Ideal Weight Calculator: Devine & Robinson

Ideal weight by formula compared to BMI healthy range
Formula	Use	Ideal
Robinson	Dosing	69 kg
Miller	Clinical	69 kg
Devine	Clearance	70 kg
Hamwi	Wellness	72 kg
BMI 18.5–25	Broad	57 - 77 kg

Ideal weight calculator: Robinson, Miller, Devine, and Hamwi

This calculator compares four ideal body weight (IBW) formulas, their average, optional frame bands, and a BMI 18.5–25 weight span at your height. Clinical reference only; not medical advice.

What this calculator does

The widget computes ideal body weight (IBW) from Robinson (1983), Miller (1983), Devine (1974), and Hamwi (1964) using height and sex. It shows the four-formula average on the dark results card, optional frame-adjusted bands in the comparison table, and a BMI 18.5–25 weight span on the same row. It does not measure body fat, waist size, or pediatric growth and is not a prescription for how much you should weigh.

Robinson (male example):

$\text{kg} = 52 + 1.9 \times (\text{height (in)} - 60)$
BMI healthy band:

$\text{kg} = \text{BMI} \times \text{height (m)}^2$ for BMI 18.5 and 25.0

How the math works

Each formula converts height to total inches, subtracts 60 inches (five feet), and applies sex-specific coefficients. With default input 175 cm (about 69 inches) and male selected, inches over five feet equal 9. Robinson returns 52 + (1.9 × 9) ≈ 69 kg; Miller ≈ 69 kg; Devine ≈ 71 kg; Hamwi ≈ 72 kg. The widget averages those four values to about 70 kg (154 lb) on the results card.

The BMI 18.5–25 row multiplies each cutoff by height in meters squared. At 1.75 m, 18.5 × 1.75² ≈ 57 kg and 25 × 1.75² ≈ 77 kg, shown as the green band in the table. Choosing a frame size applies a percentage band around each formula (small about −10% to −5%, large about +5% to +10%) and updates the dark panel subtitle.

At 70 inches (5′10″) male, Robinson ≈ 157 lb, Miller ≈ 155 lb, Devine ≈ 161 lb, Hamwi ≈ 165 lb, with an average near 159 lb. At 68 inches (5′8″) female, the four formulas cluster near 138–141 lb with an average near 140 lb. These examples match the table when you enter those heights.

Limits of the model

Hospital protocols cite Devine and Robinson for renal and antibiotic dosing; this page compares all four for context, not to pick one clinical protocol. Frame bands adjust for bone structure, not muscle mass. Muscular adults often weigh above every IBW line while staying healthy. The age field does not change formulas. Ask a clinician for personal targets; these equations are educational screening only.

FAQ

Which ideal weight formula is most accurate?

None is universally best. The widget computes all four formulas and shows them in the Model comparison table in section 02. At one height they usually spread about 5–15 lb (2–7 kg). The dark panel highlights the four-formula average so you see the cluster instead of betting on one equation.

What should I weigh for my height?

Enter height and sex in section 01 Measurements, then compare the four-formula average on the dark results card to the green BMI 18.5–25 row in the table. Ideal body weight (IBW) lines are historical point estimates from dosing literature; the BMI row is the wider screening band at the same height.

What is ideal weight for a 5′10″ male?

At 70 inches (5′10″), the widget shows Robinson 157 lb, Miller 155 lb, Devine 161 lb, and Hamwi 165 lb on the comparison table (average ≈ 159 lb / 72 kg). The green BMI 18.5–25 row at that height is roughly 129–174 lb. Choosing a frame size applies a band around each value.

What is ideal weight for a 5′8″ female?

At 68 inches (5′8″), female formulas land near Robinson 138 lb, Miller 141 lb, Devine 141 lb, Hamwi 139 lb (average ≈ 140 lb / 64 kg). The BMI 18.5–25 row is roughly 121–164 lb at the same height.

Does muscle mass affect my ideal weight?

Yes. All four formulas use height and sex only. A lifter can weigh above every IBW line and still be healthy. This calculator does not measure body fat or lean mass; treat formula outputs as historical reference points, not a target for muscular adults.

What is body frame size and how do I measure it?

Frame size estimates bone structure from wrist circumference at the narrowest point below the hand bone. Tap Wrist measurement guide under Frame (optional) for sex-specific thresholds. Men: small <6.5 in, medium 6.5–7.5 in, large >7.5 in. Women: small <5.5 in, medium 5.5–6.5 in, large >6.5 in. Selecting Small, Medium, or Large scales each formula into a band in the table.

Does age change the formula results?

The four formulas ignore age. The Age field in section 01 is for your records only and does not change Robinson, Miller, Devine, or Hamwi outputs. Older adults often care more about body composition than a dosing-era target weight.

What is the difference between ideal weight and healthy weight?

Ideal body weight (IBW) equations return single numbers from clinical literature, often for drug dosing. The green BMI 18.5–25 row in the Model comparison table converts that screening band to kilograms or pounds at your height. Most IBW results fall inside that band, but the band is the broader population screen.

Ideal Weight Calculator

Measurements

Results

Model comparison

Disclaimer

How to use this calculator

Reading the four-formula comparison

Example: 175 cm, male (default metric)

Why the formulas disagree

Frame size adds a band

IBW formulas vs BMI row in the table