An ideal weight calculator estimates the body weight that's medically and aesthetically associated with low health risk for your height and frame. Five different formulas exist (Devine, Robinson, Miller, Hamwi, plus the healthy BMI range), and they often disagree by 10–20 lb. None of them is 'right' — they all reflect averages from different historical populations. This page covers what each formula assumes, why your ideal weight is a range not a number, and how to use the calculator output without making it a fixation.
TDEE Calculator
Total Daily Energy Expenditure — your real maintenance calories.
Biological sex
BMR formulas use biological sex, not gender identity.
Leave blank if unsure — we'll fall back to Mifflin-St Jeor (the standard).
Most people overestimate this. When in doubt, drop one tier.
The medical concept of 'ideal weight' was originally developed in the 1950s and 1960s by insurance companies looking at mortality data — what body weight correlated with the lowest death rates? Those tables, plus subsequent revisions, are the ancestors of every formula on this page. They're statistical averages, not personal prescriptions.
More recent definitions emphasize body composition over body weight. A muscular 180 lb male at 12% body fat is in better health than a 165 lb male at 30% body fat, even though both might match different 'ideal' formulas. Modern sports medicine focuses on lean body mass and body fat percentage rather than total body weight.
For most adults, 'ideal' is a range, not a point. A 5'10" man's ideal weight from various formulas falls between 160 and 185 lb. A 5'5" woman's ideal weight falls between 115 and 140 lb. Anywhere in those ranges is generally fine, and the variation reflects bone structure, muscle mass, and personal aesthetic preference.
Ideal weight formulas compared (5'8" / 173 cm adult)
Five different formulas give five different numbers for the same height. None is uniquely correct.
Formula
Year
Male
Female
Notes
Hamwi (1964)
1964
168 lb
145 lb
Original 'ideal body weight' formula, used in medical contexts.
Devine (1974)
1974
165 lb
150 lb
Developed for drug dosing. Widely used clinically.
Robinson (1983)
1983
163 lb
144 lb
Refined Devine; slightly lower.
Miller (1983)
1983
157 lb
143 lb
Lowest of the four formulas.
Healthy BMI range (18.5–24.9)
WHO
122–164 lb
122–164 lb
Same range for both sexes.
The healthy BMI range is wider than the formula ideals because BMI is height-only — it doesn't differentiate sex or frame. Use it as a sanity check, not as a target.
When the formula numbers don't apply to you
Common cases where 'ideal weight' formulas mislead:
Muscular lifters. A 5'10" man with significant muscle mass at 175 lb is at a healthier body composition than the 165 lb formula 'ideal' for that height — but the BMI may classify him as overweight. Body composition beats body weight.
Very tall or very short people. Formulas extrapolated from average-height populations get less accurate at the height extremes. Adjust expectations.
Older adults. Holding 5–10 lb of extra body fat into your 60s and 70s is associated with better outcomes than being at 'ideal' weight — a phenomenon called the obesity paradox in geriatric medicine.
Athletes. Formula 'ideal' weights for sprinters, gymnasts, and bodybuilders are wrong by 20+ lb in either direction depending on the sport.
People recovering from eating disorders. Formula targets can be triggering and shouldn't be used as cut targets — work with a clinician, not a calculator.
Field note from Sukie
The friend who chased 'ideal weight' instead of body composition
A friend (call him R) was 5'10", 195 lb, and the Devine formula said his ideal was 165 lb. He set a goal to lose 30 lb. After 6 months and a lot of effort, he hit 165. He also looked worse than he had at 195. His shoulders had narrowed, his lifts had dropped 15-20%, his face looked drawn, and his energy was low.
He'd lost about 22 lb of fat and 8 lb of muscle to hit the number. The number was the wrong goal. What he actually wanted (visible abs, defined arms, athletic look) was a body composition outcome — and you don't get there by minimizing weight; you get there by reducing fat while preserving muscle.
He reset. We dropped the weight target entirely and focused on body composition. He spent 6 months at maintenance with hard lifting, regained the muscle plus a little more, and ended up at 178 lb with visible abs and 16-inch arms. The number was higher than the 'ideal' but the look was what he'd wanted all along. Ideal weight is the wrong frame for most physique-driven goals.
— Sukie
How to use the calculator output
The ideal weight calculator on this page gives you four formula numbers plus the healthy BMI range. Here's how to interpret them:
If you're overweight: the formulas give a rough target zone. Aim to land somewhere in the range — not necessarily the lowest formula's number. Reaching the high end of the healthy BMI range (24.9) is fine if you're carrying meaningful muscle mass; reaching the middle (~22) is reasonable for typical body composition.
If you're at the high end of healthy BMI: you may not need to lose weight at all. Check body composition (waist circumference, body fat % if you have access to measurement) before assuming weight loss is the right goal.
If you're at 'ideal' weight but unhappy with how you look: body composition is the goal, not the number. Recomposition (losing fat, gaining muscle) at maintenance calories changes how you look without changing the scale.
If you're below ideal weight and have been losing: stop. The formulas are floors as much as ceilings. Below the formula ranges, especially after intentional restriction, you may be at risk of nutritional inadequacy or under-recovery.
What to track instead of (or alongside) body weight
Body weight is one metric. For body composition goals, more useful metrics include:
Waist circumference. Measured at the navel, this correlates with visceral fat better than body weight. Healthy targets: under 35" for women, under 40" for men. Track once a month.
Waist-to-hip ratio. Waist divided by hips. Healthy: <0.85 for women, <0.90 for men. Predicts cardiovascular risk better than BMI.
Progress photos. Front, side, back, same time of day, same conditions, monthly. The mirror shows changes the scale and tape miss.
Clothing fit. The pants test — does a benchmark pair of pants fit looser, the same, or tighter than last month? Combined with weight, this reveals recomposition (loose pants, stable weight = lost fat, gained muscle).
Lifts. For lifters, key lift numbers tell you whether you're recomposing well. Holding or progressing lifts while weight stays flat = muscle gain is matching fat loss. Losing lifts while weight drops = you're losing muscle alongside fat.
None of these need to replace body weight tracking, but combined with weight they paint a complete picture that 'ideal weight' alone can't.
Where the classic ideal-weight formulas actually come from
The four formulas you'll see in every ideal-weight calculator (Hamwi, Devine, Robinson, Miller) all share a similar origin story: they were developed by clinicians who needed a quick way to estimate medication dosing, not to give individual humans a fitness target.
Hamwi (1964): the oldest of the bunch. G.J. Hamwi was a diabetes researcher who needed a rule-of-thumb for estimating ideal body weight to dose insulin and calculate caloric needs in diabetic patients. The formula (men: 106 lb + 6 lb per inch over 5 feet; women: 100 + 5 per inch) is famously simple but tends to underestimate for shorter individuals.
Devine (1974): developed by pharmacist Ben J. Devine to make aminoglycoside antibiotic dosing more accurate. Devine wanted a formula that gave a target lean body weight, since antibiotics distribute through lean tissue, not fat. It remains the medical default for drug dosing today — which means it's optimized for pharmacokinetic accuracy, not for what looks good in a mirror.
Robinson (1983) and Miller (1983): both attempted refinements of Devine using larger sample sets. Robinson tends to come in slightly lower than Devine; Miller slightly higher. Neither is dramatically more accurate.
None of these formulas were validated against body composition data. They were validated against pharmacokinetic outcomes. Treating them as 'the weight you should aim for' is using them outside their intended domain. The right way to use ideal-weight numbers is as a reference range — your healthy weight is almost certainly somewhere in the spread these formulas produce — not as a single target.
Ideal weight comparison across formulas (5'8" male)
Same person, four formulas. Notice how a 7-pound spread is normal — pick the range, not a single number.
Formula
Output (5'8" male)
Notes
Devine (1974)
164 lb
Built for drug dosing, slightly low for muscular builds
Robinson (1983)
160 lb
Refinement of Devine, even more conservative
Miller (1983)
162 lb
Bridge between Devine and BMI-based estimates
Hamwi (1964)
166 lb
Common in clinical nutrition
Healthy BMI range (18.5–24.9)
121–164 lb
The widest spread; spans actual healthy variation
Healthy BMI midpoint (BMI 22)
144 lb
Often a sensible long-term anchor
For the same 5'8" frame, formulas range from 144 to 166 lb depending on which definition you use. Treat any single number with suspicion. A 20-pound range centered on the healthy BMI midpoint is a more honest target than a precise number that ignores muscle mass, frame size, and personal preference.
Frequently asked questions
Which ideal weight formula is most accurate?+
Devine is the most widely used in medical contexts. Robinson and Miller are refinements. Hamwi is older and less commonly used today. For practical purposes, treat the range across all four as your target zone rather than picking one.
Is the healthy BMI range different from ideal weight?+
Yes. BMI is height-only and gives a wide healthy range (18.5–24.9). Ideal weight formulas account for sex and give a narrower target. BMI is a population screening tool; ideal weight formulas are individual estimates.
Should I weigh less than my 'ideal' to see abs?+
For visible abs, body fat percentage matters more than body weight. Most men need to drop to 10–13% body fat to see abs clearly; most women, 18–22%. You can hit those body fat levels at various total body weights depending on muscle mass.
Why do I weigh more than 'ideal' but look lean?+
Muscle is denser than fat. A lifter at 'overweight' BMI can look lean if body fat is low and muscle mass is high. The formulas don't account for body composition.
What's a good weight for my height and frame size?+
Most ideal weight formulas were calibrated for medium frames. Add 5–10% for large-frame; subtract 5–10% for small-frame. Frame size is roughly indicated by wrist circumference (larger wrist = larger frame).