Ideal Body Weight Calculator
Find your ideal weight for your height using four classic clinical formulas—Devine, Robinson, Miller, and Hamwi. See the average, ideal weight range, optional frame-size adjustment, current-weight comparison, and PDF export in metric or imperial units.
Enter your details — results appear below after you calculate.
User information
Adds age-specific notes—formulas use height and sex only
Compare against ideal range and see gain/loss estimate
How this Ideal Body Weight calculator works
Select your sex and enter height in metric (cm) or imperial (feet/inches). Optionally add age for under-18 and older-adult screening notes, body frame size (small −10%, medium, large +10%), and your current weight for comparison. We apply four classic clinical formulas— Devine (1974), Robinson (1983), Miller (1983), and Hamwi (1964)—each using inches over 5 feet (height in inches − 60) with sex-specific base weights, then show every result, the average, and an ideal weight range (lowest to highest formula value).
Formula pattern: IBW = base kg + (per-inch slope) × (in − 60). Example (Devine, men): 50.0 + 2.3 × inches over 5 ft. Frame adjustment multiplies each result (×0.9 small, ×1.1 large) before averaging. If you enter current weight, we label you below, within, or above the band and estimate kg/lb to gain or lose to reach the range bounds.
Your report includes a formula breakdown table (all four + average), ideal range hero, current-weight status, weight adjustment guidance, screening insights, interpretation, recommendations, and PDF export. Ideal weight was designed for clinical dosing and nutrition—not as a social “perfect weight.” Muscular, older, pregnant, and pediatric populations need additional context.
For follow-up, try our Body Mass Index (BMI), Calorie Deficit, Waist-to-Height Ratio, and TDEE calculators for screening, safe weight loss, and healthy gain planning.
Ideal Body Weight Calculator – Devine, Robinson, Miller & Hamwi Formulas
Every month, millions search “ideal weight calculator”, “ideal weight for my height”, or “what should I weigh?”—looking for a single number that feels fair, healthy, and achievable. Unlike BMI (weight ÷ height²), classic ideal body weight (IBW) formulas were built for clinical practice: drug dosing, ventilator tidal volumes, nutrition support, and dialysis planning. Our free Ideal Body Weight Calculator runs four widely cited equations—Devine, Robinson, Miller, and Hamwi—shows each result individually, computes the average, and displays an ideal weight range (min–max across formulas). Optionally adjust for body frame size and compare your current weight to see status and gain/loss guidance—with interpretation, recommendations, and PDF export.
All formulas share one structure: a base kilogram value plus a per-inch increment for every inch above five feet (60 inches). Pair results with our Body Mass Index (BMI) Calculator, Calorie Deficit Calculator, and Total Daily Energy Expenditure (TDEE) Calculator for screening, safe weight loss, and healthy gain planning.
What Is Ideal Body Weight?
Ideal body weight (IBW) estimates a weight associated with a given height and sex. The term sounds personal, but in medicine it is a population regression—not a beauty standard or a guarantee of optimal health. Pharmacists use IBW to scale antibiotic and chemotherapy doses; intensivists use it for ventilator settings; dietitians reference it when estimating protein and calorie needs in hospital care.
Because IBW formulas use only height and sex, they are fast and repeatable—but they cannot distinguish muscle from fat, account for age-related muscle loss, or reflect ethnic differences in body composition. That is why waist measures, BMI, body fat percentage, blood pressure, and glucose still matter for a complete picture. Use ideal weight as a screening band, not a verdict.
1What You Enter
Required inputs
- Sex: male or female (each formula is sex-specific)
- Height: metric (cm) or imperial (feet and inches, standing without shoes)
- Unit toggle: metric (kg) or imperial (lb) for display
Optional inputs & tips
- Age (years)—optional; triggers under-18 and 65+ contextual notes
- Body frame size: small (−10%), medium (no change), large (+10%)
- Current weight (kg or lb) for below/within/above comparison
- Measure height at the same time of day for consistency
- Weigh in light clothing, same scale, similar hydration state
- Recalculate after major height changes (adolescents) or significant weight shifts
2Formulas We Use
Let in = total height in inches, and (in − 60) = inches over 5 feet. We convert your height internally, compute each formula in kilograms, apply optional frame adjustment (×0.9, ×1.0, or ×1.1), then display in kg or lb.
Devine formula (1974)
Men: IBW = 50.0 + 2.3 × (in − 60) kg
Women: IBW = 45.5 + 2.3 × (in − 60) kg
Originally published for gentamicin dosing; still one of the most cited IBW equations in pharmacy references.
Robinson formula (1983)
Men: IBW = 52.0 + 1.9 × (in − 60) kg
Women: IBW = 49.0 + 1.7 × (in − 60) kg
A modification of Devine; tends to produce slightly lower estimates for taller men than Devine.
Miller formula (1983)
Men: IBW = 56.2 + 1.41 × (in − 60) kg
Women: IBW = 53.1 + 1.36 × (in − 60) kg
Often yields the highest estimates among the four for many heights—useful context when comparing formula spread.
Hamwi formula (1964)
Men: IBW = 48.0 + 2.7 × (in − 60) kg
Women: IBW = 45.5 + 2.2 × (in − 60) kg
One of the oldest quick-reference rules; common in dietetics textbooks and clinical nutrition courses.
Average, range & frame adjustment
Average = (Devine + Robinson + Miller + Hamwi) ÷ 4
Range min = lowest of four · Range max = highest of four
Frame: small ×0.9 · medium ×1.0 · large ×1.1 applied to each formula result before averaging and ranging.
3What Your Results Include
- Ideal weight range – Min–max across all four formulas (after frame adjustment)
- Average ideal weight – Mean of Devine, Robinson, Miller, and Hamwi
- Formula breakdown – Individual result per equation
- Current weight status – Below, within, or above range (when weight entered)
- Weight adjustment – Estimated kg/lb to gain or lose to reach the band
- Screening insights – Frame note, formula context, limitations
- Interpretation & recommendations – Personalized educational guidance
- PDF export and share – For doctor, dietitian, or trainer visits
4Body Frame Size Adjustment
Two people of the same height and sex can have different bone breadth—wrist, elbow, or shoulder width. A small frame often correlates with narrower wrists; a large frame with broader structure. We scale formula outputs by ±10% when you select small or large frame. If unsure, use medium (no adjustment).
Quick frame-size checks (educational)
| Method | Small frame | Large frame |
|---|---|---|
| Wrist (women, height under 5'2") | < 5.5 in | > 6.25 in |
| Wrist (men, height over 5'5") | < 6.5 in | > 7.5 in |
| Elbow breadth (visual) | Fingers overlap around opposite elbow | Fingers do not touch around elbow |
These are traditional screening heuristics—not diagnostic tests. When in doubt, select medium frame.
5Current Weight Status & Adjustment
When you enter current weight, we compare it to the formula-based ideal range (lowest to highest of the four adjusted values):
- Below range – Current weight is under the lowest formula result; we estimate kg/lb to gain to reach the lower bound.
- Within range – Current weight falls between min and max; no formula-based adjustment suggested.
- Above range – Current weight exceeds the highest formula result; we estimate kg/lb to lose to reach the upper bound.
Sustainable change usually means gradual shifts—often 0.25–0.5 kg (0.5–1 lb) per week for loss, or slow surplus for gain—with adequate protein, resistance training, sleep, and medical support when BMI or health markers are concerning.
Ideal Weight at Common Heights (Reference Table)
Approximate IBW in kilograms using all four formulas (medium frame, no adjustment). Your calculator applies exact math for your entered height.
| Height | Men (avg) | Men (range) | Women (avg) | Women (range) |
|---|---|---|---|---|
| 5 ft 4 in (163 cm) | ~61 kg | 58–64 kg | ~56 kg | 53–59 kg |
| 5 ft 7 in (170 cm) | ~66 kg | 63–69 kg | ~61 kg | 58–64 kg |
| 5 ft 10 in (178 cm) | ~72 kg | 68–75 kg | ~66 kg | 63–69 kg |
| 6 ft 0 in (183 cm) | ~77 kg | 73–80 kg | ~70 kg | 67–73 kg |
Formula Comparison at a Glance
| Formula | Year | Typical use | Relative estimate |
|---|---|---|---|
| Devine | 1974 | Drug dosing, pharmacy references | Mid-range |
| Robinson | 1983 | Modified Devine; clinical nutrition | Often slightly lower (men) |
| Miller | 1983 | Alternative regression; research comparisons | Often highest of the four |
| Hamwi | 1964 | Dietetics, quick bedside estimate | Variable; common in textbooks |
Sample Ideal Weight Calculations
Example A – Woman, 165 cm
Height 165 cm ≈ 65 in → 5 in over 5 ft. Devine: 45.5 + 2.3×5 = 57.0 kg. Robinson: 49 + 1.7×5 = 57.5 kg. Miller: 53.1 + 1.36×5 = 59.9 kg. Hamwi: 45.5 + 2.2×5 = 56.5 kg. Average ≈ 57.7 kg; range ≈ 56.5–59.9 kg.
Example B – Man, 180 cm
Height 180 cm ≈ 71 in → 11 in over 5 ft. Devine: 50 + 2.3×11 = 75.3 kg. Robinson: 52 + 1.9×11 = 72.9 kg. Miller: 56.2 + 1.41×11 = 71.7 kg. Hamwi: 48 + 2.7×11 = 77.7 kg. Average ≈ 74.4 kg; range ≈ 71.7–77.7 kg.
Example C – Large frame (+10%)
Same man (avg 74.4 kg) with large frame: multiply each formula by 1.1 → average ≈ 81.8 kg, range widens proportionally. Frame adjustment reflects bone breadth, not permission to ignore body fat or metabolic health.
Example D – Current weight comparison
Woman (Example A) currently 68 kg—above range max (~59.9 kg). Status: above ideal range. Adjustment: lose ~8 kg to upper bound (educational). Many clinicians would also review BMI, waist, and labs—not formula ideal alone.
Ideal Weight vs BMI – Side-by-Side
Both are height–weight screening tools. They often agree on direction (under vs over) but can differ by several kilograms for the same person.
| Feature | Ideal weight (IBW) | BMI |
|---|---|---|
| Core math | Linear: base kg + per inch over 5 ft | Quadratic: kg ÷ height(m)² |
| Primary origin | Clinical dosing & nutrition | Population epidemiology (WHO) |
| Output style | Single weight or narrow formula band | Index + BMI 18.5–24.9 weight band |
| Sex handling | Separate male/female constants | Same cutoffs (screening) |
| Best paired with | BMI, waist, body fat % | Ideal weight, WHtR, labs |
Clinical Uses of Ideal Body Weight (Educational)
Understanding why formulas exist helps you use them wisely—not as social media “goal weight” mandates.
- Medication dosing – Many IV drug protocols scale to IBW or adjusted body weight when actual weight exceeds IBW significantly.
- Mechanical ventilation – Tidal volume targets often reference IBW (e.g., 6–8 mL/kg IBW in ARDS protocols).
- Nutrition support – Protein and calorie estimates in hospital settings may start from IBW when obesity would overestimate needs if based on actual weight alone.
- Adjusted body weight (AdjBW) – For obese patients, clinicians sometimes use: AdjBW = IBW + 0.4 × (actual weight − IBW) for dosing—not shown in this consumer calculator but explains IBW’s clinical role.
Benefits of Using This Ideal Body Weight Calculator
- Four formulas at once – See Devine, Robinson, Miller, and Hamwi without manual math.
- Transparent range – Min–max band shows formula disagreement instead of hiding it behind one number.
- Frame-size option – ±10% adjustment for bone structure.
- Current-weight comparison – Below/within/above status and gain/loss estimate.
- Metric or imperial – Match your scale and measuring tape.
- Educational depth – Interpretation, insights, and limitations—not just a number.
- Holistic follow-up – Links to BMI, calorie deficit, TDEE, body fat, and waist tools on this site.
How to Use This Ideal Body Weight Calculator
- Choose units – Metric (cm, kg) or imperial (ft/in, lb).
- Select sex – Formulas use different constants for men and women.
- Measure height accurately – Standing straight, heels together, without shoes.
- Pick frame size – Use medium if unsure; adjust after wrist or elbow checks if desired.
- Add current weight (optional) – Enables status and adjustment estimate.
- Calculate – Review range, average, formula table, interpretation, and recommendations.
- Export or share – Save PDF for clinical or coaching visits.
- Follow up – Cross-check with BMI and waist; see a clinician if weight change is unintended or health markers are abnormal.
Weight Management Strategies (Overview)
Below ideal range
- Gradual calorie increase with nutrient-dense foods
- Protein 1.2–1.6 g/kg if gaining lean mass
- Resistance training 2–3×/week
- Rule out hyperthyroidism, GI disease, or eating disorders if unintended
- Use our TDEE Calculator with muscle-gain goal
Within ideal range
- Maintain balanced nutrition and regular activity
- Monitor waist trend and strength, not only scale
- Recalculate if height or training changes significantly
- Athletes may still exceed range with low body fat—context matters
Above ideal range
- Target 5–10% loss first when clinically appropriate
- Use Calorie Deficit Calculator for daily targets
- Prioritize protein, fiber, steps, and sleep (7–9 h)
- Screen BP, glucose, lipids with your clinician
- Avoid crash diets—sustainability beats speed
Understanding Your Result Status
Below ideal range
Current weight under the lowest formula value. May be fine for lean athletes—or signal inadequate intake if unintended. Seek evaluation for unexplained loss.
Within ideal range
Weight falls between min and max across formulas. Maintain habits; still check waist, fitness, and labs.
Above ideal range
Weight exceeds the highest formula value. Modest sustainable changes often improve markers—pair with BMI and clinical guidance.
When Ideal Weight May Mislead
- Athletes & bodybuilders – High lean mass can place you above formula ideal weight with excellent metabolic health.
- Older adults – Sarcopenia (muscle loss) may bring weight into “ideal” range while body fat rises.
- Pregnancy – Obstetric weight-gain charts replace adult IBW.
- Children & teens – Growth charts and percentiles apply—not adult inches-over-5-ft formulas.
- Amputation or limb difference – Standard height-based IBW may need clinical adjustment.
- Edema or fluid retention – Scale weight rises independent of fat mass.
- Very short or very tall stature – Formulas extrapolate beyond populations they were derived from; interpret cautiously.
Common Ideal Weight Mistakes
1. Treating the average as a mandatory target
The average of four formulas is a midpoint—not a rule. The range exists because formulas disagree by design. Staying anywhere in the band can be reasonable depending on composition and health.
2. Ignoring frame size entirely
A large-framed person may be healthy above the unadjusted average; a small-framed person may be healthy below it. Use frame adjustment or interpret range width thoughtfully.
3. Comparing imperial height entered as metric
Entering 170 thinking feet instead of 170 cm produces wildly wrong IBW. Double-check the unit toggle before calculating.
4. Dismissing BMI because ideal weight “feels better”
Neither tool is superior alone. BMI captures curvature of risk with height; IBW reflects clinical dosing tradition. Use both for screening.
5. Crash dieting to hit the lower bound
Rapid loss risks muscle loss, gallstones, and rebound gain. Aim for gradual change with protein, strength training, and professional support when needed.
The Science Behind Ideal Body Weight Formulas
G. J. Hamwi published quick bedside rules in 1964 for diabetes education. B. Devine formalized equations in 1974 for gentamicin pharmacokinetics—cementing IBW in pharmacy. J. D. Robinson and D. R. Miller offered regression refinements in 1983 that remain in nutrition and research comparisons today. None of these authors intended a universal “perfect weight” for wellness marketing—they solved clinical estimation problems with limited variables.
Modern prevention emphasizes waist circumference, body composition, fitness, and cardiometabolic labs alongside height–weight indices. Ideal weight remains useful as a fast reference—especially when you understand its hospital origins and screening limits.
Related Tools on This Site
Build a fuller weight-management picture with our Body Mass Index (BMI) Calculator, Calorie Deficit Calculator, Total Daily Energy Expenditure (TDEE) Calculator, Waist-to-Height Ratio (WHtR), Body Fat Calculator, and Protein Target Calculator.
Frequently Asked Questions (FAQs)
Related Calculators
You might also be interested in these related health and wellness calculators:
Body Fat Percentage Calculator
Calculate your body fat to understand your fitness level and monitor changes over time more accurately than just weighing yourself.
Body Mass Index (BMI) Calculator
Calculate your Body Mass Index (BMI) from height and weight in metric or imperial units. Get WHO categories, healthy weight range, BMI Prime, and PDF export.
Waist-to-Height Ratio (WHtR) Calculator
Calculate waist-to-height ratio (WHtR) from waist and height. Half-height rule, target waist at 0.5, central fat risk bands—often a stronger screen than BMI alone.
Protein Target Calculator
Calculate daily protein targets in grams from body weight, goal, and training—with GLP-1 muscle-preservation (1.6–2.2 g/kg), adjusted weight above 100 kg, sedentary 0.8–1.2 g/kg, and per-meal splits.
Total Daily Energy Expenditure (TDEE) Calculator
Calculate your Total Daily Energy Expenditure (TDEE) and BMR using a validated metabolic formula. Select your goal (lose weight, maintain, gain muscle) for ±500 kcal targets and macro split suggestions.
Calorie Deficit & Weight Loss Calculator
Calculate your daily calorie target for weight loss from body stats, activity, goal weight, and timeline. See TDEE, required deficit, estimated weeks to goal, and safety warnings.
Healthy Weight Gain & Muscle Building Calculator
Calculate your daily calorie surplus and target for healthy weight gain from body stats, activity, goal weight, goal type, and timeline. See TDEE, macro split, weekly gain rate, goal date, and safety warnings.
Weight Loss Goal & Timeline Calculator
Project your weight loss timeline from current and goal weight, body stats, activity, and weekly loss rate. See goal date, duration, daily calorie target, 4-week milestones, and realistic vs aggressive comparison.