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Ideal Weight Calculator: Scientific Formulas & Targets

Determine your ideal body weight. Learn about Devine, Robinson, and Hamwi formulas, and how frame size impacts targets.

Calculating your ideal body weight (IBW) involves reviewing standard medical formulas developed to estimate healthy target weights based on height, gender, and body frame parameters. These formulas are used in clinical settings to determine medication dosages and set weight goals.

Formula & Math Principles

Ideal weight calculators use several classic formulas, such as the Devine equation:

Male: IBW (kg) = 50.0 + 2.3 * (Height_inches - 60) | Female: IBW (kg) = 45.5 + 2.3 * (Height_inches - 60)

How to Calculate (Step-by-Step)

To determine your ideal body weight:

  1. Identify your height in inches. If you are under 5 feet tall, adjustments are made.
  2. Select the formula (Devine, Robinson, Miller, or Hamwi) to calculate your target weight.
  3. Adjust the target by 10% up or down based on your body frame size (small, medium, large).

Practical Examples & Scenarios

Male Ideal Weight Projections (Devine Formula)

Estimating the ideal weight for a 5'10" (70 inches) man.

Inputs Used
Height:5'10" (70 inches)
Gender:Male
Formula Calculation:50.0 + 2.3 * (70 - 60)
Projected Outcomes
Ideal Weight (Devine):73 kg (161 lbs)
Healthy BMI Range Equivalent:129 - 174 lbs

The Devine formula calculates a target weight of 73 kg (161 lbs). This sits comfortably within the healthy BMI weight range.

Ideal Weight Targets (Devine Formula)

HeightMale Ideal Weight (lbs)Female Ideal Weight (lbs)Healthy BMI Range (lbs)
5'4" (1.63 m)135 lbs125 lbs108 - 145 lbs
5'6" (1.68 m)145 lbs135 lbs115 - 154 lbs
5'8" (1.73 m)155 lbs145 lbs122 - 164 lbs
5'10" (1.78 m)165 lbs155 lbs129 - 174 lbs
6'0" (1.83 m)175 lbs165 lbs136 - 184 lbs

Common Pitfalls & Mistakes

  • Treating the calculated ideal weight as a rigid limit, rather than a general healthy range.
  • Ignoring muscle density and body frame structure in calculations.

Frequently Asked Questions

What is the Hamwi formula?

An alternative equation: Male = 106 lbs for first 5 feet + 6 lbs per inch; Female = 100 lbs for first 5 feet + 5 lbs per inch.

How does frame size affect ideal weight?

Small frames lower the ideal weight target by 10%, while large frames increase it by 10%.

Conclusion

Use these formulas to establish a general healthy weight target, adapting it to your individual body structure.

Ready to calculate your own numbers?

Launch the interactive tool corresponding to this article to execute custom calculations.

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