Ideal Body Weight (IBW) Calculator

Ideal body weight (IBW) formulas estimate a weight associated with typical dosing or frame sizes at a given height. They were designed for adults and differ slightly by the population data they used. This calculator shows four well-known methods side by side—Devine, Hamwi, Robinson, and Miller—so you can see the range rather than a single number.

The average IBW (across formulas) gives a practical midpoint. We also compute a healthy weight range based on BMI 18.5–24.9 and estimate lean body mass (LBM) from the Boer equation using the average IBW as weight input. Use these values as orientation points, not prescriptions.

How to measure height accurately

• Stand barefoot, heels and back lightly against a wall; head neutral, eyes forward.
• Use a flat object on the crown and mark the wall; measure to the floor.
• Record to the nearest centimeter or quarter inch; if possible average two readings.

IBW vs. BMI vs. LBM

IBW is a height-based target used in clinical contexts (e.g., drug dosing) and general guidance. It does not account for muscle mass, bone density, or fat distribution. Different formulas yield slightly different figures because they were derived from different reference groups.

BMI reflects mass relative to height and helps define broad “healthy weight” bands. However, a muscular person may exceed “normal” BMI despite low body fat.

LBM approximates the non-fat component (bone, organs, muscle). Our Boer estimate uses your average IBW as weight input to give you a ballpark body-composition anchor. Treat it as illustrative rather than diagnostic.

Practical tips

Think of IBW as a navigation aid, not a destination. If your current weight is above the IBW range, small, sustainable changes—like a 10–15 minute daily walk, prioritizing protein at meals, and sleeping 7–9 hours—tend to work better than dramatic overhauls. Pair targets with performance markers (strength, pace) so progress isn’t judged by scale weight alone. Hydration, sodium, and menstrual cycle can shift day-to-day readings; look at trends over weeks, not single points. Health conditions and medications matter; combine IBW with professional advice.

Which IBW formula is “best”?

No single method is universally superior. Devine is common in medicine, Hamwi is popular in dietetics, and Robinson/Miller provide alternative calibrations. Viewing them together avoids tunnel vision.

Does frame size or age matter?

Classic IBW equations don’t include frame size or age. Consider the BMI range and your personal context (build, training, health goals).

Can I use IBW for goal setting?

Yes, as a starting reference—combine it with waist measures (e.g., waist-to-height ratio) and your physician’s advice.

Is IBW for children or teens?

No—these formulas target adults. Use pediatric growth charts for younger ages.