Free online Ideal Body Weight Calculator
IBW Calculator
Ideal Body Weight Calculator
Calculate your ideal weight based on multiple scientific formulas
What is IBW?
- Definition: IBW is the weight considered optimal for health, longevity, and reduced risk of disease, based on population averages.
- Use Cases:
- Medical dosing (especially for certain drugs).
- Baseline for nutrition and fitness planning.
- Quick screening alongside BMI and body fat %.
Common IBW Formulas (USA Clinical Practice)
Several formulas are used in American hospitals and clinics. Here are the most cited ones:
| Formula | Men | Women | Notes |
|---|---|---|---|
| Devine (1974) | 50 kg + 2.3 kg per inch over 5 ft | 45.5 kg + 2.3 kg per inch over 5 ft | Widely used in medicine (drug dosing). |
| Hamwi (1964) | 106 lbs + 6 lbs per inch over 5 ft | 100 lbs + 5 lbs per inch over 5 ft | Simple, older formula. |
| Robinson (1983) | 52 kg + 1.9 kg per inch over 5 ft | 49 kg + 1.7 kg per inch over 5 ft | Adjusted for modern populations. |
| Miller (1983) | 56.2 kg + 1.41 kg per inch over 5 ft | 53.1 kg + 1.36 kg per inch over 5 ft | Slightly lower estimates. |
(1 inch = 2.54 cm; 1 kg ≈ 2.2 lbs)
Example: 5’10” (178 cm) Adult
- Devine (male): 50 + (2.3 × 10) = 73 kg ≈ 160 lbs
- Hamwi (male): 106 + (6 × 10) = 166 lbs
- Robinson (male): 52 + (1.9 × 10) = 71 kg ≈ 156 lbs
- Miller (male): 56.2 + (1.41 × 10) = 70.3 kg ≈ 155 lbs
So, for a 5’10” male, IBW ranges 155–166 lbs depending on formula.
Healthy BMI Range (USA Standard)
- BMI 18.5–24.9 is considered “healthy.”
- For 5’10” (178 cm):
- Lower bound: 129 lbs (BMI 18.5).
- Upper bound: 174 lbs (BMI 24.9).
This overlaps with IBW formulas, showing consistency.
USA Context
- Clinical Use: Devine formula is most common in hospitals.
- Public Health: BMI is more widely used for population health.
- Fitness Industry: IBW is often combined with body fat % for precision.
Strategic Insights
- IBW is not absolute: athletes with high muscle mass may weigh more but still be healthy.
- Frame size (wrist circumference, bone density) can shift IBW up or down.
- Better metrics: Waist-to-height ratio, body fat %, and metabolic health are often more predictive than IBW alone.
FAQs
Q: What is the most used IBW formula in the USA? A: The Devine formula is most common in clinical medicine.
Q: How is IBW different from BMI? A: IBW gives a target weight based on height and sex; BMI is a ratio of weight to height squared.
Q: Can IBW be inaccurate? A: Yes — it doesn’t account for muscle mass, ethnicity, or body composition.
Q: What’s a healthy weight for a 5’5” woman in the USA? A: Depending on formula, ~115–135 lbs; BMI range ~114–150 lbs.