Adult BMI + Healthy Weight Range Calculator
Compute BMI, BMI category, and the weight range that would put you in the healthy 18.5–24.9 band, plus three alternative ideal-weight formulas (Devine, Robinson, Miller).
Normal
- Devine (1974): 73.0 kg (160.9 lb)
- Robinson (1983): 71.0 kg (156.5 lb)
- Miller (1983): 70.3 kg (155.0 lb)
BMI categories per WHO 1995/2000, adopted by CDC and NIH. Healthy weight range = 18.5–24.9 × height². Ideal-weight formulas: Devine BJ, Drug Intell Clin Pharm 1974;8:650 (drug dosing); Robinson JD et al., Am J Hosp Pharm 1983;40:1016; Miller DR et al., Drug Intell Clin Pharm 1983;17:233. BMI is a screening tool only — pair with waist circumference (NIH 2018) and body composition for individual assessment.
General calculation reads
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About this tool
Body Mass Index = weight (kg) / height² (m²). The WHO categories (also adopted by CDC and NIH) are: underweight < 18.5; normal 18.5–24.9; overweight 25.0–29.9; obesity class I 30.0–34.9; class II 35.0–39.9; class III ≥ 40.0. The "healthy weight range" is the weight band that puts BMI in 18.5–24.9 at a given height. BMI was popularized as a population screening tool by Ancel Keys (1972) and is not a body composition measure — athletes and muscular builds register as overweight while frail elderly may register as normal weight despite low lean mass. For individual diagnosis, BMI is paired with waist circumference (NIH 2018 guideline: ≥ 102 cm men / 88 cm women indicates increased cardiometabolic risk independent of BMI) or with body fat percentage. Alternative "ideal body weight" formulas predate BMI and remain in clinical use for drug dosing: Devine (1974): 50 kg (men) / 45.5 kg (women) + 2.3 kg per inch over 5 ft; Robinson (1983): 52 / 49 + 1.9 per inch; Miller (1983): 56.2 / 53.1 + 1.41 per inch. These give a single point estimate rather than a range.
How to use it
- Enter your height and weight in either US or metric units.
- Read your BMI, WHO category, and the weight range that would put you in the healthy 18.5–24.9 band.
- Compare with the three classic ideal-weight formulas (Devine / Robinson / Miller).
- For waist circumference cutoffs and body-composition context, consult a physician.
Frequently asked questions
- Is BMI accurate for everyone?
- No — it does not distinguish muscle from fat. Athletes, bodybuilders, and people of South Asian or East Asian descent may have higher health risk at lower BMIs (WHO Asian-Pacific cutoffs lower the overweight threshold to 23).
- Which "ideal weight" formula is right?
- There is no single right answer; all three are used in clinical drug-dosing depending on context. Devine is most common in adult medicine; Robinson is common in pediatrics; Miller is used for some cardiovascular drugs.
- What about waist circumference?
- NIH 2018 guidelines flag waist ≥ 40" (102 cm) for men or ≥ 35" (88 cm) for women as a risk factor independent of BMI. Use both for a better picture.
- Does BMI predict mortality?
- Population studies (NHANES, Whitehall) show a J-shaped curve with lowest all-cause mortality around BMI 22–25 for adults under 65. Above 65, the optimum shifts up to 27–29.
- Is data sent anywhere?
- No. All math runs in your browser.