Ideal Weight Calculator — Healthy Range for Your Height, 4 Formulas (2026)

Your healthy weight range from the BMI 18.5–24.9 band plus four classic clinical formulas (Devine, Robinson, Miller, Hamwi) — shown side by side with honest caveats. Free, no signup.

There is no single 'ideal' weight — there's a healthy range, and four decades-old clinical formulas that land at different points inside (and sometimes outside) it. Enter five details and see the honest picture: the BMI-based range for your height, the four classic estimates, and where you stand today.

Why the formulas disagree

Devine (1974) was built for drug dosing, Hamwi (1964) for quick clinical estimation, and Robinson and Miller (1983) as refinements of Devine against actuarial data. None was designed as a health target — which is why they can spread 5+ kg apart for the same person and why we show all four instead of averaging away the disagreement.

The healthy-BMI band is the more defensible reference: it's the weight range associated with the lowest population-level health risk for your height. It's also wide — usually 15–20 kg — which is the honest amount of room individual healthy weights occupy.

What to do with the number

If you're inside the band: weight alone is a weak reason to change anything — energy, strength, labs, and habits tell you more. If you're outside it, direction matters more than distance: a sustained, modest change of even 5% of body weight measurably improves most health markers.

Set the eating side with tools that respect both the science and your life: the calorie-deficit calculator for the target, and the MyPlate Plan for what the target looks like as food.

Formula & sources

Devine (1974)

IBW={50.0+2.3 xmale45.5+2.3 xfemale\text{IBW} = \begin{cases} 50.0 + 2.3\,x & \text{male} \\[2pt] 45.5 + 2.3\,x & \text{female} \end{cases}

Robinson (1983)

IBW={52.0+1.9 xmale49.0+1.7 xfemale\text{IBW} = \begin{cases} 52.0 + 1.9\,x & \text{male} \\[2pt] 49.0 + 1.7\,x & \text{female} \end{cases}

Miller (1983)

IBW={56.2+1.41 xmale53.1+1.36 xfemale\text{IBW} = \begin{cases} 56.2 + 1.41\,x & \text{male} \\[2pt] 53.1 + 1.36\,x & \text{female} \end{cases}

Hamwi (1964)

IBW={48.0+2.7 xmale45.5+2.2 xfemale\text{IBW} = \begin{cases} 48.0 + 2.7\,x & \text{male} \\[2pt] 45.5 + 2.2\,x & \text{female} \end{cases}

Healthy-BMI weight band

weight range={18.5, 24.9}×[height (m)]2\text{weight range} = \{18.5,\ 24.9\} \times [\text{height (m)}]^2

IBW in kg; x = inches of height above 5 ft (60 in). The headline is the healthy-BMI band; the four clinical formulas are shown for comparison.

Sources

  • Devine BJ (1974) Gentamicin therapy. Drug Intell Clin Pharm 8:650–655.
  • Robinson JD, et al. (1983) Determination of ideal body weight for drug dosage calculations. Am J Hosp Pharm 40(6):1016–1019.
  • Miller DR, et al. (1983) Determining ideal body weight (and mass). Am J Hosp Pharm / Drug Intell Clin Pharm 17:544–546.
  • Hamwi GJ (1964) Therapy: changing dietary concepts. In: Diabetes Mellitus: Diagnosis and Treatment. American Diabetes Association.

Ideal weight questions, answered

What is my ideal weight for my height?

A range, not a number: the weights mapping to BMI 18.5–24.9 at your height — this page computes yours. The four clinical formulas land at single points inside that band, and they disagree with each other by design history, not by your biology.

Which ideal-weight formula is most accurate?

None is 'accurate' as a health target — Devine was built for drug dosing, Hamwi for bedside estimation. They're shown because they're widely quoted; the BMI band is the better-evidenced reference for population health.

Is BMI reliable for me?

It's a screening tool with known blind spots: it can't distinguish muscle from fat, so muscular people often read 'above range' at healthy body-fat levels, and it under-flags low muscle mass in older adults. Waist measurements and body composition tell richer stories.

How fast can I reach a healthy weight safely?

The conventional sustainable rate is 0.25–0.5 kg (0.5–1 lb) per week — a 250–500 kcal/day deficit. Our calorie-deficit calculator builds the targets with below-BMR warnings included.

Does age change my ideal weight?

The BMI band is defined for adults generally, but evidence suggests slightly higher BMIs are not harmful — and may be protective — in older adults. After ~65, preserving muscle matters more than chasing the lower half of the range.

Do I need to hit the middle of the range?

No. Anywhere inside the band carries similar population-level risk, and your healthiest weight within it depends on build, history, and what you can maintain while living well. The middle is a statistic, not a prescription.

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