OneFreePlace · Tool #139

Replace “one ideal number” with a transparent reference set.

Compare Devine, Robinson, Miller and Hamwi side by side, place them against the adult BMI 18.5–24.9 reference band, inspect the formula spread, choose a BMI target, and optionally see how your current weight relates—without pretending any one equation defines a personally perfect weight.

✓ 4 classic IBW formulas✓ Adult BMI reference band ✓ Target-BMI lab✓ Formula spread + sensitivity ✓ No fake frame-size precision

Ideal Weight Calculator

Devine · Robinson · Miller · Hamwi · BMI band · target-BMI lab

Height-based reference

Enter height and the historical formula reference sex.

Formula reference sex

Height

Unit

Optional current-weight contextUsed only for current BMI and reference comparison.

Current weight

Weight unit

BMI target labChoose a reference BMI inside the adult healthy-weight band.

Target BMI

Primary result unit

The classic formulas are linear around 5 ft (60 in). Below 5 ft, this tool labels their output as an extrapolation rather than presenting it as equally established.

Formula reference set

Calculating

—

classic-formula range

Enter a valid adult height.

Formula median—middle of the four classic estimates

Formula mean—simple arithmetic average

Adult BMI 18.5–24.9—height-based screening reference

Weight at target BMI—exact BMI equation

Formula spread—highest minus lowest classic estimate

Height—converted input

Reference-only resultOptional current weight adds BMI context without changing the classic equations.

Four classic formulas compared

The formulas share the same structure but use different base weights and per-inch slopes, which is why they disagree more at height extremes.

Formula	Reference weight	BMI at that weight	vs median	Equation

BMI-aligned target lab

Exact BMI weight is compared with the 2016 Peterson linear approximation, which was designed to align target-body-weight equations with BMI across height.

Height sensitivity

See how the classic formula median and BMI 18.5–24.9 reference band move around your height. This makes the formulas’ linear slopes visible.

Height	Formula median	Formula range	BMI 18.5–24.9

Current-weight context

Optional only. BMI is a screening measure, not a diagnosis, and it does not distinguish fat mass from lean mass.

Formula audit

All four classic equations use kilograms and total height in inches. Δin = height − 60 in.

Why there is no frame-size multiplier

Not part of the four equationsDevine, Robinson, Miller and Hamwi do not contain a wrist-size or frame-size variable.

Transparent

Avoids false precisionAdding an arbitrary ±10% “frame adjustment” can make a historical formula look more personalized than the evidence supports.

Deliberate

BMI shown separatelyThe wider BMI band provides context without pretending it is the same concept as ideal body weight.

Separate lens

For adults only, and still only a reference.CDC classifies adult BMI 18.5 to under 25 as the healthy-weight category, while also emphasizing that BMI is a screening measure and should be interpreted with other health factors. Children, teens and pregnancy require different approaches.