Use this professional calculator to determine your exact target weight based on Body Mass Index (BMI). Ideal for health planning and fitness tracking.
Calculate Weight from BMI
Enter your height and target BMI to find the corresponding weight.
Metric (cm, kg)
Imperial (ft/in, lbs)
Enter height in centimeters.
Please enter a valid height (50-300).
Enter height in feet and inches.
Please enter a valid height.
Standard Normal BMI range is 18.5 – 24.9.
Please enter a realistic BMI (10-60).
Calculated Target Weight
—
Based on Height: — and BMI: —
Min Healthy Weight (BMI 18.5)
—
Max Healthy Weight (BMI 24.9)
—
Healthy Range Span
—
Visual representation of weight ranges for your height
Reference weight boundaries for your specific height.
BMI Category
BMI Range
Calculated Weight Range
Comprehensive Guide: How to Calculate Weight from BMI
Understanding the relationship between body mass and height is fundamental to health planning. Whether you are setting fitness goals, working with a healthcare provider, or simply curious about body metrics, the ability to calculate weight from BMI provides a precise, data-driven target. This guide explores the mathematics, practical applications, and limitations of reversing the BMI formula.
To calculate weight from BMI is the process of using a known or desired Body Mass Index (BMI) score along with your fixed height to determine the corresponding body weight. While standard BMI calculators take weight and height to output a score, this "reverse" calculation is essential for goal setting.
This approach is widely used by:
Athletes determining weight classes.
Medical patients establishing recovery weight goals.
Fitness enthusiasts visualizing what a "22 BMI" looks like on the scale.
It is important to note that while this calculation gives a precise number, it does not distinguish between muscle mass and fat mass. It is purely a metric of mass relative to height.
Calculate Weight from BMI: Formula and Explanation
The math required to calculate weight from BMI is a direct algebraic rearrangement of the standard BMI equation. The formula differs slightly depending on whether you use the metric or imperial system.
Metric Formula
Weight (kg) = BMI × (Height in meters)²
Imperial Formula
Weight (lbs) = (BMI × (Height in inches)²) ÷ 703
Variable Definitions
Variable
Meaning
Unit (Metric/Imperial)
Typical Range
BMI
Body Mass Index
Score (unitless)
18.5 – 24.9 (Healthy)
Height
Vertical Stature
Meters / Inches
1.5m – 2.0m / 59″ – 79″
Constant
Conversion Factor
None / 703
Fixed
Understanding the inputs helps you accurately calculate weight from bmi.
Practical Examples (Real-World Use Cases)
Let's look at two detailed scenarios to understand how to calculate weight from bmi in real life.
Example 1: The Health Goal (Imperial)
Scenario: John is 5 feet 10 inches tall (70 inches). He has been advised by his doctor to reach a "middle-normal" BMI of 22. He wants to know exactly what number he needs to see on the scale.
Calculation:
Height: 70 inches
Target BMI: 22
Formula: (22 × 70²) ÷ 703
Step 1: 70² = 4,900
Step 2: 22 × 4,900 = 107,800
Step 3: 107,800 ÷ 703 ≈ 153.3 lbs
Result: John needs to reach approximately 153 lbs to achieve a BMI of 22.
Example 2: The Clinical Threshold (Metric)
Scenario: Maria is 1.65 meters tall. She wants to know the maximum weight she can be before crossing into the "Overweight" category (BMI 25).
Calculation:
Height: 1.65 m
Target BMI: 25
Formula: 25 × 1.65²
Step 1: 1.65 × 1.65 = 2.7225
Step 2: 25 × 2.7225 ≈ 68.1 kg
Result: If Maria exceeds 68.1 kg, her BMI will indicate she is overweight.
How to Use This Calculate Weight from BMI Tool
Select System: Choose between Imperial (lbs/ft) or Metric (kg/cm) at the top of the tool.
Input Height: Enter your accurate height. Small errors in height are squared in the formula, leading to larger errors in the weight result.
Enter Target BMI: Input your desired BMI. Use the defaults (22 is mid-normal) or consult a health chart.
Analyze Results: The tool will instantly calculate weight from bmi. Check the "Intermediate Values" to see the full healthy weight range for your height.
Key Factors That Affect BMI Results
When you calculate weight from bmi, you are dealing with a raw mathematical abstraction. Several real-world factors influence how this number relates to actual health.
Muscle Mass Density: Muscle is denser than fat. An athlete might calculate a weight for a BMI of 25 (borderline overweight) but actually have a very low body fat percentage.
Bone Structure: Individuals with larger frame sizes naturally weigh more. The formula to calculate weight from bmi does not account for wrist or ankle circumference.
Age and Metabolism: As we age, muscle mass tends to decrease and bone density changes. A senior citizen might need a slightly different target BMI for optimal health compared to a young adult.
Hydration Levels: Your weight fluctuates daily based on water retention. The calculated target is a static goal, but your daily weight is dynamic.
Gender Differences: Men generally have more lean mass than women. While the BMI calculation is unisex, the healthy composition of that weight differs by gender.
Pregnancy: This calculator and the BMI scale are not applicable during pregnancy or immediate postpartum periods.
Frequently Asked Questions (FAQ)
1. Is it accurate to calculate weight from BMI for bodybuilders?
No. Bodybuilders have high muscle mass which skews BMI. A bodybuilder might calculate a "healthy" weight that requires them to lose essential muscle. Body fat percentage is a better metric for athletes.
2. What is the ideal BMI to use for the calculation?
For most adults, a BMI between 18.5 and 24.9 is considered healthy. A BMI of 22 is often used as a median "ideal" target when you calculate weight from bmi.
3. Does this calculator work for children?
No. Children and teens use BMI percentiles based on age and growth charts. Do not use this standard adult formula for anyone under 18.
4. How often should I check my BMI?
Since height rarely changes for adults, you only need to check your weight periodically. Recalculating your target is only necessary if your health goals change.
5. Can I use this to determine weight loss goals?
Yes. By inputting a lower BMI (e.g., 24) than your current one, you can determine exactly how many pounds or kilograms you need to reach to enter a healthier category.
6. Why does the chart show a range?
Health is not a single number. The "Normal" category spans several BMI points. The chart visualizes this bandwidth to give you a flexible target rather than a rigid number.
7. Does height measurement affect the result significantly?
Yes. Because height is squared in the formula, a 1-inch error can shift the calculated weight result by several pounds. Always measure height without shoes.
8. Are there racial differences in BMI risks?
Yes. Some studies suggest that health risks associated with BMI may trigger at lower points for Asian populations and potentially higher points for others. Consult a doctor for personalized advice.
Related Tools and Internal Resources
Enhance your health planning with our suite of related calculators: