What is ideal body weight?
Ideal body weight (IBW) is an estimate of a healthy weight for your height and sex. The formulas were first created by doctors to calculate medicine doses, but today they are widely used as a quick guide for setting a weight goal. There is no single perfect weight for anyone — a healthy weight is a range, and the right point within it depends on your frame size, muscle mass, age and health.
That is why this ideal weight calculator shows four classic formulas side by side together with the healthy BMI range for your height.
How the ideal weight calculator works
Each formula starts with a base weight at 5 feet (152.4 cm) and adds a fixed amount for every inch above that:
| Formula | Men | Women |
|---|---|---|
| Robinson (1983) | 52 kg + 1.9 kg per inch over 5 ft | 49 kg + 1.7 kg per inch over 5 ft |
| Miller (1983) | 56.2 kg + 1.41 kg per inch | 53.1 kg + 1.36 kg per inch |
| Devine (1974) | 50 kg + 2.3 kg per inch | 45.5 kg + 2.3 kg per inch |
| Hamwi (1964) | 48 kg + 2.7 kg per inch | 45.5 kg + 2.2 kg per inch |
The healthy BMI range is calculated as 18.5 × height (m)² to 24.9 × height (m)². For people of South Asian, East Asian or Arab heritage, a range of 18.5–22.9 is often more appropriate.
Example: a man 180 cm tall (70.9 inches, so 10.9 inches over 5 ft) has a Devine ideal weight of 50 + 2.3 × 10.9 ≈ 75 kg, and a healthy BMI range of 59.9–80.7 kg.
Ideal weight chart by height
Healthy weight ranges (BMI 18.5–24.9) for common heights, for both women and men:
| Height | Underweight below | Healthy range | Overweight above |
|---|---|---|---|
| 150 cm (4′11″) | 41.6 kg | 41.6 – 56.0 kg | 56.0 kg |
| 155 cm (5′1″) | 44.4 kg | 44.4 – 59.8 kg | 59.8 kg |
| 160 cm (5′3″) | 47.4 kg | 47.4 – 63.7 kg | 63.7 kg |
| 165 cm (5′5″) | 50.4 kg | 50.4 – 67.8 kg | 67.8 kg |
| 170 cm (5′7″) | 53.5 kg | 53.5 – 72.0 kg | 72.0 kg |
| 175 cm (5′9″) | 56.7 kg | 56.7 – 76.3 kg | 76.3 kg |
| 180 cm (5′11″) | 59.9 kg | 59.9 – 80.7 kg | 80.7 kg |
| 185 cm (6′1″) | 63.3 kg | 63.3 – 85.2 kg | 85.2 kg |
| 190 cm (6′3″) | 66.8 kg | 66.8 – 89.9 kg | 89.9 kg |
Benefits of knowing your ideal weight
- A realistic goal based on medical formulas rather than unrealistic social media images.
- Lower health risks: staying within a healthy range reduces the risk of type 2 diabetes, high blood pressure, joint pain and some cancers.
- Better planning: once you know your target, the weight loss calculator shows how long it may take.
- Motivation by milestones: you can break a big goal into smaller 5% steps.
Health warnings
- Ideal weight formulas do not consider muscle mass, frame size or body fat. Athletes may be healthy well above them.
- The formulas are less reliable for people shorter than 152 cm (5 ft) or very tall people.
- Not for children, teenagers or pregnant women — use the child BMI calculator or pregnancy weight gain calculator.
- For older adults (65+), a weight slightly above the range is often protective. Ask your doctor.
- Never aim for a weight below the healthy range.
How to reach your ideal weight
Move towards your goal slowly — around 0.25–0.5 kg a week. Use the calorie calculator to set your intake, build meals around vegetables, lean protein and wholegrains, and stay active every day. If you are underweight, read our guide to healthy weight gain.
Frequently asked questions
What is my ideal weight for my height?
Your healthy weight is a range. For most adults it is the weight that gives a BMI of 18.5–24.9 at your height. For example, at 165 cm the healthy range is about 50–68 kg. The calculator above gives your personal range.
Which ideal body weight formula is most accurate?
None is perfect. The Robinson and Miller formulas often give more realistic results for women and shorter people, while Devine is the one most used in hospitals. Looking at all of them alongside the BMI range is the best approach.
Is ideal weight different for women and men?
Yes. The formulas give women a lower ideal weight than men of the same height, because women usually have less muscle and a smaller frame. The healthy BMI range is the same for both.
Does ideal weight change with age?
The formulas do not change with age, but many experts accept a slightly higher weight in older adults because it may protect against frailty and bone loss.
I am muscular — does my ideal weight still apply?
Not fully. Muscle is heavy, so muscular people can be healthy above the formula weight. A body fat percentage or waist measurement is a better guide for you.
Sources
- Devine BJ. Gentamicin therapy. Drug Intell Clin Pharm 1974;8:650–655.
- Robinson JD, et al. Determination of ideal body weight for drug dosage calculations. Am J Hosp Pharm 1983;40:1016–1019.
- Miller DR, et al. Am J Hosp Pharm 1983.
- Hamwi GJ. Therapy: changing dietary concepts. 1964.
- WHO BMI classification.