Health tool
BMI & Ideal Weight CalculatorBody Mass Index & Formula-Based Weight Targets
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4 formulas
Instant results
Calculate your BMI and ideal body weight in one tool. Enter your height, weight, and sex to instantly see your Body Mass Index score, weight category, and ideal weight estimates from the four most widely used formulas -- Devine, Robinson, Miller, and Hamwi.
Disclaimer: BMI is a screening tool, not a medical diagnosis. Consult a doctor for health advice.
Your Details
Your BMI is 26.1, placing you in the Overweight category. Use the ideal weight section to compare your current weight to formula-based targets for your height and sex.
BMI Score
26.1
Overweight Category
UnderweightNormalOverweightObese
Ideal Weight Estimates
Devine (1974)
70.5 kg
Robinson (1983)
68.9 kg
Miller (1983)
68.7 kg
Hamwi (1964)
72.0 kg
Average Ideal
70.0 kg
You are 10.0 kg above the average ideal weight.
Getting started
How to Use This Combined Calculator
This tool calculates two things at once: your BMI and your ideal body weight.
1
Enter your details
Choose Metric or Imperial, and select your sex (formulas differ by sex).
2
Enter measurements
Type your height and weight into the fields above.
3
Review both metrics
Your BMI score appears alongside four ideal weight estimates.
The calculation
Step-by-step: how your results were calculated
Here is exactly how the calculation works.
1
Convert height and calculate BMI
Height (m) = 175.0 cm / 100 = 1.750 m
BMI = weight (kg) / height² (m)
= 80.0 / 3.0625
= 26.1 (Overweight)
2
Ideal weight: Devine formula (male)
IBW = 50 + 2.3 x (height_in - 60)
IBW = 50 + 2.3 x (68.9 - 60)
= 50 + 20.46
= 70.5 kg
Context
BMI vs Ideal Body Weight: Understanding Both
Key insight: BMI tells you whether your current weight is in a healthy range. Ideal body weight tells you what statistical formulas consider optimal for your height. Used together they give a richer picture.
What BMI answers"Is my current weight proportionate to my height?" -- it gives a category (Normal weight, Overweight, etc.) that can be compared to clinical thresholds.
What Ideal Weight answers"What weight do published formulas suggest is ideal for my height and sex?" -- it gives a specific target number in kg or lbs.
Can I have a normal BMI but be "above ideal"?Yes. IBW formulas target roughly BMI 20 -- 23. A person with BMI 24.5 would have a normal BMI but sit above all four ideal weight estimates. This is common and healthy.
Reference
The Four Ideal Weight Formulas
| Formula | Men (height in inches) | Women (height in inches) |
|---|---|---|
| Devine (1974) | 50 + 2.3 x (ht_in - 60) | 45.5 + 2.3 x (ht_in - 60) |
| Robinson (1983) | 52 + 1.9 x (ht_in - 60) | 49 + 1.7 x (ht_in - 60) |
| Miller (1983) | 56.2 + 1.41 x (ht_in - 60) | 53.1 + 1.36 x (ht_in - 60) |
| Hamwi (1964) | 48 + 2.7 x (ht_in - 60) | 45.4 + 2.27 x (ht_in - 60) |
All formulas use inches above 60 in (5 ft). Results are in kilograms. The average of all four provides a balanced target.
Strategy
Quick Tips for Using BMI and Ideal Weight Together
Use the average
Don't aim for the lowest ideal weight formula result -- the average of all four is a more balanced target.
Consider muscle mass
If you are muscular or athletic, both BMI and IBW will overestimate your health risk -- use body fat percentage as well.
Clinical settings
The Devine formula is used in clinical drug dosing; if a pharmacist mentions ideal weight, they almost certainly mean Devine.
Examples
BMI & Ideal Weight combinations
See how BMI and Ideal Weight targets interact in different scenarios.
Average
Female, 5'4" (163cm), 130lbs
BMI 22.3 vs Target 123lbs
+6.8 lbs
Healthy, slightly above ideal
Tall
Male, 6'2" (188cm), 200lbs
BMI 25.7 vs Target 181lbs
+19.0 lbs
Overweight, above ideal
Underweight
Female, 5'6" (168cm), 110lbs
BMI 17.8 vs Target 132lbs
-22.0 lbs
Underweight, below ideal
FAQ
Frequently asked questions
Q
What does this BMI and ideal weight calculator show?This combined tool calculates two things at once: your current BMI (Body Mass Index) from your height and weight, and your ideal body weight range from four established formulas (Devine, Robinson, Miller, Hamwi). You can immediately see your BMI category alongside how your current weight compares to each ideal weight estimate.
Q
What is the difference between BMI and ideal body weight?BMI is a ratio of weight to height squared -- it gives a number (e.g. 24.5) that is compared to fixed thresholds (18.5 -- 24.9 = normal). Ideal body weight (IBW) formulas predict a specific target weight in kg or lbs based on height and sex. They are related but not identical -- a person can have a normal BMI while being above or below their ideal body weight according to one formula.
Q
Which ideal weight formula should I use?In clinical settings, the Devine formula is the most commonly used -- especially for drug dosing calculations. In dietetics, the Hamwi formula is frequently cited. For general guidance, the average across all four formulas is a balanced approach. All four formulas give broadly similar results for average-height adults, with greater divergence at very short or tall heights.
Q
What is a healthy BMI alongside ideal weight?A healthy adult BMI is 18.5 -- 24.9. Ideal weight formula results typically correspond to a BMI of approximately 20 -- 23 -- within the normal range but on the lower-middle end. If your current weight gives a normal BMI but sits above all four ideal weight estimates, it doesn't necessarily mean you need to lose weight -- it means you are healthy by BMI standards with room to consider body composition.
Q
Can I have a normal BMI and still be overweight relative to ideal weight?Yes. Because IBW formulas target roughly BMI 20 -- 23, a person with BMI 24.5 would have a normal BMI but sit above all four ideal weight estimates. This is common and does not indicate a health problem -- the healthy BMI range extends to 24.9 by design.
Q
Do the ideal weight formulas factor in age?No -- all four formulas use only height and sex. Age is not factored in directly. Some clinicians apply a slight upward adjustment for older adults (particularly 65+), who may benefit from a slightly higher weight for bone protection and illness recovery.
Q
Is this calculator suitable for athletes?BMI is less accurate for athletes with high muscle mass -- such individuals often show overweight or obese BMI despite low body fat. Similarly, IBW formulas do not account for muscle. Athletes should use body fat percentage measurement alongside these tools for a more accurate picture.
Q
How accurate are ideal weight formulas?The four formulas typically agree within 3 -- 5 kg for average-height adults. At extreme heights (under 152 cm / 5 ft or over 193 cm / 6 ft 4 in), they diverge more noticeably. All were developed from population data and represent statistical averages, not individually calibrated targets.
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