⚖️ Ideal Weight Calculator

What This Calculator Does

This calculator shows what the established ideal-weight formulas estimate for your height and sex — the Devine and Robinson equations — alongside the weight range corresponding to a healthy BMI. Enter your height and it presents all three in kilograms and pounds, giving you a rounded, honest view rather than a single misleading “perfect” number.

People search for ideal weight expecting one answer, but the truthful response is a set of estimates that roughly agree — and understanding why they differ is more useful than any one figure. This tool shows the numbers and the context together, as general reference, not a personal prescription.

Where These Formulas Come From

The Devine formula (1974) is the best known: 50 kg (men) or 45.5 kg (women) plus 2.3 kg for every inch of height over five feet. Notably, it was created for calculating medication doses, not as a health target — a fact worth knowing given how widely it is quoted. The Robinson formula (1983) is a later refinement with slightly different coefficients, typically producing a modestly different figure for the same height.

The healthy BMI range takes a different approach: instead of one number, it computes the span of weights that put your BMI between 18.5 and 24.9 — the range health organizations classify as normal. For most heights this span covers well over 15 kg, which is a more honest representation of reality: healthy weight is a range shaped by build and composition, not a point. Seeing the formulas land inside (usually mid) that range puts their single numbers in proper perspective.

Reading the Results Honestly

The right way to use these figures is as orientation, not obligation. None of the formulas knows your muscle mass, bone structure, or body composition — a muscular athlete can sit far above every formula while being demonstrably healthier than someone at the “ideal” number. Frame size alone shifts genuinely healthy weight by several kilograms. So if your weight sits inside the healthy BMI range and your health markers are good, a formula suggesting a different number is not evidence anything is wrong.

Where the figures help is as rough anchors: understanding roughly where height-based estimates sit, sanity-checking goals, and — in clinical contexts — supporting dosing calculations, which is what Devine was actually built for. What they should not become is a fixation; chasing a formula's exact output has no health basis. For a personal target that accounts for your actual body and history, a healthcare professional's assessment outranks every equation here. This tool is general reference information, not medical advice.

Better Questions Than a Single Ideal Number

If the goal behind looking up ideal weight is health, several measures answer it better than any height formula. Waist circumference — and waist-to-height ratio, with the rough guide of keeping waist under half your height — tracks the abdominal fat that carries most metabolic risk, something no ideal-weight equation sees. Body composition (how much of your weight is muscle versus fat) explains why two people at the identical “ideal” weight can have opposite health profiles. And ordinary clinical markers — blood pressure, blood sugar, lipids, fitness — are the outcomes the weight number is merely a proxy for. A formula output is a single blurry snapshot; these are the actual picture.

There is also a better way to use the scale itself: as a trend instrument rather than a verdict. Direction and rate of change over months, measured consistently, carry far more information than distance from a computed ideal. Someone moving steadily from 95 kg toward 88 with improving energy and blood work is succeeding regardless of what Devine says about their height; someone at their formula-perfect weight through unsustainable restriction is not. The honest hierarchy runs: health markers and how you feel first, waist and composition second, weight trend third, and formula ideals last — as historical reference points, which is what they genuinely are. This calculator shows them for that purpose, not as a finish line.

Quick Tips

• Devine and Robinson differ slightly by design — the spread shows how approximate 'ideal' is.
• The healthy BMI range (18.5-24.9) is a span of 15+ kg for most heights — weight is a range, not a point.
• Muscle, frame, and health markers matter more than any formula output.
• Use the figures as orientation; for personal targets, ask a healthcare professional.

Frequently Asked Questions

How is ideal weight calculated?

This tool shows two classic height-based formulas — Devine and Robinson — plus the weight range corresponding to a healthy BMI (18.5-24.9) for your height. Each gives a slightly different figure, which is itself informative: 'ideal weight' is an estimate, not a single true number.

Why do the formulas give different answers?

Because each was derived differently — Devine was created for drug dosing, Robinson as a refinement of it — and none accounts for muscle mass, frame size, or body composition. The spread between them is a realistic picture of how approximate the concept is.

Is the healthy BMI range a better guide?

It is broader and arguably more honest: rather than one number, it shows the full weight span considered healthy for your height. Many people's genuinely healthy weight sits anywhere within that range depending on build and muscle.

Should I aim for my 'ideal weight'?

Treat these figures as general reference points, not prescriptions. Muscle mass, frame, age, and health markers all matter more than a formula output — a muscular person can be perfectly healthy well above these numbers. For personal targets, a healthcare professional beats any formula.

Reference Information, Free to Use

This calculator runs entirely in your browser and presents standard formulas for general reference — it is not medical advice. It works instantly, needs no account or download, and runs on any device. Like every tool here, it is free to use as often as you like.

Related Tools

For related tools, the BMI calculator computes your actual BMI, the calorie deficit calculator estimates maintenance calories, and the weight converter switches kg and lbs.