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Ideal Weight Calculator — Lorentz & Devine Formulas

Find your ideal body weight by height with the Lorentz (1929) and Devine (1974) clinical formulas. Enter height and sex — get both numbers, a height-by-height table, and your healthy BMI range.

🗓️ Updated June 2026 Reviewed by Martín Rodríguez

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Reviewed by: Martín Rodríguez (editorial policy ) · Last reviewed: Jun 20, 2026

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Ideal Weight Calculator by Height and SexCalculate your ideal weight using Devine, Robinson, and Lorentz formulas. WHO healthy BMI range. Men and women.Ideal Weight for Women by Height (Devine, Robinson & Hamwi)Find your ideal weight for women by height using three evidence-based formulas (Devine, Robinson, Hamwi). Includes a reference chart from 5'0" to 6'0" and frame size adjustments.How Tall Will My Child Be? Adult Height PredictorPredict your child's adult height from the parents' heights with the Tanner mid-parental formula. Free calculator + height chart by parents and a ±8.5 cm range.How Much Should a Child Weigh? Healthy Weight by Age & SexHow much should your child weigh? Enter age and sex to get the healthy weight range (15th–85th percentile) from official WHO growth standards, plus a full weight-by-age chart for boys and girls.

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The Devine (1974) and Lorentz (1929) formulas are the two most cited clinical references for estimating ideal body weight (IBW) in adults. The Devine formula is the US hospital standard for dosing hydrophilic drugs (aminoglycosides, heparins) and setting tidal volumes in mechanical ventilation (ARDS Network protocol). Lorentz is widely used in Europe as a general population reference. This calculator applies both formulas simultaneously and cross-checks the result against the WHO healthy BMI range (18.5–24.9).

When to use this calculator

Clinicians and pharmacists calculating drug doses for hydrophilic medications (Devine is the standard for aminoglycosides such as gentamicin and tobramycin).
ICU teams setting protective tidal volumes in mechanical ventilation (ARDS Network: 6 mL/kg of Devine ideal body weight).
Dietitians and nutritionists using IBW as a starting reference for body composition goals.
Patients who want a quick clinical reference number before a medical or nutritional consultation.

Ideal Body Weight by Height — Lorentz & Devine Formulas (kg)

Height	Lorentz Male	Devine Male	Lorentz Female	Devine Female	Healthy BMI Range (18.5–24.9)
150 cm (4'11")	50.0	50.0	50.0	45.5	41.6–56.0 kg
155 cm (5'1")	53.8	52.4	52.5	47.9	44.4–59.8 kg
160 cm (5'3")	57.5	56.9	55.0	52.4	47.4–63.7 kg
165 cm (5'5")	61.3	61.4	57.5	56.9	50.4–67.8 kg
170 cm (5'7")	65.0	65.9	60.0	61.4	53.5–72.0 kg
175 cm (5'9")	68.8	70.5	62.5	66.0	56.7–76.3 kg
178 cm (5'10")	71.0	73.2	64.0	68.7	58.6–78.9 kg
180 cm (5'11")	72.5	75.0	65.0	70.5	59.9–80.7 kg
185 cm (6'1")	76.3	79.5	67.5	75.0	63.3–85.2 kg
190 cm (6'3")	80.0	84.0	70.0	79.5	66.8–89.9 kg

Fuente: Devine BJ, Drug Intelligence and Clinical Pharmacy (1974); Lorentz formula (1929); WHO BMI classification for adults. Below 5 ft (152.4 cm), Devine returns the base weight (50 kg male / 45.5 kg female) with no inches-over-5-ft adjustment. To convert kg to lb, multiply by 2.205.

How it works

How It's Calculated

Lorentz formula (1929) — uses height and sex:

Male:   IBW = height(cm) − 100 − (height − 150) / 4
Female: IBW = height(cm) − 100 − (height − 150) / 2

Devine formula (1974) — based on inches over 5 feet (152.4 cm):

Male:   IBW = 50 kg   + 2.3 kg × inches_over_5ft
Female: IBW = 45.5 kg + 2.3 kg × inches_over_5ft

where: inches_over_5ft = max(0, (height_cm − 152.4) / 2.54)

Worked example — male, 178 cm (5'10"):

Lorentz: 178 − 100 − (178 − 150) / 4 = 78 − 7 = 71.0 kg

Devine: (178 − 152.4) / 2.54 ≈ 10.08 in → 50 + 2.3 × 10.08 ≈ 73.2 kg

Ideal Weight by Height (kg)

Reference table of ideal body weight by height and sex, using both formulas. The last column is the WHO healthy BMI range (18.5–24.9) — the spread most adults should aim within rather than a single number.

Height	Lorentz (M)	Devine (M)	Lorentz (F)	Devine (F)	Healthy BMI range
150 cm (4'11")	50.0	50.0	50.0	45.5	41.6 – 56.0
155 cm (5'1")	53.8	52.4	52.5	47.9	44.4 – 59.8
160 cm (5'3")	57.5	56.9	55.0	52.4	47.4 – 63.7
165 cm (5'5")	61.3	61.4	57.5	56.9	50.4 – 67.8
170 cm (5'7")	65.0	65.9	60.0	61.4	53.5 – 72.0
175 cm (5'9")	68.8	70.5	62.5	66.0	56.7 – 76.3
178 cm (5'10")	71.0	73.2	64.0	68.7	58.6 – 78.9
180 cm (5'11")	72.5	75.0	65.0	70.5	59.9 – 80.7
185 cm (6'1")	76.3	79.5	67.5	75.0	63.3 – 85.2
190 cm (6'3")	80.0	84.0	70.0	79.5	66.8 – 89.9

To convert to pounds, multiply kg by 2.205. Below 5 ft (152.4 cm) the Devine formula has no inches-over-5-ft adjustment, so it returns the base weight (50 kg male / 45.5 kg female).

Clinical Context

The Devine formula was published in 1974 in Drug Intelligence and Clinical Pharmacy to provide a standardized weight reference for gentamicin dosing. Because gentamicin (and other hydrophilic drugs) does not distribute well into adipose tissue, using actual body weight in obese patients leads to toxicity. Devine's IBW gave a practical ceiling. It later became the basis for the ARDS Network mechanical ventilation protocol: tidal volumes of 6 mL/kg of predicted body weight (PBW, which is the Devine IBW).

Comparison of Common IBW Formulas

Formula	Year	Variables	Main use
Broca	1871	Height	Simple estimate (height cm − 100)
Lorentz	1929	Height, sex	European clinical reference
Hamwi	1964	Height, sex	Diabetes and clinical nutrition
Devine	1974	Height, sex	Drug dosing, ICU ventilation
Robinson	1983	Height, sex	US hospital pharmacokinetics
Miller	1983	Height, sex	US hospital pharmacokinetics

For most adults in the 160–185 cm range, the various formulas agree within ±3–5 kg. The WHO healthy BMI range (18.5–24.9) captures individual variation better than a single ideal number.

Important Limitations

These formulas are not valid for: children and adolescents (use WHO/CDC growth percentile charts); patients with amputations (apply limb-correction factors); pregnant women; athletes with high muscle mass; older adults with significant sarcopenia; or extreme heights (< 130 cm or > 210 cm). For health decisions, complement with BMI, waist circumference, DEXA, and a full nutritional assessment.

Editorial Review

Reviewed by the Hacé Cuentas editorial team. Formulas verified against the original Devine (1974) publication in Drug Intelligence and Clinical Pharmacy, the ARDS Network mechanical ventilation protocol, and ASHP drug-dosing guidelines. The healthy BMI range follows current WHO criteria.

Disclaimer: This calculator is for informational purposes only and does not replace consultation with a licensed healthcare professional. For clinical or medical decisions, always consult your physician, pharmacist, or specialist.

Example: male, 5'10" (178 cm)

Lorentz (male): 178 − 100 − (178 − 150) / 4 = 78 − 7 = 71 kg (156.5 lb)

Devine (male): inches over 5 ft = (178 − 152.4) / 2.54 ≈ 10.1 in → 50 + 2.3 × 10.1 ≈ 73.2 kg (161.4 lb)

WHO healthy BMI range at 178 cm: 58.6 – 78.9 kg (129 – 174 lb)

Both formulas fall well within the healthy BMI range; they differ by only 2.2 kg

Lorentz: 71 kg | Devine: 73.2 kg — both within the WHO healthy range of 58.6–78.9 kg

Frequently asked questions

What is the exact Lorentz formula for ideal weight?

The Lorentz formula (1929) is: IBW = height(cm) − 100 − (height − 150) / 4 for males and IBW = height(cm) − 100 − (height − 150) / 2 for females. Both use only height and sex — not age. For example, a male at 178 cm: 178 − 100 − 28/4 = 71 kg.

What is the Devine formula and why is it used in hospitals?

The Devine formula (1974) calculates IBW as 50 kg + 2.3 kg per inch over 5 ft (males) and 45.5 kg + 2.3 kg per inch over 5 ft (females). It was developed for gentamicin dosing because hydrophilic drugs don't distribute into fat. It's now the US clinical standard for aminoglycoside dosing and for setting protective tidal volumes in mechanical ventilation (ARDS Network protocol).

How different are the Lorentz and Devine results?

For typical adult heights (160–185 cm), the two formulas usually agree within 1–4 kg. At 178 cm male: Lorentz = 71 kg, Devine = 73.2 kg (2.2 kg difference). At 165 cm female: Lorentz ≈ 57.5 kg, Devine ≈ 56.9 kg (0.6 kg difference). Larger differences appear at shorter or taller heights.

Why are the male and female results different at the same height?

Both formulas account for average physiological differences: women have a higher proportion of adipose tissue and lower relative bone and muscle mass than men at the same height. Lorentz uses a smaller divisor for women (2 vs. 4); Devine uses a lower base weight (45.5 vs. 50 kg).

Does the Lorentz formula include age?

No. The standard Lorentz formula (1929) uses only height and sex — not age. Some websites show age-corrected variants, but those are not the validated clinical version. This calculator applies the original Lorentz and Devine formulas as published in the medical literature.

Is the 'ideal weight' the weight I should aim for?

Not necessarily. These formulas give a single clinical reference number derived from actuarial mortality studies from the 1920s–1970s. For personal health goals, the WHO recommends the healthy BMI range (18.5–24.9), which spans 6–7 kg at a given height. Body composition (muscle vs. fat mass) matters more than a single target number.

Can I use these formulas for children or teenagers?

No. Lorentz and Devine are adult-only formulas. For children and adolescents, weight assessment uses WHO and CDC age-and-sex-specific growth percentile charts that account for developmental stage. Consult a pediatrician for anyone under 18.

Do these formulas work at very short or very tall heights?

They're most accurate between approximately 155–195 cm. Below ~150 cm, the Devine formula underestimates because its baseline is 5 ft (152.4 cm). Above ~200 cm, both formulas tend to overestimate because body proportions shift. At extreme heights, the BMI range and professional assessment are more reliable.

What is my ideal weight if I am 170 cm tall?

At 170 cm: a male gets Lorentz 65.0 kg and Devine 65.9 kg; a female gets Lorentz 60.0 kg and Devine 61.4 kg. The WHO healthy BMI range at 170 cm is 53.5–72.0 kg, so any weight inside that band is medically healthy.

How do I convert the ideal weight result to pounds?

Multiply the kilogram result by 2.205. For example, a Devine result of 73.2 kg for a 178 cm male equals about 161.4 lb, and a Lorentz result of 71 kg equals about 156.5 lb.

Sources & references

Methodology & trust

Editorial

Calculadora de salud revisada por el equipo editorial de Hacé Cuentas, contrastada con Devine BJ. Gentamicin therapy. Drug Intelligence and Clinical Pharmacy. 1974;8:650–655., según nuestra política editorial y metodología.

Updates

Última revisión: June 20, 2026. Los parámetros se verifican periódicamente con las fuentes citadas.

Privacy

Calculations run 100% in your browser. We do not store or transmit your data.

Limitations

Indicative results. For critical decisions, consult a professional.

📌 How to cite this calculator

Rodríguez, M. (2026). Ideal Weight Calculator — Lorentz & Devine Formulas. Hacé Cuentas. https://hacecuentas.com/ideal-weight-lorentz-devine-formula

Contenido bajo licencia CC-BY 4.0 — reutilizable citando la fuente con enlace a Hacé Cuentas.

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