Enter your sex and height into the calculator to estimate an ideal body weight (IBW) reference value according to the Hamwi formula. This calculator is designed to provide an estimate of the ideal body weight for adults.

Ideal Body Weight — Hamwi Formula

Enter your height and sex to estimate ideal body weight. Use the second tab to compare four clinical formulas.
Hamwi IBW
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Supported adult range: 48–84 in (122–213 cm).
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Ideal Body Weight (Hamwi)
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Low (−10%)
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High (+10%)
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BMI at IBW
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Four common IBW formulas for at :
Formulas differ by era and population studied. Treat results as reference estimates, not targets — consult a clinician for personal guidance.
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Note: This calculator provides an educational estimate (Hamwi IBW reference) and isn’t medical advice. Don’t use it as a “goal weight” or to diagnose health status. Not intended for children/teens, pregnancy/postpartum, or people with a history of eating disorders. Don’t use IBW for medication dosing unless a clinician specifically instructs you.

Hamwi Formula

The Hamwi method estimates an adult ideal body weight (IBW) from height using sex-based reference values. It is best used as a quick reference point for comparison, nutrition planning, and general screening. It does not directly measure body fat, muscle mass, or overall health status.

Hamwi ideal body weight formula

Male reference

IBW_{lb} = 106 + 6(H - 60)

Female reference

IBW_{lb} = 100 + 5(H - 60)

Here, H is height in inches. Because the reference point is 60 inches, the formula adds weight above 5 feet and subtracts weight below 5 feet automatically.

Hamwi formula in kilograms

Male reference

IBW_{kg} \approx 48.1 + 2.72(H - 60)

Female reference

IBW_{kg} \approx 45.4 + 2.27(H - 60)

Height conversion formulas

If your height is entered in centimeters or meters, convert it to inches before applying the Hamwi equation.

H_{in} = \frac{H_{cm}}{2.54}
H_{in} = 39.3701 \times H_{m}

How to calculate ideal body weight

  1. Select the sex reference used by the calculator.
  2. Enter height in inches, centimeters, or meters.
  3. Convert height to inches if needed.
  4. Apply the correct Hamwi equation.
  5. Read the result in pounds or kilograms.

IBW range around the estimate

Some calculators also show a comparison band around the Hamwi estimate. A common presentation is 10% below to 10% above the calculated IBW.

IBW_{low} = 0.9 \times IBW
IBW_{high} = 1.1 \times IBW

Hamwi reference table

Height Male IBW Female IBW
5 ft 0 in 106 lb (48.1 kg) 100 lb (45.4 kg)
5 ft 2 in 118 lb (53.5 kg) 110 lb (49.9 kg)
5 ft 4 in 130 lb (59.0 kg) 120 lb (54.4 kg)
5 ft 6 in 142 lb (64.4 kg) 130 lb (59.0 kg)
5 ft 8 in 154 lb (69.9 kg) 140 lb (63.5 kg)
5 ft 10 in 166 lb (75.3 kg) 150 lb (68.0 kg)
6 ft 0 in 178 lb (80.7 kg) 160 lb (72.6 kg)

Example calculations

Male, 70 inches tall

IBW = 106 + 6(70 - 60) = 166 \text{ lb}

Female, 64 inches tall

IBW = 100 + 5(64 - 60) = 120 \text{ lb}

How to interpret your result

  • Use it as a reference, not a diagnosis. A result above or below Hamwi IBW does not by itself determine whether someone is healthy or unhealthy.
  • Body composition matters. Two people can have the same height and weight but very different levels of muscle mass and body fat.
  • Frame size and build can shift practical expectations. A simple Hamwi calculator does not fully account for skeletal frame, athletic build, edema, or unusual body proportions.
  • It is most appropriate for adults. It is not designed for children or teenagers, and it should be interpreted cautiously in pregnancy and other special situations.
  • Clinical context matters. In healthcare settings, IBW may be used alongside other measures rather than by itself.

When the Hamwi formula is useful

  • Getting a fast height-based weight reference
  • Comparing different ideal body weight methods
  • Building a general nutrition or wellness estimate
  • Reviewing an adult height-to-weight benchmark in pounds or kilograms

Hamwi formula FAQ

Is the Hamwi formula the same as BMI?
No. Hamwi gives a reference body weight based on height, while BMI compares a person’s current weight to height. They answer different questions.
What happens if height is below 5 feet?
The same equation still works. Because 60 inches is subtracted inside the formula, heights below 5 feet reduce the final IBW estimate.
Why might my actual healthy weight differ from the Hamwi result?
The formula does not capture body-fat distribution, muscle mass, frame size, training status, age-related changes, or medical conditions that can affect body weight.
Should Hamwi IBW be treated as a target weight?
It is better viewed as a reference value. Personal goals and clinical decisions should consider broader health factors, not only a single formula result.
Can I use Hamwi IBW for medication dosing?
Only if a clinician or protocol specifically tells you to do so. Medication dosing rules depend on the drug and the clinical setting.