Health Calculator
Reverse BMI Calculator
Work backward from your goal BMI. Find the target weight for your height, the target height for your weight, or view the healthy weight range at your stature—with metric and imperial units, category labels, and optional comparison to where you are today. This powerful reverse BMI calculator helps you set realistic weight loss goals, plan healthy weight gain, understand ideal body weight ranges, and track your progress toward a healthier BMI. Whether you're calculating target weight for weight management, exploring healthy BMI ranges for your height, or understanding the relationship between height and weight, this tool provides accurate calculations with instant results.
Reverse BMI Calculator
Find target weight or height for a goal BMI
Quick examples
Common healthy target: 18.5–24.9
Optional — compare to current weight
Results
Enter your target BMI and measurements, then click Calculate
How Reverse BMI Works
Standard BMI is weight ÷ height². A reverse BMI calculator algebraically solves that equation for the missing variable: either weight or height, given your target BMI. Instead of calculating what your BMI is based on current measurements, you start with a desired BMI and work backward to find what weight or height would achieve that target.
This is useful for setting realistic goals, understanding how much weight change corresponds to a healthier BMI band, or exploring how height and weight interact on the BMI scale. For weight management, you can calculate exactly how many pounds or kilograms you need to lose or gain to reach a healthy BMI range. Fitness enthusiasts and healthcare providers use reverse BMI calculations to set achievable targets, create personalized weight loss plans, and educate patients about healthy weight ranges.
The calculator supports both metric (kilograms, centimeters, meters) and imperial (pounds, feet, inches) units, making it accessible for users worldwide. By entering your height and target BMI, you instantly see your goal weight in both units, along with BMI category classification and the healthy weight range for your specific height.
Formulas
Target Weight (kg) = Target BMI × Height(m)²
Target Height (m) = √(Weight(kg) / Target BMI)
Target Weight (lbs) = kg × 2.20462
Healthy range: BMI 18.5–24.9 at your height
Benefits of Using a Reverse BMI Calculator
A reverse BMI calculator offers several advantages for anyone interested in weight management, fitness planning, or understanding healthy body metrics. By working backward from a target BMI, you gain clarity on exactly what weight or height corresponds to your health goals, eliminating guesswork from your fitness journey.
Set Realistic Weight Loss Goals: Instead of arbitrarily choosing a target weight, calculate the precise weight needed to achieve a healthy BMI range. This data-driven approach helps you set achievable, medically-grounded goals based on your height and body structure.
Plan Healthy Weight Gain: For underweight individuals or athletes looking to add mass, reverse BMI calculations show exactly how much weight gain is needed to reach a healthy BMI category, preventing excessive or insufficient weight changes.
Understand Healthy Weight Ranges: By calculating the weight range for BMI 18.5-24.9 at your specific height, you learn your personalized healthy weight zone. This range varies significantly based on stature, making individualized calculations essential.
Track Progress Effectively: The comparison feature lets you see your current BMI versus your target BMI, quantifying exactly how much weight change is needed. This makes tracking weight loss or gain progress more meaningful and motivating.
Educational Value: Healthcare professionals, fitness trainers, and educators use reverse BMI tools to teach patients and clients about the relationship between height, weight, and BMI, promoting better health literacy.
Calculation Modes
- Target weight: Enter height and goal BMI to get kg, lbs, and healthy range. Perfect for weight loss planning and setting fitness goals based on your desired BMI.
- Target height: Enter weight and goal BMI to get cm and feet/inches. Useful for educational purposes and understanding how height affects BMI classification.
- Comparison: Optional current values show BMI today and change needed. Track your weight management progress by comparing current BMI to your target BMI.
- Categories: Underweight, Normal, Overweight, or Obese for your target BMI. Instant BMI category classification helps you understand health implications of your goals.
When to Use This Calculator
Use the reverse BMI calculator whenever you need to understand the relationship between BMI, height, and weight from a goal-oriented perspective. This tool is particularly valuable in several scenarios related to health, fitness, and medical planning.
Weight Loss Planning: Before starting a diet or exercise program, calculate your target weight for a healthy BMI range. This gives you a concrete, medically-supported goal rather than an arbitrary number. Knowing exactly how many pounds or kilograms to lose helps create realistic timelines and measurable milestones.
Weight Gain for Underweight Individuals: If you're underweight and working to reach a healthy weight, reverse BMI calculations show precisely how much weight gain is needed to enter the normal BMI range. This prevents excessive weight gain and ensures your goals align with health recommendations.
Fitness and Athletic Training: Athletes and fitness enthusiasts use reverse BMI to set performance goals while maintaining healthy body composition. Bodybuilders, for example, might calculate target weights for different BMI ranges during bulking and cutting phases.
Medical Consultations: Healthcare providers use reverse BMI calculations to educate patients about healthy weight ranges and set realistic treatment goals. The visual comparison between current and target BMI helps patients understand their health status and motivation for change.
Pregnancy and Postpartum Planning: Women planning pregnancy or recovering postpartum can use reverse BMI to understand healthy weight targets before conception and after delivery, supporting maternal and fetal health.
Example Calculations
Example 1 — Target Weight
Target BMI 22.5 · Height 170 cm (5'7")
Target weight = 22.5 × (1.70)² = 65.0 kg
Imperial: 143.3 lbs
Category: Normal
Healthy range at this height: 50.4–71.9 kg (111–158.5 lbs)
Example 2 — Target Height
Target BMI 25 · Weight 80 kg (176.4 lbs)
Target height = √(80 / 25) = 1.789 m
178.9 cm (about 5'10.4")
Category: Overweight threshold
At BMI 24.9 (normal): 179.5 cm (5'10.7")
Example 3 — Healthy Weight Range
Height 165 cm · BMI 18.5 – 24.9
Min weight = 18.5 × (1.65)² = 50.4 kg (111 lb)
Max weight = 24.9 × (1.65)² = 67.8 kg (149.5 lb)
Optimal BMI 22: 60.0 kg (132.3 lbs)
Example 4 — Weight Loss Goal
Current: 90 kg at 175 cm · Target BMI 23
Current BMI = 90 / (1.75)² = 29.4 (Overweight)
Target weight = 23 × (1.75)² = 70.4 kg
Weight to lose: 19.6 kg (43.2 lbs)
Example 5 — Weight Gain Goal
Current: 55 kg at 180 cm · Target BMI 22
Current BMI = 55 / (1.80)² = 17.0 (Underweight)
Target weight = 22 × (1.80)² = 71.3 kg
Weight to gain: 16.3 kg (35.9 lbs)
Frequently Asked Questions
- What is a reverse BMI calculator?
- Instead of calculating BMI from height and weight, a reverse BMI calculator solves for the weight or height needed to reach a target BMI you choose. This backward calculation helps you set realistic weight loss or weight gain goals based on desired BMI outcomes.
- How do I find my target weight for a goal BMI?
- Select "Find Target Weight," enter your height and desired BMI. The calculator uses: Target weight (kg) = Target BMI × height(m)². This gives you the exact weight needed to achieve your goal BMI at your current height.
- How do I find my target height for a goal BMI?
- Select "Find Target Height," enter your current weight and target BMI. The calculator uses: Target height (m) = √(weight / Target BMI). This mode is useful for understanding how height affects BMI classification.
- What is a healthy BMI range?
- For adults, WHO commonly cites 18.5–24.9 as the normal BMI range. This tool shows the corresponding weight range at your height when calculating target weight, helping you understand healthy weight goals specific to your stature.
- Can I compare to my current weight or height?
- Yes. Optional current weight (in weight mode) or current height (in height mode) shows your present BMI and how much you would need to change. This comparison feature helps track progress toward your BMI goals.
- Is reverse BMI the same as ideal body weight formulas?
- They are related. This calculator uses the standard BMI formula directly, so any target BMI you enter (including 22 or 23) maps to a precise weight or height. Unlike traditional ideal body weight formulas that use fixed multipliers, reverse BMI gives you flexibility to choose any target BMI.
- What BMI should I aim for?
- Most health organizations recommend a BMI between 18.5 and 24.9 for adults. A BMI of 22-23 is often considered optimal for health. However, individual factors like muscle mass, age, and health conditions should be considered. Consult a healthcare provider for personalized advice.
- How accurate is the reverse BMI calculator?
- The reverse BMI calculator uses the standard BMI formula with precise mathematical operations. However, BMI itself has limitations—it doesn't account for muscle mass, bone density, age, or gender distribution. Use it as a general guide alongside other health metrics.
- Can I use this calculator for weight loss planning?
- Absolutely. By entering your height and a target healthy BMI (such as 22), you can calculate your goal weight. The comparison feature shows how much weight you need to lose or gain to reach that target, making it valuable for weight management planning.
- Does this calculator work for children and teens?
- This calculator uses the standard adult BMI formula. For children and teenagers (under 20), BMI percentiles specific to age and gender are more appropriate. Pediatric BMI calculations differ from adult calculations and should use age-specific growth charts.
- What are the BMI category classifications?
- Standard BMI categories are: Underweight (BMI below 18.5), Normal weight (BMI 18.5-24.9), Overweight (BMI 25-29.9), and Obese (BMI 30 and above). This calculator automatically categorizes your target BMI to help you understand health implications.
- Why would I need to calculate target height from BMI?
- Calculating target height from BMI is useful for educational purposes, understanding the BMI formula, or exploring how height affects weight classification. It's also helpful for healthcare professionals explaining BMI concepts to patients.