Ideal Body Weight Calculator

1. 1Enter height (in).
2. 2Enter sex.
3. 3Enter actual weight (optional, for comparison) (kg).
4. 4Read your ideal body weight on the right — it updates as you type.
5. 5Hit Share to keep the scenario or send it to someone.

About this calculator

Ideal body weight (IBW) via the Devine formula is the reference weight clinicians use for weight-based drug dosing and mechanical ventilation tidal volume settings, because dosing many medications on actual body weight in an overweight or obese patient can meaningfully overdose the patient — lean tissue, not fat, drives distribution and clearance for many drugs. The Devine formula assigns a base weight for 5 feet of height and adds a fixed increment per inch over that, separately for men and women, reflecting average frame differences. It performs poorly for patients under 5 feet tall (may return negative or unrealistically low numbers) and does not account for large frame variation, so it is a dosing convention rather than a body-composition assessment. Ventilator tidal volume, for example, is set at roughly 6-8 mL per kg of IBW, not actual weight, because lung size tracks height and sex, not body fat. Many drug protocols specify whether to use IBW, adjusted body weight, or actual weight — check the specific drug reference. This tool is for education and workflow support only — not medical advice. Always verify results with a clinician and use clinical judgment alongside your institution's protocols.

What each field means

FAQ

Accuracy and limitations

• Population formulas describe averages; individual bodies vary, especially at the extremes of height, age, or muscle mass.
• Results do not account for medical conditions, medication, or pregnancy.
• Use this as a directional reference, not a diagnosis — talk to a clinician before acting on it.