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Ideal Weight Calculator

Estimate your ideal body weight using four named formulas (Devine, Robinson, Miller, Hamwi) plus the healthy BMI range — a more specific companion to a plain BMI calculator.

✓ Last reviewed: Sources: Peterson CM, Thomas DM, Blackburn GL, Heymsfield SB (2016) — Universal equation for estimating ideal body weight, Am J Clin Nutr

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Your height, standing

Optional — compares your weight against the healthy BMI range and shows it on the gauge below

Advanced options

Body frame

A subjective estimate, not a measurement — only adjusts the Hamwi formula (±10%)

Pick one formula as the reference — the chips below show how much each of the others differs from it.

Your result

Fill in the fields above to see your result.

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What the ideal weight calculator measures

An ideal weight calculator gives you a specific number of kilograms — not just a wide BMI band, but a narrower target range — worked out from five independent, historical formulas: Devine (1974), Robinson (1983), Miller (1983), Hamwi (1964) and Broca-Brugsch (1871). Each one was built at a different time for a different purpose, so they don’t quite agree for the same height. Rather than pretend one of them is “the” correct number, this calculator shows all five and highlights the range.

That makes it a different tool from our BMI calculator, which gives a wide healthy-weight band (18.5–24.9 BMI per the WHO) based on height alone. Here you get a narrower range built from formulas that factor in sex and, optionally, body frame size. If what you actually want is body composition — how much of your weight is fat versus muscle — see the body fat calculator instead. None of the five formulas here measure muscle or fat directly; they only use sex and height.

Once you enter your sex and height, you get:

  • an ideal weight range from the four main formulas (Devine, Robinson, Miller, Hamwi),
  • the healthy BMI weight range for your height, for comparison,
  • each of the five formulas broken out individually, with one you can highlight (including historical Broca),
  • optionally, how your current weight compares against both ranges and against other people who’ve used the calculator.

How to use the ideal weight calculator

  1. Choose your sex. All five formulas use different constants for men and women — this field is required.
  2. Enter your height (standing). Use the cm/in switch on the field to match your preferred units.
  3. Optional: enter your current weight. The calculator compares it against the healthy BMI range and marks it on the result gauge.
  4. Advanced — body frame size. Small, medium or large. This is a subjective estimate, not a wrist measurement — it only adjusts the Hamwi formula, by ±10%.
  5. Advanced — formula to highlight. Devine is the default, the most commonly cited of the five, but you can switch to Robinson, Miller, Hamwi, or the historical Broca-Brugsch.

How the ideal weight formulas work

Four of the five formulas — Devine, Robinson, Miller and Hamwi — share the same structure: a baseline at 152.4 cm (exactly 60 inches, or 5 feet), plus a fixed amount for every inch above that. The fifth, Broca-Brugsch, works differently, calculating straight from height in centimetres.

Formula Year Men (kg) Women (kg)
Devine 1974 50 + 2.3 × (inches − 60) 45.5 + 2.3 × (inches − 60)
Robinson 1983 52 + 1.9 × (inches − 60) 49 + 1.7 × (inches − 60)
Miller 1983 56.2 + 1.41 × (inches − 60) 53.1 + 1.36 × (inches − 60)
Hamwi 1964 (106 + 6 × (inches − 60)) lb × frame factor (100 + 5 × (inches − 60)) lb × frame factor
Broca-Brugsch 1871 (height cm − 100) × 0.9 (height cm − 100) × 0.85

“Inches” is your height converted from centimetres (height ÷ 2.54). The Hamwi result is worked out in pounds first, then converted to kilograms (1 lb = 0.45359237 kg), and the frame-size multiplier (0.9 for small, 1.0 for medium, 1.1 for large) adjusts only that one formula — none of the others here account for body frame.

The Devine formula was originally published in 1974 for drug dosing in patients whose body weight fell outside typical ranges — not as a tool for finding a “dream weight.” Robinson and Miller are independent 1983 refinements of the same idea, built on broader datasets. Hamwi, from 1964, comes out of dietetic practice. Broca-Brugsch is the oldest of the five, a French formula dating to 1871 — which is why it’s deliberately kept out of the headline range and shown separately, alongside the other four, as a historical reference point.

The ideal weight range you see as the main result is simply the lowest and highest value among Devine, Robinson, Miller and Hamwi — Broca is excluded from it.

Step-by-step example

A man, 170 cm tall, medium frame.

  1. Height in inches: 170 ÷ 2.54 = 66.93. Amount over 60 inches: 66.93 − 60 = 6.93.
  2. Devine: 50 + 2.3 × 6.93 = 65.9 kg.
  3. Robinson: 52 + 1.9 × 6.93 = 65.2 kg.
  4. Miller: 56.2 + 1.41 × 6.93 = 66.0 kg.
  5. Hamwi: (106 + 6 × 6.93) = 147.58 lb × 0.45359237 = 66.9 kg.
  6. Broca-Brugsch (outside the headline range): (170 − 100) × 0.9 = 63.0 kg.

The ideal weight range for this height runs from 65.2 kg to 66.9 kg (Robinson to Hamwi) — the formulas differ by only about 2.7% here, so the result is tight. For comparison, the healthy BMI weight range at 170 cm runs from 53.5 kg to 72.0 kg — noticeably wider, because BMI doesn’t distinguish between sexes or body frames.

Ideal weight range by height, sex and frame size

A few worked examples — the exact figures the calculator returns:

Height Sex Frame size Ideal weight range
140 cm male medium 34.8 – 49.3 kg
152.4 cm male medium 48.1 – 56.2 kg
170 cm male medium 65.2 – 66.9 kg
200 cm male medium 82.6 – 99.1 kg
160 cm female medium 52.1 – 57.2 kg
165 cm female small 50.9 – 59.8 kg
165 cm female large 56.9 – 62.3 kg

The last two rows show how the frame-size adjustment works: at the same height (165 cm) and sex, moving from a small to a large frame shifts the lower bound of the range from 50.9 kg to 56.9 kg — because only the Hamwi result changes, and it’s the one setting that boundary.

At the extremes — below 152.4 cm and at 200 cm and above — the formulas spread further apart (around a 34.5% gap at 140 cm). The calculator flags this with a message: treat a wide range like that as a rough estimate, not a precise target.

Ideal weight vs the healthy BMI range

“Ideal weight” and “healthy BMI range” are two different things that are easy to mix up:

  • Healthy BMI range is the 18.5–24.9 BMI band, converted into kilograms for your height. It depends only on height — not on sex or frame size.
  • Ideal weight (this calculator) is a narrower, more specific estimate from five named historical formulas that account for sex, and optionally frame size.

The healthy BMI range is usually wider than the ideal weight range, because BMI is deliberately built to cover the whole adult population, while the ideal weight formulas try to narrow it down for a specific sex.

Height Healthy BMI range (18.5–24.9)
152.4 cm 43.0 – 57.8 kg
160 cm 47.4 – 63.7 kg
170 cm 53.5 – 72.0 kg
180 cm 59.9 – 80.7 kg

Example: at 180 cm and 75 kg, the calculator shows you’re within the healthy BMI range (59.9–80.7 kg) — and at the same time, you can see how that same weight compares to the ideal weight range calculated for your sex. If all you need is the general WHO weight category, the BMI calculator is the simpler tool.

Frequently asked questions

How do you calculate ideal body weight?

Ideal body weight is calculated with several independent formulas — Devine, Robinson, Miller and Hamwi — that take your height in inches above a 152.4 cm baseline, plus your sex, and return an estimated weight in kilograms. It’s more useful to read this as a range than a single number: for a 170 cm man, it runs from 65.2 kg to 66.9 kg. A fifth, older and less precise formula, Broca-Brugsch (1871), is shown separately.

What’s the difference between ideal weight and a healthy BMI range?

The healthy BMI range (18.5–24.9 BMI) depends only on height and is wider, because it’s meant to cover the whole adult population. Ideal weight, from this calculator, is narrower because it also factors in sex and comes from specific, named historical formulas rather than the general body-mass-index formula.

Which ideal weight formula is most accurate?

None of the five is clearly “best” — they were built in different decades for different purposes (drug dosing, insurance tables, dietetic practice) using different populations, so they return different numbers for the same height. The gap between formulas can be small (about 2.7% for a 170 cm man) or large (over 34% at 140 cm). That’s why the calculator shows a range instead of one figure, and flags it separately when the spread is unusually wide.

How much should I weigh for my height?

It depends on your height and sex. For example, a 170 cm man falls in the 65.2–66.9 kg range across the four main formulas, while a 160 cm woman falls in 52.1–57.2 kg. Enter your own height and sex above to see your exact range, including the result from each of the five formulas individually.

Does ideal weight account for age and gender?

Sex, yes — all five formulas use separate constants for men and women. Age, no — none of these formulas factor it in; they were built for adults generally and don’t distinguish, say, a 25-year-old from a 55-year-old. Body composition does change with age (muscle mass typically declines), so the exact same weight can mean something different at different ages, even though the formula returns the same number.

Is ideal body weight the same as BMI?

No. The healthy BMI range (18.5–24.9) depends only on height and is broader, covering the entire adult population. Ideal weight from this calculator is narrower because it also factors in sex and comes from named historical formulas rather than the general BMI formula.

Does muscle mass affect ideal weight calculations?

No. All five formulas use only height and sex (plus an optional, subjective frame-size setting that adjusts just the Hamwi formula) — none of them measure or estimate muscle tissue. A very muscular person can weigh well above their ideal weight range while carrying very little body fat. For a clearer picture in that case, the body fat calculator is more informative.

Why were these ideal body weight formulas originally created?

Not from research into an “ideal” look, but from practical needs in medicine and insurance. The Devine formula, from 1974, was originally created for drug dosing in patients whose weight fell outside typical ranges. Robinson and Miller (1983) are independent refinements built on broader data, Hamwi (1964) comes from dietetic practice, and Broca-Brugsch (1871) is the oldest of the five, tracing back to 19th-century French tables.

How accurate are ideal weight calculators?

These are historical estimation formulas, not clinical measurements — they don’t account for muscle mass or body frame beyond one subjective adjustment. That’s why this calculator shows a range from four formulas rather than a single number, and flags it separately when the formulas disagree by more than about 10%. Treat the result as a starting point for a conversation with a doctor or dietitian, not a rigid target.

Sources