Ideal Weight Calculator

Enter your sex and height to see your ideal body weight from four widely used clinical formulas, plus the average of all four and the healthy weight range implied by a normal BMI. Use it as a reference range, not a strict target.

Average ideal weight70 kg

Devine formula70.5 kg

Robinson formula68.9 kg

Miller formula68.7 kg

Hamwi formula72 kg

Healthy-BMI range from56.7 kg

Healthy-BMI range to76.3 kg

How this calculation works

Devine, Robinson, Miller, and Hamwi are formulas doctors and dietitians have used for decades, originally to help estimate drug dosing. Each starts from a base weight for 5 feet (152.4 cm) of height and adds a fixed amount per inch above that.

For men: Devine = 50 + 2.3 kg per inch over 5 ft; Robinson = 52 + 1.9 kg per inch; Miller = 56.2 + 1.41 kg per inch; Hamwi = 48 + 2.7 kg per inch. For women the base values are lower (45.5, 49, 53.1, 45.5 kg) with slightly different per-inch increments (2.3, 1.7, 1.36, 2.2 kg).

The calculator also reports the weight range that corresponds to a healthy BMI of 18.5–24.9 at your height, since modern guidance leans on BMI range more than any single "ideal" number.

Worked example

A 175 cm tall man is 8.9 inches over 5 ft. Devine gives 50 + 2.3 × 8.9 ≈ 70.5 kg, Robinson ≈ 68.9 kg, Miller ≈ 68.7 kg, and Hamwi ≈ 72.0 kg, averaging to about 70.0 kg. His healthy-BMI range at that height is roughly 56.7–76.3 kg — a much wider, more realistic target than any single formula.

The four classic formulas compared

All four formulas share the same shape — a base weight at 5 ft (152.4 cm) plus a fixed amount per inch of extra height — but were derived differently, which is why they diverge:

Formula	Year	Male base + per inch	Female base + per inch
Hamwi	1964	48 kg + 2.7 kg/in	45.5 kg + 2.2 kg/in
Devine	1974	50 kg + 2.3 kg/in	45.5 kg + 2.3 kg/in
Robinson	1983	52 kg + 1.9 kg/in	49 kg + 1.7 kg/in
Miller	1983	56.2 kg + 1.41 kg/in	53.1 kg + 1.36 kg/in

Why 'ideal weight' is really a range

These formulas were created mainly to standardize medication dosing in clinical settings, not to define a single number every person should aim for. They ignore muscle mass, bone structure, frame size, and body-fat distribution — all of which meaningfully affect what weight is actually healthy for a given person.

For that reason, many clinicians now prefer the healthy-BMI weight range (18.5–24.9 BMI, shown here as bmiRangeLow to bmiRangeHigh) as the more useful reference, since it reflects a broader evidence base tied to health outcomes rather than a single historical formula.

How to use these numbers sensibly

Treat the four formulas and their average as a rough band, not a precise target — a spread of a few kilograms between them is normal and expected.
Prefer the healthy-BMI range for a broader, evidence-based target, especially if you have significant muscle mass.
Combine with body composition — waist circumference or body-fat percentage — for a fuller picture than weight alone.
Consult a doctor or dietitian before using any single number to set a weight-loss or weight-gain goal, especially if you have a medical condition.

Frequently asked questions

Which ideal weight formula is most accurate?

None is definitively "correct" — they were developed decades apart for different clinical purposes, mainly drug dosing, and none accounts for muscle mass, frame size, or body composition. Treat the average as a rough midpoint and the healthy-BMI range as the more defensible target.

Why do the four formulas give different numbers?

Each was derived from a different population and study, so their base weights and per-inch slopes differ slightly. The spread between them (often 2–4 kg) is a useful reminder that 'ideal weight' is inherently approximate.

Is there an ideal weight for children?

No. These formulas apply only to adults. Children and teens are assessed with age-and-sex growth percentile charts instead, since a fixed formula can't capture normal growth variation.

Should I aim for the exact average number?

Not necessarily. Treat the average and the four formulas as a plausible band rather than a precise target. Frame size, muscle mass, ethnicity, and personal health history all shift what's actually healthy for you.

How is this different from the BMI healthy-weight range?

The four classic formulas use height alone with fixed per-inch slopes and were built for dosing estimates. The BMI range instead uses the WHO's evidence-based healthy BMI band (18.5–24.9) applied to your height, which is generally considered the more clinically grounded reference today.

Does this calculator store my height or sex?

No. Everything is calculated locally in your browser and nothing is uploaded, logged, or saved.

What about frame size — small, medium, large?

None of these formulas adjust for frame size directly, though some clinicians apply a manual +/-10% adjustment for a small or large frame. If you have a notably broad or narrow frame, treat the output as a starting point rather than a fixed answer.

This tool is provided for general information only. Verify important figures independently. · Last reviewed: August 25, 2026