Calculated
Ideal Weight Calculator
Sign up to favourite this calculatorCompare seven height-based reference formulas, including Peterson, Devine, Robinson and Miller. The results are formula estimates, not a single medically correct or personally ideal body weight.
Formula comparison range
Arithmetic average of formula estimates
66.1 kg| Formula | Estimated reference weight |
|---|---|
| Peterson (2016) | 63.8 kg |
| Miller (1983) | 66.0 kg |
| Robinson (1983) | 65.2 kg |
| Devine (1974) | 65.9 kg |
| Hamwi (1964) | 66.7 kg |
| Broca (1871) | 70.0 kg |
| Lorentz (1929) | 65.0 kg |
Reference estimate only. These height-based formulas do not determine a person's healthy, ideal or medically appropriate weight. They do not account for body composition, muscle mass, age, ethnicity, pregnancy, health conditions or personal goals.
For general information only. This calculator does not diagnose a health condition or replace advice from a qualified healthcare professional. The height-based adult formulas are not designed for children or teenagers — for a child or young person's growth or weight concerns, speak with a GP, school nurse or another qualified health professional.
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Assumptions and limits
- An estimate from the numbers you entered, for guidance only. It is not financial, tax or medical advice.
- Calculator version 1, last updated 25 October 2026.
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How to use this calculator
- Choose the sex to use for the calculation — most of the formulas use different constants for men and women.
- Enter your height, and pick its unit — centimetres, metres, feet, inches, or feet and inches.
- Pick the unit the estimates are shown in — kilograms, pounds, or stones and pounds.
- Read the comparison range across all seven formulas, the arithmetic average beside it, and each individual formula's estimate in the table below.
Nothing is submitted anywhere. The calculation runs in the page as you type, and the link in your address bar carries your figures, so it can be shared or bookmarked.
What do I need to enter?
- Sex — Male or Female. Most of the formulas use different constants for each.
- Height — from 130 cm to 220 cm, or the equivalent in metres, feet, inches or feet and inches (the inches box takes 0 to 11). It is the only measurement the formulas use.
- Show estimates in — Kilograms, Pounds or Stones & pounds. This changes how the results are displayed, not their value.
What do the results show?
- Formula comparison range — the main figure: the lowest to the highest of the seven formula estimates.
- Arithmetic average of formula estimates — the mean of all seven. It is a summary of the figures, not a target.
- Reference weight by formula — a table with each formula's own estimate for your sex and height.
How the comparison works
Different ideal-body-weight formulas can produce different results for the same height. This calculator shows the individual estimates rather than treating one formula as definitive. The range and average summarise the methods shown; neither is a medical recommendation or a personal target.
- Each estimate is calculated independently using one of seven height-based formulas.
- The displayed range is the lowest to the highest of the seven estimates: min(F₁, …, F₇) to max(F₁, …, F₇).
- The displayed average is the arithmetic average of those seven estimates — (F₁ + F₂ + F₃ + F₄ + F₅ + F₆ + F₇) ÷ 7 — not a clinical recommendation.
- Formula estimates differ because the equations were developed from different populations, assumptions and historical datasets.
- Body composition and personal circumstances — muscle mass, frame size, age, ethnicity, health conditions — are not captured by any height-only method.
All seven formulas are defined for every height this calculator accepts (130–220 cm), so the average is always taken over seven values. Estimates are calculated internally in kilograms and then converted to the unit you choose; the range, the average and each row are rounded for display using the site's normal weight-rounding (one decimal place for kilograms, whole pounds, whole stones and pounds).
What are the seven formulas?
Hamwi, Devine, Robinson and Miller share the same shape: a base weight at exactly 5 feet (60 inches) tall, plus a fixed amount of weight for every inch above that.
Estimate (kg) = Base weight + Per-inch amount × (Height in inches − 60)
- Base weight and per-inch amount — the constants in the table below, by sex.
- Height in inches − 60 — how many inches taller than 5 ft the height is.
Peterson works differently: it targets a fixed BMI of 22 regardless of sex. Broca is height alone with no correction — this is the original 1871 version; some later adaptations reduce the female figure by 10%, which this calculator does not apply. Lorentz applies a small sex-specific correction to Broca's figure once height passes 150 cm.
Peterson (kg) = 2.2 × 22 + 3.5 × 22 × (Height in metres − 1.5)
Broca (kg) = Height in centimetres − 100
Lorentz (kg) = Broca's figure − (Height in cm − 150) ÷ divisor
- Lorentz divisor — 4 for men, 2 for women, and 0 correction at or below 150 cm.
| Formula | Published | Men | Women |
|---|---|---|---|
| Peterson | 2016 | Same for both sexes | Same for both sexes |
| Miller | 1983 | 56.2 + 1.41 kg per inch | 53.1 + 1.36 kg per inch |
| Robinson | 1983 | 52 + 1.9 kg per inch | 49 + 1.7 kg per inch |
| Devine | 1974 | 50 + 2.3 kg per inch | 45.5 + 2.3 kg per inch |
| Hamwi | 1964 | 48 + 2.7 kg per inch | 45.5 + 2.2 kg per inch |
| Broca | 1871 | Same for both sexes | Same for both sexes |
| Lorentz | 1929 | Correction ÷ 4 above 150 cm | Correction ÷ 2 above 150 cm |
Worked example. A man 175 cm tall (68.9 inches, 8.9 inches over 5 ft) gets Peterson 67.7 kg, Miller 68.7 kg, Robinson 68.9 kg, Devine 70.5 kg, Hamwi 72.0 kg, Broca 75.0 kg and Lorentz 68.8 kg — a comparison range of 67.7–75.0 kg and an arithmetic average of 70.2 kg.
Limitations of formula-based ideal weight
- Uses only height and sex — it does not account for muscle mass, frame size or age.
- Designed for adults aged 18 and over. None of the seven formulas were derived from children's or teenagers' growth data, and none apply during pregnancy.
- Built for clinical and historical reference use, such as drug dosing, rather than as a fitness or health target.
- It is not a diagnosis, a body-composition assessment or medical advice, and no figure it produces is a safe, optimal, recommended or target weight.
For a range-based view of a healthy weight at your height, use the BMI calculator. For an estimate that accounts for body composition rather than height alone, use the body fat percentage calculator.
Frequently asked questions
What does this ideal weight calculator show?
It runs your height and sex through seven height-based reference formulas — Peterson, Miller, Robinson, Devine, Hamwi, Broca and Lorentz — and shows each estimate individually, the range from lowest to highest, and the arithmetic average of the seven. It is a comparison of formulas, not a single medically correct or personally ideal body weight.
Why do the formulas give different answers?
Each formula was fitted to a different reference population, sometimes decades apart, using different assumptions and historical datasets. Devine (1974) is the version most used in medicine today; Miller and Robinson (both 1983) tend to sit close to it; Broca (1871) and Lorentz (1929) predate BMI-based methods entirely and usually sit furthest from the rest. None is definitively correct, which is why this tool shows all seven rather than picking one.
Is the average my ideal or healthy weight?
No. The figure labelled "arithmetic average of formula estimates" is exactly that — the mean of the seven numbers shown, with no clinical meaning. It is not a recommended, healthy, target, correct or ideal weight. No single formula, and no average of them, tells any individual what they should weigh.
Does the calculator account for muscle mass or body composition?
No. Every formula here uses only height and sex. A muscular or large-framed person will show as heavier than these estimates without that meaning anything is wrong, and body fat, bone structure, age and ethnicity are not inputs. For a measurement that reflects body composition, use the body fat percentage calculator instead.
Is the calculator suitable for children or during pregnancy?
No. All seven formulas were derived from adult populations and assume adult height-to-weight proportions, so they do not apply to children, teenagers or pregnancy. A child or young person’s growth should be assessed against paediatric growth charts by a GP, health visitor or school nurse. Weight during pregnancy should be discussed with a midwife or GP.
How is this different from the BMI calculator?
BMI compares an actual weight and height against a healthy range that applies at any height. This calculator instead predicts a reference weight from height alone, using formulas designed for clinical dosing and historical reference. They answer different questions — see the BMI calculator for the range-based view.
Which formula is the most accurate?
The question does not really have an answer. Each formula is a rough, height-only estimate built for a consistent reference figure, not a precise or personalised target. Devine is the most widely used in clinical practice, and Peterson (2016) is the newest and is built from a target BMI rather than a historical population, but none of them captures frame size, muscle mass, age or overall health.
Last updated 25 October 2026.