45.5 + 2.3 × ((height_cm − 152.4) / 2.54)(Subtracting 152.4 cm / 2.54 converts height into 'inches over 5 feet.')
Robinson (1983) — modern refinement
A revision of Devine with more recent data, slightly more conservative.
Men:
Ideal weight = 52 + 1.9 × ((height − 152.4) / 2.54)Women:
Ideal weight = 49 + 1.7 × ((height − 152.4) / 2.54)Lorentz — popular in Europe and Latin America
Very popular in European and Hispanic-American clinical practice for being simple and direct in centimeters.
Men:
Ideal weight = (height − 100) − (height − 150) / 4Women:
Ideal weight = (height − 100) − (height − 150) / 2.5Average Ideal Weight Table (kg)
| Height | Men (avg.) | Women (avg.) |
|---|---|---|
| 150 cm | — | 45–47 |
| 155 cm | 50–53 | 47–50 |
| 160 cm | 54–57 | 50–53 |
| 165 cm | 58–61 | 53–58 |
| 170 cm | 62–66 | 57–62 |
| 175 cm | 67–71 | 61–66 |
| 180 cm | 72–76 | 65–70 |
| 185 cm | 77–81 | — |
| 190 cm | 82–86 | — |
Healthy BMI Range (WHO)
The Body Mass Index (BMI) is the weight/height² ratio. The WHO classifies:
| BMI | Category |
|---|---|
| < 18.5 | Underweight |
| 18.5 – 24.9 | Normal weight |
| 25.0 – 29.9 | Overweight |
| 30.0 – 34.9 | Obesity grade I |
| 35.0 – 39.9 | Obesity grade II |
| ≥ 40.0 | Obesity grade III (morbid) |
Healthy Range Formula
Min weight = 18.5 × height_m²
Max weight = 24.9 × height_m²Limitations of Weight and BMI
Weight Does NOT Reflect Body Composition
A 180 cm, 95 kg bodybuilder has BMI 29.3 (overweight per WHO) but might have 8% body fat, high muscle mass, and excellent metabolic health. A sedentary 165 cm, 60 kg person has BMI 22 (normal) but may have 32% fat and metabolic syndrome.
Cases Where BMI Fails
Recommended Complementary Measurements
1. Waist circumference (crucial for cardiovascular risk):
- Men: < 94 cm low, 94–102 cm moderate, > 102 cm high.
- Women: < 80 cm low, 80–88 cm moderate, > 88 cm high.
2. Body fat % (US Navy, bioimpedance, DEXA).
3. Waist/hip ratio: men <0.95, women <0.85.
4. Lab work: glucose, lipid profile, HbA1c, fatty liver.
5. Blood pressure.
Common Mistakes
1. Obsessing over a number: ±3 kg around ideal weight is normal and depends on hydration, glycogen, menstrual cycle.
2. Using only BMI: gives false positives/negatives in athletes, elderly, children.
3. Weighing at different times daily: weight varies 1–2 kg throughout the day. Weigh yourself fasting, same scale.
4. Ignoring waist: two people with the same BMI can have very different metabolic risk based on visceral fat.
Frequently asked questions
Which of the 3 formulas is correct?
None is 'the correct one': each was created for different contexts. Devine is used in pharmacology (dosing antibiotics, anesthetics, chemotherapy); Robinson in epidemiological studies; Lorentz in general European clinical practice. The average of the 3 gives a reasonable reference value for personal use.
How much should I weigh if I'm 1.70 m (5'7")?
According to the WHO healthy range (BMI 18.5–24.9), between 53.5 kg and 72 kg. The average ideal weight from the 3 formulas is 62–66 kg for men and 57–62 kg for women. Any value within the range can be healthy depending on your body composition, activity level, and age.
Does BMI work for athletes?
Not reliably. A bodybuilder with 8% body fat can have a BMI of 29 (overweight category) and be healthier than a sedentary person with BMI 23. For athletes, body fat percentage and the waist/hip ratio are much better indicators.
How do I know my bone structure?
Measure your wrist circumference (cm) and compare to your height. Men: wrist < 16 cm = small; 16–18 cm = medium; > 18 cm = large. Women: < 14 cm = small; 14–16 cm = medium; > 16 cm = large. Elbow width with calipers also works.
Why aren't there exact formulas for children?
Because children grow fast and have different proportions at different ages. Pediatrics uses age- and sex-adjusted percentiles (WHO 2006), which are more sensitive.
Can I be above the WHO range and be healthy?
Yes, especially if you have high muscle mass and low body fat %. To assess, combine BMI with: (1) waist circumference, (2) body fat %, (3) metabolic lab work. Consult a physician for a full evaluation.
At what age should I worry about weight?
Body composition matters at any age, but priorities shift: (1) teens and young adults: prevent early overweight; (2) adults 30–50: watch visceral fat and metabolic health; (3) 60+: avoid sarcopenia (muscle loss) and being underweight. In older adults, mild overweight (BMI 25–27) is associated with lower mortality than 'normal weight.'
What's a healthy weight loss rate?
The WHO recommends losing 0.5 to 1 kg per week as the max sustainable and healthy rate. More than that causes muscle loss, nutritional deficits, and rebound. A moderate caloric deficit plan + strength training is ideal. These values are guidelines; consult a physician or dietitian.