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Free online ideal body weight calculator

Ideal body weight (IBW) is a height-based estimate of a healthy target weight. This calculator runs four widely cited formulas and shows you where they agree — and where they.

Sex
Units
Average ideal weight
— lb
Typical range
— lb
Low to high across all formulas
Formula breakdown
Devine
— lb
Robinson
— lb
Miller
— lb
Hamwi
— lb
About this calculator

How to use

  1. Select sex and unit system with the toggles.
  2. Enter your height in inches or centimeters.
  3. The average ideal weight and the range across all four formulas appear instantly.
  4. The formula breakdown shows each result individually.

The four formulas

All formulas compute weight from height above 5 feet (60 inches). Heights below 5 ft extrapolate backward from the base values.

Devine (1974):

Men:   50 kg + 2.3 kg per inch over 60 in
Women: 45.5 kg + 2.3 kg per inch over 60 in

Robinson (1983):

Men:   52 kg + 1.9 kg per inch over 60 in
Women: 49 kg + 1.7 kg per inch over 60 in

Miller (1983):

Men:   56.2 kg + 1.41 kg per inch over 60 in
Women: 53.1 kg + 1.36 kg per inch over 60 in

Hamwi (1964) — originally in pounds:

Men:   106 lb + 6 lb per inch over 60 in
Women: 100 lb + 5 lb per inch over 60 in

Worked example

Male, 5 ft 7 in (67 in) — 7 inches above 5 ft:

FormulaCalculationResult
Devine50 + 2.3 × 7 = 66.1 kg145.7 lb
Robinson52 + 1.9 × 7 = 65.3 kg143.9 lb
Miller56.2 + 1.41 × 7 = 66.1 kg145.7 lb
Hamwi106 + 6 × 7148.0 lb

Average ≈ 145.8 lb (66.1 kg). Range: 143.9–148.0 lb.

Notes

Health disclaimer: Ideal body weight formulas are population-level estimates originally designed for clinical drug dosing, not personal fitness targets. They do not account for muscle mass, body composition, or age. Consult a healthcare professional before using IBW to set a weight goal.

  • Sources: Devine BJ (1974) Drug Intelligence and Clinical Pharmacy; Robinson JD et al. (1983) JPEN; Miller DR et al. (1983) Am J Hosp Pharm; Hamwi GJ (1964) Diabetes.

References

Frequently asked

What is ideal body weight and how is it used?
Ideal body weight is a height-based estimate originally developed for clinical drug dosing — medications like gentamicin and vancomycin are dosed on IBW rather than total weight to avoid overdosing obese patients. It is also used as a rough fitness target, though it does not account for muscle mass, age, or body composition.
Why do the four formulas give different numbers?
Each formula was developed independently from different study populations in different decades. Devine (1974) and Robinson (1983) were drug-dosing references; Miller (1983) and Hamwi (1964) came from clinical nutrition. They use slightly different base weights and per-inch increments, so results can differ by 5–15 lb for the same height.
Should I use IBW as my personal weight goal?
Not necessarily. IBW formulas do not account for muscle mass, frame size, age, or body composition. A heavily muscled person may weigh well above IBW with very low body fat. Think of IBW as a clinical reference point, not a personal target. Pair it with BMI and body fat percentage for a fuller picture.
Which formula is the most accurate?
No single formula is definitively best for the general population. Devine is the most widely used in clinical settings. Robinson and Miller tend to give slightly lower values. The average of the four formulas, or the range they span, is often a more useful reference than any single estimate.
Can I share my results with a link?
Yes. Use the "Share with my numbers" button to copy a URL that encodes your height and sex as query parameters. Anyone who opens it will see the same inputs pre-filled.

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