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Free Ideal Weight Calculator – Find Your Target Weight
Estimate your ideal body weight using multiple evidence-based formulas. Compare Devine, Robinson, Miller, and Hamwi results side by side.
Quick answer
For a 175 cm (5'9") male, ideal weight estimates range from 66 to 76 kg (145–168 lb) depending on the formula used. These formulas provide rough guidelines — your true ideal weight depends on your body composition, muscle mass, and individual health markers.
What This Calculator Does
The PrimeMacros ideal weight calculator estimates a target body weight using four well-known clinical formulas: Devine (1974), Robinson (1983), Miller (1983), and Hamwi (1964). Each formula takes height and sex as inputs and produces a different estimate, reflecting the fact that there is no single "ideal" weight for a given height. The range across formulas gives you a practical target zone rather than a false-precision single number.
Ideal body weight formulas were originally developed for clinical purposes like drug dosing and ventilator settings, not for nutrition or fitness goals. They remain useful as reference points but should be interpreted alongside body composition data, health markers, and personal context.
The Four Formulas Compared
The Devine formula (1974) is the most widely used: for men, IBW = 50 + 2.3 × (height in inches − 60); for women, IBW = 45.5 + 2.3 × (height in inches − 60). The Robinson formula (1983) adjusts slightly: men = 52 + 1.9 × (height − 60 in); women = 49 + 1.7 × (height − 60 in). Miller (1983) produces lower estimates: men = 56.2 + 1.41 × (height − 60 in); women = 53.1 + 1.36 × (height − 60 in). Hamwi (1964) uses: men = 48 + 2.7 × (height − 60 in); women = 45.5 + 2.2 × (height − 60 in).
For a 175 cm (69 inches, or 5'9") male, the results are: Devine 70.8 kg, Robinson 68.9 kg, Miller 68.9 kg, and Hamwi 72.3 kg. This gives a range of about 69–72 kg. For a 165 cm (65 inches, or 5'5") female: Devine 57.0 kg, Robinson 57.5 kg, Miller 59.9 kg, and Hamwi 56.5 kg, yielding a range of about 56–60 kg.
None of these formulas account for muscle mass, frame size, or body fat percentage. A person with significant muscle mass may be healthy at a weight well above the formula estimate. Conversely, someone with low muscle mass might need to be at or below the estimate to have a healthy body fat percentage.
Frame Size and Individual Variation
Some older guidelines adjust ideal weight by frame size — small, medium, or large — based on wrist circumference or elbow breadth. While this adds some nuance, it still does not account for muscle mass. A more modern approach is to aim for a body fat percentage within the healthy range (14–24% for men, 21–35% for women) and use the corresponding weight as your personal target.
Genetic factors, bone density, and training history all influence what weight is healthiest for a given individual. A powerlifter and a distance runner of the same height will have very different ideal weights. Use formula estimates as orientation, not as prescriptive targets.
Setting a Realistic Goal Weight
If you are above the formula range, do not try to reach the exact number immediately. Research shows that losing even 5–10% of body weight produces meaningful health improvements in blood pressure, blood sugar, and cholesterol. Set intermediate goals and reassess as you reach them.
If you are below the formula range and not intentionally lean for a sport, consider whether insufficient calorie intake or low muscle mass may be a factor. Underweight carries health risks including weakened immunity, bone density loss, and hormonal disruption. A gradual increase in calories with resistance training can help build toward a healthier weight.
Ideal weight estimates by formula (175 cm / 5'9" male)
| Formula | Year | Estimated Ideal Weight |
|---|---|---|
| Devine | 1974 | 70.8 kg (156 lb) |
| Robinson | 1983 | 68.9 kg (152 lb) |
| Miller | 1983 | 68.9 kg (152 lb) |
| Hamwi | 1964 | 72.3 kg (159 lb) |
| Average of Four | — | 70.2 kg (155 lb) |
Frequently asked questions
Which ideal weight formula is the most accurate?
No single formula is definitively "most accurate" because ideal weight depends on individual factors like muscle mass, frame size, and body composition that these formulas ignore. The Devine formula is most widely used in clinical settings. Using the average of all four provides a reasonable middle ground.
Can my ideal weight be higher than the formula says?
Absolutely. If you have above-average muscle mass from strength training, your healthiest weight will likely exceed formula estimates. Body fat percentage is a better indicator of health than comparing to formula-based ideal weights.
Should I use ideal weight or body fat percentage as a goal?
Body fat percentage is more informative because it accounts for muscle mass. However, not everyone has easy access to body fat measurement. Ideal weight formulas offer a convenient starting reference. For best results, use both metrics and prioritize how you look, feel, and perform.
Do ideal weight formulas work for very tall or short people?
These formulas become less reliable at height extremes. Very tall individuals (above 190 cm) may find estimates too low, while very short individuals (below 155 cm) may find them too high. The BMI normal range (18.5–24.9) may be more appropriate at extreme heights.
How quickly should I try to reach my ideal weight?
A safe rate of weight change is 0.5–1.0% of body weight per week for loss, or 0.25–0.5% for gain. Losing 0.5 kg per week means a 10 kg goal would take about 20 weeks. Patience reduces muscle loss, metabolic adaptation, and rebound risk.
Related resources
Methodology and trust notes
PrimeMacros uses common nutrition planning equations such as Mifflin-St Jeor for BMR/TDEE estimates, body-weight based protein ranges, and explicit health disclaimers. Results are planning estimates, not diagnosis, treatment or individualized nutrition therapy.
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