Free tool · Health
Ideal Weight Calculator
Four classic ideal-weight formulas and the healthy BMI range for your height — both views on one page.
Ideal weight for a man, 178 cm tall?
The four formulas span 70.4 to 75.2 kg; the healthy range for this height is 58.6 to 78.9 kg.
- Height over 5 ft: 178 cm = 70.1 in, so 10.1 in over.
- Devine: 50 + 2.3 × 10.1 = 73.2 kg.
How to use this ideal weight calculator
- Choose Metric (centimetres and kilograms) or Imperial (feet, inches and pounds).
- Pick your sex and enter your height. Optionally add your current weight to see where it sits against the range.
- Use the View pills to switch between the ideal-weight formulas and the healthy BMI range.
- Read the band, not a single gram: the four formulas and the range together describe a sensible zone for your height.
What ideal weight means
"Ideal weight" formulas are height-based rules of thumb from the 1970s and 80s. The best known, Devine (1974), was created to dose medication safely, not to judge bodies — but its numbers landed close to what clinicians considered a sound weight for a height, so it and its rivals (Robinson, Miller, Hamwi) became the standard quick reference.
Alongside them sits the healthy range: the weights that give a BMI between 18.5 and 24.9 at your height. It is wider than any formula's single figure, and for most people it is the more useful target — the formulas tell you the centre of the zone, the range tells you its edges.
The formulas
Devine (1974)
Men: 50 kg + 2.3 kg per inch over 5 ft · Women: 45.5 kg + 2.3
The most widely used of the four — the headline figure on this page, and the one most other calculators show.
Robinson, Miller and Hamwi
Robinson: 52 / 49 kg + 1.9 / 1.7 per inch · Miller: 56.2 / 53.1 + 1.41 / 1.36 · Hamwi: 48 / 45.5 + 2.7 / 2.2
Three refinements from the 1980s. Robinson and Miller usually read lowest, Hamwi highest — together they mark the band.
Healthy range (BMI)
18.5 × height² to 24.9 × height² (height in metres)
The WHO healthy BMI band converted into kilograms for your height. Not a formula for an ideal — a range for a population.
Examples
| Person | Devine | Robinson | Hamwi | Healthy range |
|---|---|---|---|---|
| Man, 178 cm | 73.2 kg | 71.1 kg | 75.2 kg | 58.6 – 78.9 kg |
| Woman, 165 cm | 56.9 kg | 57.4 kg | 56.4 kg | 50.4 – 67.8 kg |
| Man, 185 cm | 79.5 kg | 76.4 kg | 82.7 kg | 63.3 – 85.2 kg |
Four ideal-weight mistakes
Treating it as an exact target
The formulas disagree with each other by several kilograms. Aiming for one decimal-perfect figure mistakes a rule of thumb for a measurement.
Ignoring build and muscle
Frame size and lean mass move a healthy weight a long way. A muscular person above the "ideal" can be leaner than a lighter person inside it.
Chasing the low end
The bottom of the healthy range is an edge, not a goal. For most adults the middle of the range is the sustainable, healthy place to be.
Using it for teenagers
These are adult formulas. Growing bodies are assessed with BMI-for-age percentiles — a completely different yardstick.
Frequently asked questions
Which ideal weight formula is best?
None is a medical truth — all four are height-based rules of thumb. Devine is the most widely used (it was created for medication dosing), Robinson and Miller tend to read lower, Hamwi higher. Read them as a band of roughly ±5 kg, not four competing verdicts.
Why is there also a healthy range?
The healthy range comes from BMI 18.5–24.9 at your height, and it is wider and more forgiving than any single ideal figure. If your weight sits inside the range, the exact ideal number matters much less.
What if I am muscular?
Every formula here, and BMI itself, assumes an average build. Muscular people regularly land above the ideal figures at low body fat. Read the result alongside your body fat percentage and waist, not on its own.
Does ideal weight change with age?
The classic formulas ignore age entirely — they were built from height and sex alone. In practice, a slightly higher weight is common and usually harmless with age; the healthy range is the better guide after about 60.
Is ideal weight the same for men and women?
No. Every formula starts women about 4–5 kg lower at the same height and adds a little less per inch, reflecting average differences in frame and lean mass.
Should children use this calculator?
No. These formulas and the BMI range are for adults only. Children and teenagers are assessed with BMI-for-age percentiles, which account for growth — a different method entirely.
Privacy and important information
This calculator runs entirely in your browser: your numbers are never sent to a server, stored, or shared. Ideal-weight formulas are historical rules of thumb for adults, not medical advice — for a target that fits your body and health, talk to a clinician.
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