What is an ideal weight calculator?
An ideal weight calculator estimates the body weight considered optimal for a given height using established clinical formulas. This calculator compares four formulas — Devine, Hamwi, Robinson, and Miller — alongside the BMI healthy range, a runner's weight target, an abs goal weight, frame size adjustment, and your current weight delta. No other free tool combines all of these in one place.
The formulas were originally developed for clinical drug dosing, not aesthetic goals. Use them as a health reference window — not a rigid target — and adjust for your individual body composition and fitness goals.
The four ideal body weight formulas compared
| Formula | Male (kg) | Female (kg) | Origin / use |
|---|---|---|---|
| Devine (1974) | 50 + 2.3 × in over 5 ft | 45.5 + 2.3 × in over 5 ft | Digoxin dosing — most widely used in medicine |
| Hamwi (1964) | 48 + 2.7 × in over 5 ft | 45.5 + 2.2 × in over 5 ft | Insulin dosing — gives slightly higher values |
| Robinson (1983) | 52 + 1.9 × in over 5 ft | 49 + 1.7 × in over 5 ft | Actuarial insurance data — conservative estimates |
| Miller (1983) | 56.2 + 1.41 × in over 5 ft | 53.1 + 1.36 × in over 5 ft | Insurance data — highest estimates of the four |
Example: 178 cm (5'10") male → Devine: 73 kg | Hamwi: 75 kg | Robinson: 71 kg | Miller: 76.3 kg | Average: 73.8 kg
Body frame size and ideal weight adjustment
People of the same height can have significantly different bone structures. Frame size adjusts the formula average by ±10%: a small-framed person carries less skeletal mass and should weigh closer to the lower end; a large-framed person carries more bone and can support more weight without excess fat.
| Frame | Male wrist | Female wrist | Weight adjustment |
|---|---|---|---|
| Small | < 6.5 in (16.5 cm) | < 5.75 in (14.6 cm) | −10% of average formula |
| Medium | 6.5 – 7.5 in | 5.75 – 6.5 in | Average formula (no adjustment) |
| Large | > 7.5 in (19 cm) | > 6.5 in (16.5 cm) | +10% of average formula |
Enter your wrist circumference above to have frame size detected automatically, or manually select it with the frame toggle.
Ideal running weight calculator
Elite distance runners typically maintain a BMI of 19.5–21.5. Lighter body weight reduces the oxygen cost of moving per unit distance and decreases ground reaction forces on each stride. This calculator uses a target BMI of 20.5 for the running weight estimate — the midpoint of the range where most competitive distance runners operate.
For a 178 cm runner, that equates to approximately 65 kg (143 lbs). Going below BMI 18.5 risks Relative Energy Deficiency in Sport (RED-S) — reduced bone density, hormonal disruption, and increased injury risk. The running weight target is a performance reference, not a minimum.
Ideal weight for visible abs
Abs become consistently visible at approximately 10–12% body fat for men and 16–19% for females. This calculator estimates the weight at which you'd reach those thresholds (using 11% for males, 17% for females) based on your estimated lean mass at the Devine ideal weight.
Note: this is a ballpark. Actual ab visibility depends on where you store fat (genetics), your muscle development, and your current body fat — not just total weight. Use our body fat calculator to measure your current BF% for a more precise projection.
What is adjusted body weight (ABW)?
Adjusted body weight is used in clinical settings when a patient's actual weight significantly exceeds their ideal body weight. Rather than dosing medications based on total body weight (which overestimates distribution volume) or IBW alone (which underestimates), ABW splits the difference:
ABW = IBW + 0.4 × (actual weight − IBW)
The 0.4 factor reflects that approximately 40% of excess weight above IBW is metabolically active lean tissue. This calculator shows ABW whenever your current weight exceeds the Devine IBW.
Limitations of ideal weight formulas
- Muscle mass is ignored: A powerlifter or bodybuilder may weigh 15–20 kg above their 'ideal weight' while carrying less than 10% body fat. These formulas have no way to distinguish muscle from fat.
- Formulas were derived from limited populations: Most were developed from North American and European data in the 1960s–1980s. They may not reflect optimal weights for other ethnicities or modern activity levels.
- Applies only to adults over 5 ft: The formulas don't extrapolate below 60 inches (152 cm) height. For children and teens, use age-specific BMI-for-age percentile charts.
- No account for age: Muscle mass naturally declines with age (sarcopenia). An 'ideal weight' may stay the same but body composition changes significantly — two people at the same weight can have vastly different health profiles at 30 vs 70.
Frequently asked questions
What is the most accurate ideal weight formula?
No single formula is definitively most accurate — each was derived from a different dataset. The Devine formula is the most widely used in clinical medicine. Using the average of all four (Devine, Hamwi, Robinson, Miller) gives a more robust estimate than any single formula.
What is the Devine formula for ideal body weight?
Male IBW = 50 kg + 2.3 kg × (height in inches − 60). Female IBW = 45.5 kg + 2.3 kg × (height in inches − 60). At 5 ft 10 in (178 cm), a male's Devine IBW is 73 kg (161 lbs). The formula applies only to adults over 5 feet tall.
How does frame size affect ideal weight?
Frame size adjusts ideal weight by ±10%. Small-framed individuals carry less skeletal mass; large-framed individuals carry more. Frame size is detected from wrist circumference — for males: < 6.5 in = small, 6.5–7.5 = medium, > 7.5 = large.
What is the ideal weight for runners?
Elite distance runners typically have a BMI of 19.5–21.5. This calculator uses a target BMI of 20.5. For a 178 cm runner that is approximately 65 kg. Going below BMI 18.5 risks RED-S (Relative Energy Deficiency in Sport).
What is adjusted body weight (ABW)?
ABW = IBW + 0.4 × (actual weight − IBW). It is used in clinical settings for medication dosing when actual weight significantly exceeds ideal weight. It accounts for the fact that approximately 40% of excess weight is lean tissue, not fat.
What weight do I need to see my abs?
Abs become visible at approximately 10–12% body fat for men and 16–19% for women. This calculator estimates your abs goal weight at 11% (male) or 17% (female) based on your estimated lean mass. Actual visibility depends on fat distribution and muscle development.
Should I aim for the ideal weight these formulas give?
Use it as a reference range, not a rigid target. A muscular person may weigh 10–15 kg above their formula ideal while having excellent health. Focus on body fat percentage, fitness performance, and metabolic health markers.
Why do the four formulas give different results?
Each was derived for a different clinical purpose from different population datasets: Hamwi (1964) for insulin dosing, Devine (1974) for digoxin dosing, Robinson and Miller (1983) from actuarial insurance data. The ±5–8 kg variation reflects genuine uncertainty — the average of all four is more reliable.
Does ideal weight differ for men and women at the same height?
Yes. All four formulas give lower ideal weights for women than men at the same height, reflecting differences in bone density, muscle mass, and fat distribution. At 170 cm, Devine gives 65.9 kg for males vs 61.4 kg for females.
What is a healthy weight for my height?
A healthy weight range is typically BMI 18.5–25.0 for adults. At 178 cm that is 58.6–79.2 kg. The clinical formula average usually falls within or just below this range. Also check waist circumference (< 94 cm for men, < 80 cm for women) as an independent metabolic risk marker.