Ideal Weight Calculator

“What should I weigh?” has been given a suspiciously precise answer for fifty years — single-number formulas, printed on charts, quoted to the kilogram. This ideal weight calculator gives you that classic number (the Devine formula doctors still use for drug dosing), and then does what most pages won’t: shows you the honest version, where ideal weight is a range shaped by frame, muscle and health — not a target etched in stone.

Calculate below, then read on: the formulas compared, the healthy range for your height, adjusted body weight, and why “ideal” deserves its quotation marks.

What is ideal body weight?

The term comes from two different worlds. In clinical medicine, ideal body weight (IBW) is a reference value computed from height and sex — used to dose certain medications, size ventilator volumes and calculate nutrition targets, jobs where a standardized number is exactly what’s needed. In everyday life, “ideal weight” means the weight at which you are healthiest — and that is a range, typically the weight band that puts your BMI between 18.5 and 24.9, refined by body composition. The calculator gives the first; the tables below give the second.

Ideal body weight formula: Devine and friends

Four formulas dominate, all built as a base weight at 5 feet (152.4 cm) plus an increment per inch above:

For a 170 cm man the four give roughly 66, 65, 66 and 67 kg — reassuringly close mid-range, drifting apart at height extremes. None of them saw your body; all of them assume an average build.

Healthy weight range by height

The more useful everyday answer — the band corresponding to a healthy BMI (18.5–24.9):

Notice the Devine number sits comfortably inside each range — the formulas and the range agree; the range just tells the truth about the width. Our BMI calculator computes your exact band.

Adjusted body weight

Clinicians use a third value for people well above their IBW: adjusted body weight = IBW + 0.4 × (actual weight − IBW). It exists because some drugs and nutrition calculations scale with lean tissue rather than total weight, and using either extreme misdoses. If you see “AdjBW” on a clinical document, this is what it means — and like all dosing math, it belongs to your care team, not a website.

Healthy weight for women and men: what actually differs

The formulas encode one difference — women’s reference weight runs about 4–5 kg lighter at the same height — but the meaningful differences are compositional: women healthily carry more essential fat (10–13% vs 2–5%), men more muscle mass, and fat sits in different places. Two people at the same “ideal weight” can look and measure completely differently. That is why the modern answer to “am I at a good weight?” combines three tools: weight against the healthy band, our body fat calculator for composition, and the waist-to-height ratio for fat placement — with lean body mass completing the picture for athletes.

Frame size: the adjustment the formulas skip

Skeletal frame shifts healthy weight several kilograms without a gram of fat involved — and the classic quick test is the wrist: circumference relative to height sorts people into small, medium and large frames (for ~165–190 cm adults, roughly: men under 16.5 cm small / over 19 cm large; women under 15 cm small / over 16.5 cm large). The traditional correction applies ±10% to the formula weight — a large-framed 178 cm man’s Devine 73 kg becomes an honest ~80 kg. Elbow breadth does the same job more formally. The point isn’t precision — it’s permission: if you’re large-framed and every chart calls you heavy at your leanest, the chart is missing a variable you can measure with a tape in ten seconds.

Ideal weight after 60: the rules soften

The evidence in older adults is consistent and counterintuitive: the lowest-mortality BMI band drifts upward (roughly 23–28), modest reserves protect through illness and hospitalization, and unintentional weight loss is a stronger danger sign than mild overweight ever was. The reframe: after 60, the enemy isn’t the number on the scale but sarcopenia — muscle loss — which dieting without resistance training actively accelerates. Priorities invert accordingly: protein at 1.0–1.2 g/kg, strength work twice weekly, and weight loss pursued only deliberately, with medical guidance, for specific conditions (joints, diabetes, surgery prep) — never as chart-chasing. Our lean body mass calculator tracks the tissue that actually matters at this stage.

Setting your personal target weight

A target worth pursuing survives four filters: it sits inside the healthy band for your height (or moves toward it); it’s a weight you have actually maintained as an adult without white-knuckling (history beats aspiration); the waist agrees (waist under half your height matters more than the scale figure); and the rate to get there is sustainable — 0.25–0.5 kg weekly via the calorie deficit calculator, reassessed every 5 kg. If a “dream weight” fails the second filter, aim for the weight you maintained easily at your fittest instead — a 5–10% loss from today already delivers most of the measurable health benefit, which makes the perfect number a poor enemy of the good one.

Why “ideal” is a range, not a target

Frame size shifts healthy weight by several kilograms in either direction. Muscle moves it up without harm — an athlete can be “overweight” by every chart while metabolically excellent. Age matters: in adults over about 65, slightly higher weight is associated with better outcomes, and aggressive dieting toward a chart number can cost muscle and bone. The honest use of any ideal-weight number: as the centre of a personal range, pursued — if at all — through sustainable habits, with our calorie deficit calculator or weight gain calculator setting the realistic pace in whichever direction.

Frequently asked questions

How much should I weigh for my height?

For most adults, the healthy band spans BMI 18.5–24.9 — about a 15 kg range at any height. The Devine formula gives a single clinical reference point near the middle of it.

What is the Devine formula?

Men: 50 kg + 2.3 kg per inch over 5 feet. Women: 45.5 kg + 2.3 kg per inch. Published in 1974 for drug dosing, still the clinical standard reference.

Why is my ideal weight different on different calculators?

Different formulas (Devine, Robinson, Miller, Hamwi) use different base weights and slopes. They agree within a few kilograms mid-height and diverge for very short or tall people — treat all of them as reference points.

What is adjusted body weight?

A clinical value between ideal and actual weight — IBW + 40% of the excess — used for certain drug doses and nutrition calculations in people well above their IBW.

Is ideal weight different for women?

The reference formulas run about 4–5 kg lighter for women at the same height, reflecting average composition differences. The healthy BMI band is the same for both sexes.

Should I diet down to my Devine weight?

Not as a rule — it is a reference, not a goal. If your weight, waist and body fat sit in healthy ranges, chasing a chart number adds risk, not health. If they don’t, target the healthy range gradually with professional guidance.

How do I know my frame size?

The wrist test: measure its circumference and compare against height-adjusted cutoffs — roughly, under 15–16.5 cm reads small-framed and over 16.5–19 cm large, by sex and height. Large frames legitimately carry ~10% above formula weights.

Does ideal weight increase with age?

The healthiest observed range drifts modestly upward after 60 (BMI ~23–28), and unintentional loss becomes the bigger warning sign. Muscle preservation outranks scale-chasing in later life.

Is a 5–10% weight loss really worth it?

Yes — that modest loss measurably improves blood pressure, lipids, glucose and joint load, delivering most of the health benefit long before any “ideal” number is reached.