Ideal Weight Calculator
The Ideal Weight Calculator estimates healthy weight ranges using several trusted medical formulas, including Devine, Robinson, Miller, and Hamwi. These formulas provide evidence-based ideal body weight (IBW) estimates using your height, sex, and optional frame size. The calculator also provides a BMI-based healthy weight range, helping you understand where you fall relative to recommended guidelines. All results update instantly as you enter your details and remain completely private since every calculation happens in your browser. Whether you're tracking fitness progress, planning a nutrition strategy, or simply curious about healthy weight guidelines, this ideal weight calculator gives you accurate, fast, and easy-to-understand results from multiple scientific methods.
What Is an Ideal Weight Calculator?
An ideal weight calculator estimates a target body weight based on height, sex, and frame size using validated clinical formulas. Unlike BMI, which uses the same weight range for everyone of the same height regardless of build, ideal body weight (IBW) formulas were developed for specific applications — the Devine formula was originally created for drug dosing calculations in 1974 and remains the most widely used clinically. These formulas provide a reference range, not a prescriptive target: athletes, highly muscular individuals, and those with large bone structure often fall above IBW estimates without any health concern.
Ideal Body Weight Formula Comparison
| Formula | Year | IBW at 5'6" (Female) | Best For |
|---|---|---|---|
| Devine | 1974 | 130 lbs | Clinical drug dosing (most used medically) |
| Robinson | 1983 | 127 lbs | General population; slightly lower estimates |
| Miller | 1983 | 135 lbs | Metabolic research; higher estimates |
| Hamwi | 1964 | 130 lbs | Dietetics; simple, widely taught |
Use the overlap range across formulas (127–135 lbs for a 5'6" female) as your reference. Athletes and those with higher muscle mass may be healthiest above these estimates.
Ideal Weight by Height Reference Table (Devine Formula)
| Height | Female IBW | Male IBW | BMI Healthy Range |
|---|---|---|---|
| 5'0" (152 cm) | 108 lbs | 123 lbs | 95–128 lbs |
| 5'4" (163 cm) | 120 lbs | 137 lbs | 108–145 lbs |
| 5'6" (168 cm) | 130 lbs | 148 lbs | 118–155 lbs |
| 5'8" (173 cm) | 140 lbs | 159 lbs | 125–168 lbs |
| 5'10" (178 cm) | 150 lbs | 170 lbs | 132–178 lbs |
| 6'0" (183 cm) | 160 lbs | 181 lbs | 140–188 lbs |
Frame size adjustment: Small frame −10%, Large frame +10%. Measured by wrist circumference: Women <5.5" small, 5.5–6.5" medium, >6.5" large.
Worked Example: Lisa at 5'6"
5'6" female, medium frame | Devine: 130 lbs | Robinson: 127 lbs | Miller: 135 lbs | Hamwi: 130 lbs
Formula range: 127–135 lbs | BMI healthy range: 118–155 lbs
Best target: 127–135 lbs (formula consensus)
If Lisa is muscular or large-framed, 135–145 lbs may be equally healthy
IBW vs. BMI: Which Should You Use?
IBW formulas (Devine, Robinson, Miller, Hamwi) express ideal weight as a single number or small range based on height. BMI expresses a range (18.5–24.9) that produces a wider weight window. For a 5'6" woman, the Devine formula gives 130 lbs (one target) while BMI gives 118–155 lbs (a 37 lb range). In clinical settings, IBW is preferred for drug dosing and nutritional support calculations because single-value estimates are more practical. For general health guidance, the BMI healthy range is more realistic since it accommodates different body builds. Use both: if you’re within the BMI range and near the IBW formula consensus, you’re at a genuinely healthy weight.
Frequently Asked Questions About Ideal Weight
Which ideal weight formula is most accurate?
No single formula is universally "most accurate" because they were derived from different populations for different purposes. Devine (1974) is the most widely used in clinical settings for drug dosing. Robinson (1983) tends to give slightly lower, more conservative estimates. For general health guidance, the average across all four formulas is a reasonable target, adjusted ±10% for frame size.
What if I'm above my ideal body weight?
IBW formulas provide a reference point, not a health verdict. Many people are healthy well above their calculated IBW, particularly if they have high muscle mass or large bone structure. Focus on body composition (body fat %) and metabolic markers (blood pressure, blood glucose, cholesterol) rather than hitting a specific number from a formula designed decades ago.
Does ideal weight differ by age?
The original formulas don't adjust for age, but research suggests optimal BMI shifts slightly with age. Adults over 65 with BMI 25–27 often have better health outcomes than those in the 22–24 range, possibly due to fat reserves helping survival during illness. Some clinicians use age-adjusted targets for older adults.
How does frame size affect ideal weight?
Frame size — measured by wrist circumference — adjusts IBW by ±10%. A small-framed 5'6" woman might target 117–127 lbs; a large-framed woman might target 130–145 lbs. Frame size reflects bone density and skeletal mass, which contributes to healthy weight independently of fat and muscle mass.
Can athletes use ideal weight calculators?
Athletes should use IBW as a rough reference only. A 5'10" male with 190 lbs and 12% body fat is well above his Devine IBW of 170 lbs but is objectively healthier than someone at 170 lbs with 28% body fat. For athletes, body fat percentage and performance metrics are far more meaningful than IBW formula outputs.
What is the Hamwi formula?
The Hamwi formula (1964) is one of the simplest IBW calculations: Men = 106 lbs for first 5 feet + 6 lbs per inch above 5 feet; Women = 100 lbs for first 5 feet + 5 lbs per inch above 5 feet. For a 5'6" woman: 100 + (5 × 6) = 130 lbs. It's widely taught in nutrition and dietetics because it's easy to calculate mentally.