Ideal Weight Calculator
See your ideal body weight from four medical formulas and the healthy BMI range.
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📘 What is the Ideal Weight Calculator?
Ideal weight calculators give you a target range rather than a single number, because "ideal" genuinely depends on which formula you use, your frame size, and your fitness level. This calculator runs your height through four established medical formulas side by side, so you see the actual range clinicians have used historically rather than one arbitrary figure.
⚙️ How Ideal Weight is calculated
Why four different formulas
The Robinson, Miller, Devine, and Hamwi formulas were each developed in different decades (1950s–1980s) for different clinical purposes, mostly medication dosing. They agree broadly but not exactly, which is itself useful information — if all four cluster closely, that range is a more reliable target than any single formula in isolation.
The Devine formula and why it still matters
Devine's 1974 formula, originally created to standardise drug dosing calculations, remains the most widely cited "ideal body weight" formula in clinical literature today. It uses a base weight (50kg for men, 45.5kg for women) plus 2.3kg for every inch over 5 feet.
BMI range as a cross-check
Alongside the four named formulas, this calculator also shows the weight range corresponding to a BMI of 18.5–24.9 for your height — a useful sanity check since BMI is the most commonly referenced standard, even though it has its own well-documented limitations for muscular or very tall individuals.
Robinson formula (1983)
Ideal weight (kg) = 52 + 1.9 × (height in inches − 60) [men]
Women: 49 + 1.7 × (height in inches − 60)
🧮 Worked examples
Example — 175cm male
A man who is 175 cm tall (about 5 ft 9 in).
→ Robinson formula gives an ideal weight of approximately 68.9 kg
Example — BMI range cross-check
Same person, using the BMI 18.5–24.9 normal range instead.
→ Healthy weight range ≈ 56.7 kg to 76.2 kg — a wider band than any single formula alone
💡 Original insights & how to use this calculator
Why your "ideal" weight is a range, not one number
No single formula is correct for everyone — frame size, muscle mass, and ethnicity all shift where a genuinely healthy weight sits for a given height. Use the spread across all four formulas as your real target range, not the single narrowest number.
Setting a realistic weight goal
If your current weight is meaningfully above every formula's estimate, treat the highest of the four estimates as a more achievable first milestone rather than the lowest — psychologically, hitting an early milestone matters more than chasing the most aggressive number first.
When to ignore this calculator entirely
Athletes, bodybuilders, and anyone with significant muscle mass should weight body fat percentage far more heavily than any ideal-weight formula, since none of these formulas can distinguish muscle from fat.
💡 Expert Tips
No formula fits everyone — use as a guide.
The BMI range 18.5–24.9 is most widely accepted.
How to read your result
The four formulas here (Robinson, Miller, Devine, Hamwi) were each derived from different population samples decades ago and can disagree by 3-5kg for the same height — that spread is normal, not a sign one is wrong. Treat the range across all four as your target zone, not any single number as gospel, and remember these ignore frame size and muscle mass entirely.
⚠️ Common Mistakes
✕ Picking the single lowest formula result as 'the' target weight.
✓ Use the spread across all four formulas as a healthy range, not a single target — someone with a larger frame or more muscle mass reasonably sits at the higher end.
✕ Treating 'ideal weight' as more scientifically precise than BMI.
✓ These formulas are actually older and less validated than BMI in modern research — useful as a second opinion, not a replacement for discussing a healthy target with a doctor.
Frequently Asked
Which formula is best?▾
The BMI-based healthy range is most widely used. Each formula was derived from different populations.
🔎 Explore related calculators
BMI Calculator
Example 1 — Metric
BMI = 70 ÷ (1.75 × 1.75) = 70 ÷ 3.0625 ≈ 22.9 — Normal weight