Ideal Weight Calculator - Healthy Range
Calculate your ideal body weight using Robinson, Miller, Devine, and BMI-based formulas. Accounts for height, age, frame size, and gender for accurate
Medical disclaimer: This calculator is provided for educational and informational purposes only and does not constitute medical advice, diagnosis, or treatment. Results are general estimates and may not reflect your individual circumstances. Always consult a qualified healthcare professional before making decisions about your health.
Formula
IBW = 50 + 2.3 × (height(in) - 60) for men
The Devine formula calculates ideal weight based on height. Different formulas exist, providing a range rather than a single target.
Worked Examples
Example 1: Average Male
Problem:Calculate ideal weight for male, 180cm tall.
Solution:Height in inches = 180cm / 2.54 = 70.9 inches Devine Formula: IBW = 50 + 2.3 × (70.9 - 60) IBW = 50 + 2.3 × 10.9 = 75.1 kg BMI Range (18.5-24.9): Min: 18.5 × (1.80)² = 60.0 kg Max: 24.9 × (1.80)² = 80.6 kg Healthy range: 60-81 kg Formula average: ~75 kg
Result:75 kg ideal, 60-81 kg healthy range
Example 2: Female Example
Problem:Calculate for female, 5'4" (64 inches).
Solution:Height = 64 inches = 162.6 cm Devine Formula: IBW = 45.5 + 2.3 × (64 - 60) IBW = 45.5 + 2.3 × 4 = 54.7 kg = 121 lbs Robinson Formula: IBW = 49 + 1.7 × 4 = 55.8 kg = 123 lbs BMI Range: 18.5 × (1.626)² = 48.9 kg (108 lbs) 24.9 × (1.626)² = 65.8 kg (145 lbs) Healthy range: 108-145 lbs
Result:55 kg (121 lbs) ideal, 109-145 lbs healthy
Example 3: Using for Goal Setting
Problem:Person is 170cm, currently 95kg, wants a target weight.
Solution:Height = 170cm Ideal weight formulas average: ~68 kg BMI healthy range: 53.4-71.8 kg Current: 95 kg Ideal target: 68 kg Difference: 27 kg At 0.5kg/week: 54 weeks At 0.75kg/week: 36 weeks Realistic initial target: 80 kg (in 6 months) Then reassess for final target.
Result:Set intermediate goal of 80 kg first
Frequently Asked Questions
What is ideal body weight?
Ideal body weight (IBW) is an estimated healthy weight based on height and sex. Multiple formulas exist (Devine, Robinson, Miller, Hamwi), each giving slightly different results. These are guidelines, not strict targets. Healthy weight exists within a range, not a single number.
Which ideal weight formula is best?
No single formula is definitively 'best.' Devine is most commonly used in medicine. Robinson and Miller are newer refinements. Hamwi is simpler. For most people, the average of multiple formulas is reasonable. BMI-based ranges (18.5-24.9) provide a healthy weight range rather than a single target.
Why do the formulas give different results?
Each formula was derived from different populations and methods. Devine studied medical dosing, Robinson analyzed insurance data, Miller refined Robinson's work, and Hamwi created rules of thumb for nutrition. The variations are typically 5-10 kg, reflecting that 'ideal' weight is a range, not a precise number.
How is ideal weight used in medicine?
IBW is used for: drug dosing (especially when actual weight is very high or low), ventilator settings, nutritional planning, and as a reference point in clinical assessments. For obesity, adjusted body weight (ABW) may be used rather than actual or ideal weight.
Does ideal weight account for body type?
No. These formulas only use height and sex. They don't account for: bone structure, muscle mass, ethnicity, age, or frame size. A muscular athlete may exceed IBW while being very healthy. Use IBW as one reference point among many health indicators.
Should I aim for my ideal weight?
Not necessarily as an absolute target. Aim for a healthy range based on BMI (18.5-24.9), body composition, how you feel, fitness level, and health markers (blood pressure, cholesterol, blood sugar). Being 5-10 kg above IBW while active and healthy is perfectly fine.
How does age affect ideal weight?
These formulas don't account for age. Some research suggests slightly higher BMI (25-27) may be healthier for those over 65 (the 'obesity paradox'). However, maintaining muscle mass and functional fitness matters more than a specific number as you age.
Can I use ideal weight for goal setting?
Yes, but be flexible. If IBW says 70 kg but you feel great at 75 kg with good fitness and health markers, 75 kg is fine for you. Use IBW as a general guideline, not a rigid target. Focus on sustainable healthy habits rather than a specific number.
What's adjusted body weight for dosing?
For obese patients, some drugs are dosed using Adjusted Body Weight: ABW = IBW + 0.4 × (Actual Weight - IBW). This adjusts for the fact that fat tissue affects drug distribution differently than lean tissue. This is a medical calculation done by healthcare providers.
What is a healthy resting heart rate?
A normal resting heart rate for healthy adults ranges from 60-100 beats per minute (bpm), measured after at least 5 minutes of stillness, ideally first thing in the morning before getting out of bed. Well-trained endurance athletes can have resting rates of 40-60 bpm because their hearts pump a larger volume per beat (higher stroke volume), requiring fewer contractions. A resting HR consistently above 100 bpm (tachycardia) may indicate anemia, hyperthyroidism, dehydration, chronic stress, or cardiovascular strain and warrants medical evaluation. Tracking your resting heart rate over time is a useful fitness marker — a downward trend typically signals improving cardiovascular efficiency as you become more aerobically fit.