Ideal Weight for Your Height – Complete Guide
Short answer: There is no single 'ideal' body weight — there is a healthy range, and several clinical formulas that pick a specific point inside or near that range for reference purposes.
What the evidence says
The BMI-based healthy range (BMI 18.5–24.9 multiplied by height squared) is the most common definition. It gives a band roughly 15–20 kg wide for a typical adult height.
The Devine formula (1974) was designed for medication dosing and gives a single number: 50 kg for a man of 60 inches plus 2.3 kg per additional inch, and 45.5 kg + 2.3 kg per inch for women. It tends to run low for tall or muscular people.
The Robinson (1983) and Hamwi formulas offer refinements. In practice, use the BMI range as the honest answer, and treat the single-number formulas as reference points, not targets.
This range corresponds to the lowest statistical risk of cardiovascular disease, type 2 diabetes, and metabolic syndrome in long-term cohort studies.
WHO adult BMI categories
The World Health Organization defines adult BMI categories using the following thresholds. These apply to adults 18–65 and are not adjusted for sex, ethnicity, or athletic status.
| Category | BMI | Population signal |
|---|---|---|
| Underweight | < 18.5 | Screen for nutritional or clinical cause |
| Normal weight | 18.5 – 24.9 | Lowest all-cause mortality band |
| Overweight | 25.0 – 29.9 | Moderate risk; strongly modified by fitness |
| Obese Class I | 30.0 – 34.9 | Clinically meaningful cardiometabolic risk |
| Obese Class II | 35.0 – 39.9 | Structured treatment usually recommended |
| Obese Class III | ≥ 40.0 | Multidisciplinary care indicated |
The BMI formula (and how this site rounds it)
Metric: BMI = weight in kilograms ÷ (height in metres)². Imperial: BMI = 703 × weight in pounds ÷ (height in inches)². Both produce the same number; 703 is the unit-conversion constant.
Worked example. An adult weighing 95 kg at 185 cm: 185 cm = 1.85 m, and 1.85² = 3.4225. 95 ÷ 3.4225 = 27.8, which is overweight. The imperial route (209 lbs, 73 in) gives 703 × 209 ÷ 73² = 27.6 — the same value within rounding.
Rounding rules used here: BMI is rounded to one decimal place, and the WHO category is assigned from that rounded value. Weights in kilograms are shown to one decimal; pound equivalents are rounded to the nearest whole pound using 1 kg = 2.20462 lbs. Height in feet and inches is rounded to the nearest inch.
| Weight | Height | BMI | WHO category |
|---|---|---|---|
| 70 kg (154 lbs) | 175 cm (5'9") | 22.9 | Normal weight |
| 60 kg (132 lbs) | 165 cm (5'5") | 22.0 | Normal weight |
| 85 kg (187 lbs) | 180 cm (5'11") | 26.2 | Overweight |
| 55 kg (121 lbs) | 160 cm (5'3") | 21.5 | Normal weight |
| 78 kg (172 lbs) | 170 cm (5'7") | 27.0 | Overweight |
| 95 kg (209 lbs) | 185 cm (6'1") | 27.8 | Overweight |
Healthy weight range by height (adults 18–65)
| Height | Healthy weight (kg) | Healthy weight (lbs) |
|---|---|---|
| 155 cm (5'1") | 44.4–59.8 kg | 98–132 lbs |
| 160 cm (5'3") | 47.4–63.7 kg | 104–140 lbs |
| 165 cm (5'5") | 50.4–67.8 kg | 111–149 lbs |
| 170 cm (5'7") | 53.5–72 kg | 118–159 lbs |
| 175 cm (5'9") | 56.7–76.3 kg | 125–168 lbs |
| 180 cm (5'11") | 59.9–80.7 kg | 132–178 lbs |
| 185 cm (6'1") | 63.3–85.2 kg | 140–188 lbs |
| 190 cm (6'3") | 66.8–89.9 kg | 147–198 lbs |
What BMI does not measure
BMI uses only height and weight. It is a screening ratio, not a body-composition measurement or a diagnosis. Specifically, BMI cannot tell you:
- Muscle versus fat. Weight from muscle and weight from fat count identically, so trained athletes are frequently classified as overweight at healthy body-fat levels.
- Where fat is stored. Visceral (abdominal) fat carries far more cardiometabolic risk than subcutaneous fat, and BMI is blind to the difference. Waist circumference — under 94 cm for men, 80 cm for women — adds that missing signal.
- Bone density or hydration. Both shift scale weight without changing fat mass.
- Age-related body change. Muscle mass declines with age (sarcopenia), so the same BMI at 70 usually represents more fat than at 25.
Where adult BMI does not apply at all: children and teenagers under 18 (who need age-and-sex percentile charts, not adult thresholds), pregnant and breastfeeding women, people with significant oedema or ascites, and adults with limb loss or skeletal dysplasia. Population-specific cut-offs are also lower for South and East Asian adults, where the WHO recommends action points at BMI 23 and 27.5.
Practical next steps
Rather than aim for one number, aim for the middle of the BMI healthy range for your height, then evaluate against waist circumference (under 94 cm men / 80 cm women) and fitness capacity. That combined picture is a better health target than any single 'ideal weight' figure.
- Keep a stable routine of movement, sleep (7–9 h), and balanced meals.
- Add resistance training to slow age-related muscle loss.
- Watch the trend, not the daily fluctuation — month-over-month is what matters.
- Check blood pressure and cholesterol annually.
Frequently asked questions
Ideal Weight for Your Height – Complete Guide — what does the answer depend on?
The most direct answer comes from calculating BMI (weight in kg ÷ height in m²) and comparing the result against the WHO thresholds (18.5, 25, 30). Height, weight, sex, activity level, and waist circumference all refine the interpretation.
How accurate is BMI as a health signal?
BMI is a screening tool, not a diagnosis. It performs well as a population marker but can misclassify muscular or very lean individuals. Pairing BMI with waist circumference and routine bloodwork gives a much more reliable picture.
What is the healthy BMI range for adults?
The World Health Organization defines a healthy adult BMI as 18.5 to 24.9. Below 18.5 is underweight; 25 to 29.9 is overweight; 30 and above is obese, split into three clinical classes.
Should I use the calculator here?
Yes — the calculator on this page returns your BMI instantly, shows the category, and displays your healthy weight range in both kg and lbs. Nothing is uploaded or stored on a server.
How often should I recheck my BMI?
For most adults, once every 3–6 months is enough. Track waist circumference alongside — it often changes before scale weight and is a more sensitive early signal.