# IBW & ABW calculator

## Estimated Ideal Body Weight (IBW) Formula

• Male: 50 kilogram (kg) + 2.3 kg for each inch over 5 feet.
• Female: 45.5 kg + 2.3 kg for each inch over 5 feet.

This formula only applies to persons 60 inches (152 cm) or taller.

## Estimated Adjusted Body Weight (ABW) Formula

0.4 × (actual weight - IBW) + IBW

## Examples

1. Calculate the IBW of a man who is 81 ½" (inches) tall and weighs 209 pounds (lb). If this man is obese (> IBW + 30%), calculate the ABW.

• Male IBW = 45.5 kg + 2.3 × each inch over 60"
• 209 lb ÷ 2.2 = 95 kg
• 81.5" - 60" = 21.5"
• 50 kg + 21.5 x 2.3"
• IBW = 99.45 kg

The man's actual weight is less than IBW + 30% so it is not necessary to calculate the ABW.

2. Calculate the IBW of a man who is 64" tall and weighs 70 kg. If this man is obese (> IBW + 30%), calculate the ABW.

• Male IBW = 45.5 kg + 2.3 × each inch over 60"
• 64" - 60" = 4"
• 50 kg + 2.3 x 4"
• IBW = 59.2 kg

The man's actual weight is less than IBW + 30% so it is not necessary to calculate the ABW.

3. Calculate the ideal body weight (IBW) of a woman who is 64" tall and weighs 80 kg. If this woman is obese (> IBW + 30%), calculate the ABW.

• Female IBW = 45.5 kg + 2.3 × each inch over 60"
• 64" - 60" = 4"
• 45.5 kg + 2.3 x 4"
• IBW = 54.7 kg

The woman's actual weight is greater than the IBW + 30%, so calculate the ABW

• ABW = 0.4 × (actual weight - IBW) + IBW
• 0.4 ×( 80kg - 54.7 kg) + 54.7 kg
• ABW = 64.82 kg
Formulas referenced from GlobalRPH.

## References

• Beyer, W. H. (2018). Handbook of mathematical science. CRC press.