Ideal Weight Calculator
Estimate a healthy target weight for your height.
A guide only (Devine formula + healthy BMI range). Bodies differ — consult a professional.
What an Ideal Weight Calculator Tells You
This calculator estimates an ideal body weight (IBW) based on your height and gender, and shows the healthy weight range that corresponds to a normal body mass index (BMI). It draws on classic clinical formulas originally developed to guide medication dosing and quick bedside estimates.
There is no single perfect weight for any individual. Two people of the same height can both be healthy at different weights depending on muscle mass, frame size, age, and body composition. Treat the number this tool produces as a reference point and a starting place for conversation, not a fixed goal you must hit.
The calculator gives you two useful outputs: a single IBW estimate from established formulas, and a healthy weight range derived from the normal BMI band. The range is often more meaningful, because it acknowledges that good health spans a span of weights rather than one exact figure.
The Formulas: Devine and Robinson
The most widely cited IBW formula is the Devine formula, which uses height in inches above five feet:
- Men: 50 kg + 2.3 kg for each inch over 5 feet
- Women: 45.5 kg + 2.3 kg for each inch over 5 feet
The Robinson formula is a refinement that often yields slightly lower estimates:
- Men: 52 kg + 1.9 kg for each inch over 5 feet
- Women: 49 kg + 1.7 kg for each inch over 5 feet
Both formulas only use height and gender, so they cannot account for your build or muscularity. That limitation is exactly why pairing them with a BMI-based range gives a fuller picture.
The Healthy BMI Range
Body mass index is weight in kilograms divided by height in metres squared (kg/m²). A BMI between 18.5 and 24.9 is generally classified as a healthy weight for adults.
To turn that into a weight range, the calculator rearranges the formula:
Weight = BMI × height² (in metres)
For someone 1.75 m tall, the healthy range works out to roughly 56.7 kg (18.5 × 1.75²) to 76.3 kg (24.9 × 1.75²). This range is wide on purpose: it reflects that healthy bodies come in many sizes at the same height.
A Worked Example and Its Limits
Consider a man who is 5 feet 10 inches tall, which is 10 inches over 5 feet.
- Devine: 50 + (2.3 × 10) = 73 kg
- Robinson: 52 + (1.9 × 10) = 71 kg
His healthy BMI range for that height (about 1.78 m) spans roughly 58.6 kg to 78.9 kg. The formula estimates fall comfortably inside that band.
These tools were never designed to capture athletic builds, differing frame sizes, or changes that come with age. A muscular athlete may exceed the IBW figure while being very healthy, and an older adult may sit at a different optimal point. For personalized guidance on a target weight, body composition, or any weight-related health concern, consult a doctor or registered dietitian.
Frequently Asked Questions
Not exactly. Ideal body weight is a single estimate from a formula using only height and gender, while a healthy weight is a range that allows for differences in muscle, frame, and body composition. The BMI-based range in this calculator is usually a better real-world reference than one fixed number.
They use different baseline weights and per-inch increments, so they produce slightly different estimates for the same person. Devine tends to give a marginally higher figure. Neither is definitively correct; together they show a reasonable span rather than one absolute target.
No. Both the formulas and BMI rely only on height, weight, and gender, so a muscular person may appear above their ideal weight despite low body fat. If you have significant muscle mass, consider a body-fat or body-composition assessment for a clearer picture.
BMI is a useful population-level screening tool, but it does not measure body fat directly and can misclassify athletes, older adults, and some ethnic groups. Use it as one input among several, and discuss your individual results with a healthcare professional.
Falling slightly outside the range is not automatically a problem, but a persistent gap may be worth discussing with a clinician. They can assess your overall health, not just your weight, and recommend a sensible, sustainable plan if any change is appropriate.
Treat it as a guide rather than a strict goal. A realistic, healthy target depends on your body composition, activity, medical history, and personal circumstances. A doctor or registered dietitian can help you set a goal that is right for you.