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Ideal Weight Calculator

Computes ideal body weight from height and sex with the four common clinical formulas (Devine, Robinson, Miller, Hamwi) and the BMI 18.5–24.9 healthy range.

When to use

You need a reference 'ideal' weight for an adult, e.g. for drug dosing (Devine) or general guidance, or the healthy weight range for a height.

Do not use when: The person is under 18 or you need body-composition targets; the formulas are population averages, not individual prescriptions.

Formula

With h = inches over 5 ft (60 in): Devine male 50 + 2.3h, female 45.5 + 2.3h; Robinson male 52 + 1.9h, female 49 + 1.7h; Miller male 56.2 + 1.41h, female 53.1 + 1.36h; Hamwi male 48 + 2.7h, female 45.5 + 2.2h. For heights under 5 ft the same slope is applied downward.

Inputs

Parameter	Type	Unit	Required	Description
`sex`	enum: male \| female		yes	Biological sex used to select the formula coefficients.
`height_cm`	number	cm	yes	Height in centimetres. Formulas are defined for heights above 152.4 cm (5 ft). Range: ≥ 120, ≤ 260

Outputs

Output	Type	Unit	Description
`devine_kg`	number	kg	Most widely used in pharmacology.
`robinson_kg`	number	kg	Robinson et al. modification.
`miller_kg`	number	kg	Miller et al. modification.
`hamwi_kg`	number	kg	Hamwi method.
`healthy_bmi_range_min_kg`	number	kg	Weight at BMI 18.5.
`healthy_bmi_range_max_kg`	number	kg	Weight at BMI 24.9.

Example

Male, 175 cm: {"sex":"male","height_cm":175} → {"devine_kg":70.5,"robinson_kg":68.9,"miller_kg":68.7,"hamwi_kg":72,"healthy_bmi_range_min_kg":56.7,"healthy_bmi_range_max_kg":76.3}

Female, 160 cm: {"sex":"female","height_cm":160} → {"devine_kg":52.4,"robinson_kg":54.1}

GET https://tttkmbb.com/api/v1/calculate/ideal-weight?sex=male&height_cm=175

Machine access

API: GET https://tttkmbb.com/api/v1/calculate/ideal-weight (query parameters) or POST with a JSON body {"inputs": {...}}
Schema: https://tttkmbb.com/api/v1/calculators/ideal-weight · Markdown: https://tttkmbb.com/health/ideal-weight.md · JSON definition: https://tttkmbb.com/health/ideal-weight.json
MCP: server https://tttkmbb.com/mcp, tool run_calculator with calculator_id="ideal-weight"
OpenAPI operationId: calculate_ideal_weight
Freshness: static. Authentication: none. Rate limit: fair use (see rate limits).

Sources

Pai MP, Paloucek FP (2000) The origin of the 'ideal' body weight equations, Ann Pharmacother 34:1066-1069 (peer_reviewed)
WHO – A healthy lifestyle: body mass index (standard)

FAQ

Why do the formulas disagree?

Each was fitted to a different reference population and purpose (Devine for drug dosing, Hamwi for dietetics). Differences of 2–4 kg are normal; the BMI range is a broader, evidence-based guide.

Is ideal weight the same as healthy weight?

No. 'Ideal' formulas give a single point estimate; a healthy weight is any weight in the BMI 18.5–24.9 range for adults, with body composition taken into account.

Related calculators

BMI Calculator — Check where a current weight falls in the BMI categories.