Healthy Weight Range by Height: Formulas & Calculation
What is the right weight range for your height? Learn the reverse-engineering math behind healthy BMI bounds and how clinicians determine Ideal Body Weight.
AllCalcNow Editorial Team
Published June 26, 2026
When evaluating physical fitness and health risks, standard charts often list a target weight range for given heights. These ranges serve as primary guidelines for medical screenings, insurance evaluations, and clinical checkups.
But how are these numbers actually derived? Instead of relying on random estimations, health organizations like the World Health Organization (WHO) use standardized mathematical models. By reverse-engineering the Body Mass Index (BMI) equation, we can calculate the exact boundary weights that correspond to normal, underweight, overweight, and obese classifications. Additionally, researchers have developed formulas to pinpoint a specific "Ideal Body Weight" (IBW) for clinical dosage calculations. This guide breaks down the mathematics of healthy weight ranges, explains the formulas in detail, and walks through worked step-by-step examples.
Calculating Healthy Weight Limits via Reverse BMI
To find the boundaries of a healthy weight range, we start with the standard BMI formula. BMI is calculated as weight divided by squared height. By rearranging the variables, we can solve for weight at the critical BMI boundaries (specifically, 18.5 for the lower normal limit and 24.9 for the upper normal limit).
1. The Metric Reverse Formula
Using metric units (weight in kilograms, height in meters), the formula is straightforward:
Weight (kg) = Target BMI * [ Height (m) ]^2 2. The Imperial Reverse Formula
Using imperial units (weight in pounds, height in inches), we must include the standard conversion factor of 703:
Weight (lbs) = ( Target BMI * [ Height (in) ]^2 ) / 703 Find Your Healthy Weight Range automatically
Skip the reverse squaring equations. Enter your height into our interactive BMI Calculator to see your healthy weight bounds and weight classifications instantly.
Determining Ideal Body Weight: The Devine Formula
While the reverse BMI equation yields a broad weight range, clinicians often require a single reference weight. This is known as the Ideal Body Weight (IBW). Initially developed by Dr. Ben Devine in 1974 for medical clearance and medication dosing (such as clearance of water-soluble drugs), the Devine formulas are the standard benchmark in clinical practice.
The Devine formula assumes a baseline weight for a height of 5 feet (60 inches) and adds a specific increment for each additional inch:
Devine Formula for Men
IBW (kg) = 50.0 + 2.3 * ( Height (in) - 60 ) Devine Formula for Women
IBW (kg) = 45.5 + 2.3 * ( Height (in) - 60 ) Step-by-Step Calculation Examples
Let's perform step-by-step arithmetic for two different scenarios.
Example 1: Finding Healthy Weight Range for a Height of 5'10"
We want to find the WHO normal weight range (BMI 18.5 to 24.9) for an individual who is 5 feet 10 inches tall.
- Convert height to inches: 5 feet * 12 inches/foot + 10 inches = 70 inches.
- Calculate the lower weight limit (BMI = 18.5):
Lower Weight = (18.5 * 70^2) / 703
Lower Weight = (18.5 * 4900) / 703 = 90650 / 703 ≈ 128.95 lbs - Calculate the upper weight limit (BMI = 24.9):
Upper Weight = (24.9 * 70^2) / 703
Upper Weight = (24.9 * 4900) / 703 = 122010 / 703 ≈ 173.56 lbs
A person standing 5'10" has a normal, healthy weight range of approximately 129 to 174 pounds.
Example 2: Ideal Body Weight (IBW) for a 6'0" Male
We want to calculate the Ideal Body Weight for a male who is 6 feet tall using the Devine formula.
- Convert height to inches: 6 feet * 12 inches/foot = 72 inches.
- Calculate height inches above 60: 72 - 60 = 12 inches.
- Apply the Devine formula:
IBW = 50.0 + 2.3 * 12
IBW = 50.0 + 27.6 = 77.6 kg - Optional (Convert to pounds):
IBW (lbs) = 77.6 kg * 2.20462 ≈ 171.1 lbs
The ideal body weight for a 6'0" male is approximately 77.6 kg (171.1 lbs).
Normal BMI Weight Ranges (Imperial)
| Height | Normal Range (18.5 - 24.9 BMI) | Male Devine IBW | Female Devine IBW |
|---|---|---|---|
| 5'4" (64 inches) | 108 – 145 lbs | 130.5 lbs (59.2 kg) | 120.6 lbs (54.7 kg) |
| 5'7" (67 inches) | 118 – 159 lbs | 145.7 lbs (66.1 kg) | 135.8 lbs (61.6 kg) |
| 5'10" (70 inches) | 129 – 174 lbs | 160.9 lbs (73.0 kg) | 151.0 lbs (68.5 kg) |
| 6'1" (73 inches) | 140 – 189 lbs | 176.1 lbs (79.9 kg) | 166.2 lbs (75.4 kg) |
Limitations of Ideal Weight Calculations
When using these equations, keep these essential caveats in mind:
- Frame Size Adjustments: The Devine formula does not account for skeleton frame width. Individuals with broad frames naturally carry more bone and muscle tissue, making their actual healthy weight higher than the formula's prediction.
- Age Factors: A healthy weight range naturally shifts as we age. For older adults, carrying a slightly higher BMI (such as 25.0 to 27.0) is often associated with better health outcomes and protection against bone loss.
- Athletic Muscle Mass: The reverse BMI boundaries will incorrectly label athletes carrying high muscle mass as overweight or obese. Under such conditions, body fat percentage and waist circumference measurements are superior tracking tools.
Use these calculated weight ranges as a flexible baseline. Focus on body composition, metabolic markers, and overall functional fitness to define your optimal personal health target.
Frequently Asked Questions
How is the healthy weight range for my height calculated?
It is calculated by reverse-engineering the BMI formula: multiplying the target healthy BMI thresholds (18.5 and 24.9) by your squared height.
What is the Devine formula?
The Devine formula is a mathematical equation used by clinicians to estimate a patient's Ideal Body Weight. It calculates a baseline weight for a height of 5 feet and adds a fixed amount of weight for each additional inch of height.
Should children use these ideal weight formulas?
No. These adult formulas are inappropriate for pediatric populations. For children and adolescents, clinicians track growth percentiles relative to age-based developmental charts.