Ideal Weight Calculator: Devine, Robinson, Miller, Hamwi and a Healthy BMI Range
Enter your sex and height to see what four classic ideal body weight formulas predict, alongside a healthy weight range built on the lower BMI cut-offs used for Asian Indians.
Your results
Estimates for healthy adults, for education only. Not a medical assessment. Built and reviewed by Umair Hazrami.
How this calculator works
You give it two things: sex and height. It returns five numbers.
1. Healthy BMI range (the main result). Your height in metres is squared, then multiplied by 18.5 and by 22.9. That gives the weight range where your BMI sits in the normal band used for Asian Indians. We use 22.9 as the top, not the international 24.9, because a WHO expert consultation found that a substantial share of Asian people carry high risk of type 2 diabetes and heart disease at BMIs below 25 (WHO Expert Consultation, 2004). An Indian consensus group later set narrower, lower limits of normal BMI for Asian Indians based on body fat and disease data (Misra et al., 2009).
2. Four classic formulas. Each starts with a base weight at 5 feet (152.4 cm) and adds a fixed amount for every inch above that:
| Formula | Men | Women |
|---|---|---|
| Devine (1974) | 50 kg + 2.3 kg/inch | 45.5 kg + 2.3 kg/inch |
| Robinson (1983) | 52 kg + 1.9 kg/inch | 49 kg + 1.7 kg/inch |
| Miller (1983) | 56.2 kg + 1.41 kg/inch | 53.1 kg + 1.36 kg/inch |
| Hamwi (1964) | 48 kg + 2.7 kg/inch | 45.5 kg + 2.2 kg/inch |
Robinson’s paper reports slightly more precise constants (51.65 + 1.85 for men, 48.67 + 1.65 for women), so the rounded version we use, which is the one most references quote, usually reads within about 1 kg of the original (slightly higher) (Robinson et al., 1983). Below 5 feet the calculator returns each formula’s base weight rather than subtracting.
A worked example: a 172 cm man gets a BMI range of 54.7-67.7 kg, and the formulas land between 66.7 kg (Robinson) and 68.8 kg (Hamwi).
How to read your result
Notice how tightly the four formulas cluster. That is not proof they are right. A historical review traced them back to old insurance height-weight tables that broadly agreed with one another, which explains why the formulas agree too (Pai and Paloucek, 2000). Agreement is not accuracy.
Use the BMI range as the wide, sensible zone. Use the formulas as a rough sanity check. Then stop staring at the scale.
For most people who train, the better questions are: how much of my weight is fat, and where is it stored? Measure your waist and run the waist-to-height ratio calculator, or estimate body fat with the body fat calculator. The guide to body fat measurement methods explains how much to trust each number.
If you are above the range and want to change it, set a target with the calorie calculator and track progress with weekly averages, waist and photos, as laid out in this physique tracking guide.
Limitations and who this is not for
- Lifters. Muscle is heavy. A trained person can sit above every formula while lean, so the FFMI calculator or a body fat estimate tells you far more.
- Frame size. Robinson’s own paper derived separate equations by frame size, which these single-line formulas ignore.
- Very short or very tall adults. The per-inch slopes were fitted to average heights and get less believable at the extremes.
- Under-18s, pregnancy, older adults and anyone with a medical condition. These formulas were not designed for you. Children need growth charts, and older adults or anyone with a health condition should get a target from their doctor.
If you are losing weight without trying, have a history of disordered eating, or are well outside the range with raised blood pressure or blood sugar, talk to a doctor or registered dietitian rather than chasing a formula.
Frequently Asked Questions
Which ideal weight formula is the most accurate?
None of them is accurate for an individual, because all four were built from population height-weight data rather than body composition. A historical review found they give similar answers because they come from similar height-weight tables, and concluded any one of them can be used. Treat the spread between them as a rough zone, not a target.
Why do the four formulas give different numbers?
Each one uses a slightly different starting weight at 5 feet and a different amount added per inch above that. At average heights the gap is roughly 2 kg for men and can reach 4 to 5 kg for women, and it widens further at the very short and very tall ends. That spread is a useful reminder of how imprecise the idea of one 'ideal' number is.
Why is the main result a range and not a single weight?
The headline number is the weight that puts you at a BMI of 18.5-22.9, the normal band used for Asian Indians. A range is more honest than one figure, because healthy people of the same height carry very different amounts of muscle and bone. If you sit anywhere inside it with a waist under half your height, you are in a sensible place.
I lift weights and I'm above my ideal weight. Is that a problem?
Not necessarily, because these formulas cannot tell muscle from fat. A lifter with a lot of muscle can sit well above every formula and still be lean. Check your waist-to-height ratio or estimate body fat instead of chasing the scale number.
Are these formulas meant for fitness goals?
Not originally. The Devine and Robinson equations became popular in hospital pharmacy for estimating drug doses, and Robinson's paper was explicitly about dosage calculations. They are a quick reference point for the general public, not a physique goal.
Does the calculator work if I am under 5 feet tall?
Only roughly. The formulas add weight for each inch above 5 feet, so below 5 feet this calculator stops subtracting and simply returns each formula's 5-foot base weight. For shorter adults the BMI range is the more sensible number to look at.
When should I see a doctor about my weight?
See a doctor if you are losing weight without trying, if your BMI is below 18.5, or if you have symptoms such as fatigue, missed periods or dizziness. The same applies if you are well above the range and have high blood pressure, high sugar readings or a family history of diabetes. A calculator can flag a number, but it cannot diagnose anything.
Sources & References
Every claim above is checked against peer-reviewed research (PubMed, U.S. National Library of Medicine) or guidance from established health bodies. How we fact-check.
- Pai MP, Paloucek FP. The origin of the ideal body weight equations. Ann Pharmacother. 2000. PMID: 10981254
- Robinson JD, et al. Determination of ideal body weight for drug dosage calculations. Am J Hosp Pharm. 1983. PMID: 6869387
- WHO Expert Consultation. Appropriate body-mass index for Asian populations and its implications for policy and intervention strategies. Lancet. 2004. PMID: 14726171
- Misra A, et al. Consensus statement for diagnosis of obesity, abdominal obesity and the metabolic syndrome for Asian Indians and recommendations for physical activity, medical and surgical management. J Assoc Physicians India. 2009. PMID: 19582986