Numarly

Ideal Body Weight Calculator

Compare your ideal weight across four widely used medical formulas.

Gender

What is it?

This calculator estimates your ideal body weight using four widely referenced medical formulas — Devine, Robinson, Miller, and Hamwi — so you can compare results instead of relying on just one estimate.

Formula

Devine (male) = 50 + 2.3 × (height in inches − 60)
Devine (female) = 45.5 + 2.3 × (height in inches − 60)

Formula Explanation

Each formula sets a baseline weight for 5 feet (60 inches) of height, then adds a fixed amount per inch above that. The formulas differ slightly in their baseline and per-inch multiplier, which is why they produce a small range of values rather than one exact number — no single formula is universally the most accurate.

Example Calculation

A man who is 5'10" (70 inches) tall has a Devine ideal weight of 50 + 2.3 × (70 − 60) = 73 kg (about 161 lbs), while the Robinson formula gives roughly 71 kg for the same height.

How to Use

  1. Select your gender.
  2. Enter your height in centimeters, or feet and inches.
  3. Compare your ideal weight across all four formulas, plus the average.

Benefits

  • Shows four formulas side by side instead of a single number, giving a more honest range.
  • Useful starting point for setting realistic weight goals with a doctor or dietitian.
  • Works with both metric and imperial height units.

Use Cases

  • Getting a general target weight range before starting a fitness or nutrition plan.
  • Comparing ideal weight formulas used in different clinical dosing calculations.
  • Cross-checking BMI-based weight guidance with formula-based estimates.

What Your Result Means

These formulas were originally developed for estimating medication dosages, not as fitness targets. They give a reasonable reference range based on height alone, but don't account for muscle mass, frame size, or body composition — treat the range, not any single number, as the useful output.

Tips

  • Use the range across all four formulas rather than fixating on one exact figure.
  • Combine this with body fat percentage or BMI for a fuller picture of healthy weight.
  • Athletes and very muscular individuals will often exceed these estimates while still being healthy.

Common Mistakes

  • Treating the result as a strict target rather than a general reference range.
  • Using these formulas for children — they're validated for adults only.
  • Ignoring frame size and muscle mass, which these height-only formulas can't account for.

FAQs

Which ideal weight formula is most accurate?

No single formula is universally most accurate — they were developed decades apart for drug-dosing purposes and typically agree within a few kilograms of each other.

Why do the formulas give different results?

Each was derived from different population data and uses a slightly different baseline weight and per-inch multiplier, producing a small spread rather than one fixed answer.

Is ideal body weight the same as a healthy weight?

Not exactly — these formulas estimate a reference weight based on height alone, while a healthy weight also depends on muscle mass, body fat, and overall fitness.

Can I use this for children?

No, all four formulas were validated on adults; children need pediatric growth charts instead.

This tool is for educational and informational purposes only and is not medical advice.

Last updated: July 26, 2026