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Ideal Weight Calculator

Estimate ideal body weight using Devine, Robinson and Hamwi formulas.

cm

About the Ideal Weight Calculator

This ideal weight calculator estimates a 'healthy' target body weight using four historical formulas developed between 1964 and 1983: Devine, Robinson, Hamwi, and Miller. Enter your height and gender, and the tool returns the ideal weight predicted by each formula, plus their average — giving you a range to consider rather than a single absolute number.

These formulas were developed for use in clinical dosing of medications (where weight-based dosing needed a reference for patients whose actual weight was unknown) and have been adopted as rough targets in nutrition and fitness. They share a common structure: a base weight for someone who is 5 feet (152 cm) tall, plus a per-inch increment for additional height. The coefficients vary by formula based on the populations each was derived from.

None of these formulas is 'correct' — they are all approximations based on 1970s-1980s populations, when average body weights were lower than today. Use the results as a rough target range, not as a mandate. Modern clinical practice typically uses BMI 18.5-24.9 as the 'healthy weight' range, which gives a wider target than the historical formulas.

How It Works

All four formulas use the structure: ideal_weight = base + increment * (height_inches - 60), where the per-inch increment applies only to inches above 5 feet (60 inches).

The four formulas:

Devine (1974): Men = 50 + 2.3*(in-60), Women = 45.5 + 2.3*(in-60); Robinson (1983): Men = 52 + 1.9*(in-60), Women = 49 + 1.7*(in-60); Hamwi (1964): Men = 48 + 2.7*(in-60), Women = 45.5 + 2.2*(in-60); Miller (1983): Men = 56.2 + 1.41*(in-60), Women = 53.1 + 1.36*(in-60)

For someone 175 cm tall (68.9 inches, 8.9 inches above 5'0):

  • Devine (male): 50 + 2.3 * 8.9 = 70.5 kg
  • Robinson (male): 52 + 1.9 * 8.9 = 68.9 kg
  • Hamwi (male): 48 + 2.7 * 8.9 = 72.0 kg
  • Miller (male): 56.2 + 1.41 * 8.9 = 68.7 kg

For comparison, the BMI 18.5-24.9 healthy range for 175 cm is 56.6-76.2 kg — wider and overlapping with the four formula estimates.

Worked Examples

For a 175 cm (5'9") male:

  1. Height in inches: 175 / 2.54 = 68.9 in
  2. Inches above 5 feet: 68.9 - 60 = 8.9
  3. Devine: 50 + 2.3 * 8.9 = 70.5 kg
  4. Robinson: 52 + 1.9 * 8.9 = 68.9 kg
  5. Hamwi: 48 + 2.7 * 8.9 = 72.0 kg
  6. Miller: 56.2 + 1.41 * 8.9 = 68.7 kg
  7. Average: 70.0 kg
  8. BMI healthy range (18.5-24.9): 56.6 - 76.2 kg

For a 165 cm (5'5") female:

  1. Height in inches: 165 / 2.54 = 65.0 in
  2. Inches above 5 feet: 5.0
  3. Devine: 45.5 + 2.3 * 5.0 = 57.0 kg
  4. Robinson: 49 + 1.7 * 5.0 = 57.5 kg
  5. Hamwi: 45.5 + 2.2 * 5.0 = 56.5 kg
  6. Miller: 53.1 + 1.36 * 5.0 = 59.9 kg
  7. Average: 57.7 kg

When to Use This Tool

Use this ideal weight calculator when:

  • Setting a target weight for a weight-loss or weight-gain program
  • Comparing your current weight to historical clinical reference ranges
  • Estimating a goal weight when only height is known
  • Comparing formula estimates against the BMI healthy range
  • Calculating weight-based medication dosing when actual weight is unavailable
  • Educational use: demonstrating how ideal weight concepts evolved over time
  • Demonstrating the difference between older clinical formulas and modern BMI guidance

The BMI 18.5-24.9 healthy weight range is the modern clinical standard and is recommended over the historical formulas for most purposes. Use our BMI Calculator for that approach.

Limitations & Disclaimer

This calculator applies four historical ideal-weight formulas (Devine 1974, Robinson 1983, Hamwi 1964, Miller 1983) derived from predominantly Caucasian American populations in the mid-20th century. The formulas do not account for body composition (muscle vs fat), frame size (small, medium, large), age, activity level, or ethnicity-specific body composition patterns. They produce single point estimates that vary by 2-5 kg across the four formulas, suggesting inherent uncertainty. Modern clinical practice generally prefers the BMI 18.5-24.9 healthy weight range, which is wider and population-based. The formulas are most useful for clinical medication dosing when actual body weight is unavailable, not for setting individual weight-loss targets. This is an educational tool, not medical advice. See our disclaimer for full terms.

Frequently Asked Questions

Which formula is most accurate?

None is definitively 'most accurate' — they were derived from different populations in different eras and produce slightly different estimates. The Devine formula is the most widely cited and used in clinical dosing. The Miller formula gives the lowest estimates (it was based on insurance actuarial data from the 1980s). The average of all four is a reasonable compromise.

Are these formulas still used in medicine?

Yes — the Devine formula is still used for weight-based medication dosing (especially in chemotherapy and certain antibiotics) when actual body weight is unavailable. However, most clinical nutrition guidance now uses BMI 18.5-24.9 as the healthy weight range, which is broader and population-based rather than formula-derived.

Why do these formulas give a single number rather than a range?

Each formula gives a single point estimate. Our calculator shows the range across all four formulas plus the average. The BMI healthy weight range (56.6-76.2 kg for 175 cm) is much wider and reflects the population-level variation in healthy body composition.

Do these formulas apply to athletes or bodybuilders?

Not well. The formulas assume average body composition and may underestimate ideal weight for muscular individuals. A 175 cm male bodybuilder at 80 kg with 12% body fat is well above the formula estimates (68-72 kg) but is in excellent health — the formulas do not account for muscle mass.

Do these formulas apply to older adults?

Less reliably. Older adults naturally carry less muscle and more fat at any given weight, and the formulas were derived from younger populations. Some geriatric guidelines suggest slightly higher target weights (BMI 23-27) for older adults to account for the protective effect of modest extra weight in this population.

Are these formulas applicable to non-Caucasian populations?

The formulas were derived from predominantly Caucasian American populations. Asian populations tend to have lower healthy weights at the same height, and African populations may have higher healthy weights. For non-Caucasian individuals, the BMI healthy range (with WHO Asian-specific cut-offs) is more appropriate than these historical formulas.

Last updated: July 21, 2026  ·  Author: HT99 Tools Editorial Team  ·  Reviewed by: HT99 Tools Editorial Team