Ideal Weight
4 evidence-based formulas
The Ideal Weight Calculator is a clean health tool designed to estimate healthy weight ranges based on your gender and height. By implementing the four most common medical formulas—Devine, Robinson, Miller, and Hamwi—alongside standard BMI limits, it provides a comprehensive comparison of body weight targets, supporting your personal health planning.
Determining a "perfect" body weight is complex. Different formulas were historically developed for clinical applications, and they yield slightly different targets. This calculator presents all four models side-by-side, plus the healthy BMI range, giving you a balanced view of target weights rather than a single number.
This tool runs entirely locally in your web browser. No private height, weight, or personal details are sent over the internet, protecting your privacy. It is a secure, fast, and free tool built to support your medical, fitness, or budgeting goals.
What this ideal weight calculator computes
This calculator estimates healthy weight benchmarks based on your inputs. The primary result is a comparative table showing the estimated weight targets for the four classic formulas: Devine, Robinson, Miller, and Hamwi, presented in both pounds and kilograms.
The results also display the healthy weight range based on standard BMI values (18.5 to 24.9). This range is a valuable comparison, illustrating that healthy body weights are a broad spectrum rather than a single static number. Adjusting your height updates all targets instantly, allowing you to see the differences between formulas.
The height-adjusted base equations
The calculations are based on standard clinical formulas that establish a baseline weight for an individual standing 5 feet (60 inches) tall, with incremental adjustments for each additional inch of height:
- Devine Formula (1974):
- Men:
50.0 kg + 2.3 kg per inch over 5 feet - Women:
45.5 kg + 2.3 kg per inch over 5 feet
- Men:
- Robinson Formula (1983):
- Men:
52.0 kg + 1.9 kg per inch over 5 feet - Women:
49.0 kg + 1.7 kg per inch over 5 feet
- Men:
- Miller Formula (1983):
- Men:
56.2 kg + 1.41 kg per inch over 5 feet - Women:
53.1 kg + 1.36 kg per inch over 5 feet
- Men:
- Hamwi Formula (1964):
- Men:
48.0 kg (106 lbs) + 2.7 kg (6 lbs) per inch over 5 feet - Women:
45.0 kg (100 lbs) + 2.2 kg (5 lbs) per inch over 5 feet
- Men:
These variations reflect differences in how the original researchers adjusted for height and gender, which accounts for the variations in their outputs.
Worked example of target weight
Let us look at a practical example: estimating the ideal weight for a female standing 5 feet 6 inches (66 inches) tall. The height exceeds the 5-foot baseline by exactly 6 inches:
- Devine Calculation:
45.5 kg + (2.3 kg × 6) = 45.5 + 13.8 = 59.3 kg(130.7 lbs). - Robinson Calculation:
49.0 kg + (1.7 kg × 6) = 49.0 + 10.2 = 59.2 kg(130.5 lbs). - Miller Calculation:
53.1 kg + (1.36 kg × 6) = 53.1 + 8.16 = 61.26 kg(135.1 lbs). - Hamwi Calculation:
45.0 kg + (2.2 kg × 6) = 45.0 + 13.2 = 58.2 kg(128.3 lbs). - BMI Healthy Range: 114.6 lbs to 154.3 lbs.
This comparison shows that the formulas suggest target weights between 128 lbs and 135 lbs, which fall comfortably within the healthy BMI range of 115 lbs to 154 lbs, illustrating the spectrum of healthy weight targets.
When to use this calculator
Use this calculator as a general reference when planning weight management goals with a nutritionist or healthcare professional. In clinical medicine, these formulas are historically used to calculate medication dosages (especially for drugs that distribute primarily in lean tissue) and ventilator settings. They serve as a standardized baseline across clinical settings.
The comparative layout is ideal for understanding how the different models differ. It helps you avoid focusing on a single number, showing that a healthy weight is a flexible range determined by your body structure, health, and personal fitness.
Important clinical considerations
It is important to emphasize that these formulas estimate average weight targets based on height and gender alone. They do not account for muscle mass, bone structure, body fat distribution, overall health, or age. A highly muscular person or someone with a large frame will weigh more than these formulas suggest, while remaining healthy.
Additionally, these formulas do not apply to children, pregnant women, or competitive athletes with unusual body compositions. Do not treat these numbers as absolute medical goals. Always discuss weight targets and physical health with your primary care provider.
Frequently asked questions
Which formula is "right"?
None is uniquely right — all are reasonable estimates. Take the range across all four as a directional target rather than treating any single number as the goal.
Does the result vary by frame size?
These formulas do not directly account for frame size. Smaller-framed individuals may be slightly under the calculated weight, larger-framed slightly over, both at the same body composition.
Is "ideal" the same as "healthy"?
Not exactly. The formulas predict a weight associated with low mortality in mid-twentieth-century data. A healthy weight today is best assessed by a clinician using multiple indicators.
Why do different formulas show different target weights?
Each formula was developed by different researchers analyzing different clinical datasets. The differences in their incremental rates reflect variations in their underlying populations and analytical methods.
How does frame size affect ideal weight estimates?
These standard formulas do not adjust for frame size. In clinical practice, clinicians adjust ideal weight targets up or down by 10% to account for variations in skeletal structure and bone density.