Ideal Weight Calculator
Calculate your ideal weight with three science-based methods — Devine, Robinson and the healthy BMI range. A realistic range, not one arbitrary number.
TL;DR
There's no single "ideal weight" — there's a healthy range. The most common reference is the BMI 18.5–24.9 band: 56.7–76.3 kg for someone 1.75 m tall. Enter your height and your range appears instantly.
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Is there really such a thing as an "ideal weight"?
Short answer: not as a single number, but yes as a range. Two people of the same height can have completely different muscle mass, bone structure and fat distribution. That's why this calculator shows the result of three methods and an overall healthy range instead of forcing one number on you.
The three methods used
- Devine formula (1974): men: 50 kg + 2.3 kg per inch over 152 cm; women: 45.5 kg + the same increment. Originally created for drug dosing, it's still used as a clinical reference today.
- Robinson formula (1983): an updated take on Devine. Men: 52 kg + 1.9 kg per inch; women: 49 kg + 1.7 kg per inch. Usually slightly more conservative than Devine.
- Healthy BMI range: the weight matching the WHO's 18.5–24.9
band:
lower = 18.5 × height²(m),upper = 24.9 × height²(m). You can check your current BMI with the BMI calculator.
Worked example: a man 175 cm tall
- Devine: 50 + 2.3 × 8.9 ≈ 70.5 kg
- Robinson: 52 + 1.9 × 8.9 ≈ 68.9 kg
- BMI range: 56.7 – 76.3 kg
Bottom line: anything from roughly 57 to 76 kg can be healthy for him, with the formula estimates clustering around 69–71 kg. If he carries a lot of muscle, even slightly above 76 kg may be fine — which is why waist circumference and body-fat percentage are better companions than the scale alone.
Outside the range? Here's what to do
- Above it: work out your daily calorie needs with the calorie calculator and start with a 15–20% deficit. A safe rate is 0.5–1 kg per week — the full method is in how many calories to lose weight.
- Below it: gain healthy weight with a small surplus (+10–15%) and 2–3 strength sessions a week — see the healthy weight gain guide.
Not medical advice. These formulas are screening tools; talk to a doctor or dietitian to set a personal target.
Frequently asked questions
What should my ideal weight be?
There is no single correct number — the scientific answer is a range. The most common reference is the weight matching a BMI of 18.5–24.9: for someone 1.75 m tall that's 56.7–76.3 kg. If you carry a lot of muscle, the upper end can still be healthy.
What is the Devine formula?
Developed in 1974 by Dr BJ Devine for drug dosing: for men, 50 kg plus 2.3 kg per inch over 152 cm; for women it starts at 45.5 kg. Practical, but it ignores body composition.
Why show a range instead of one number?
Two people of the same height can have very different muscle mass, bone structure and fat distribution. A muscular 178 cm athlete can be healthy at 85 kg, while a sedentary person at the same weight may carry excess fat.
How do I reach my ideal weight?
Above the range: eat 15–20% below your TDEE and train 2–3 times a week. Below it: use a small calorie surplus plus strength training. A safe rate of change is 0.5–1% of body weight per week.
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