Ideal Weight Calculator
Estimate your ideal weight for your height and sex using the Devine and Robinson formulas plus your healthy BMI weight range — in centimeters or feet and inches, with results in both kg and lb.
General nutrition education only. Not medical advice.
Quick answer: how to use this result
This ideal weight calculator gives you an estimated healthy weight range for your height and sex — not a single perfect number. It shows three well-known reference points: the Devine formula estimate, the Robinson formula estimate, and the weight range that matches a healthy BMI of 18.5–24.9. Pick the height unit you prefer (cm or feet and inches), read the range, and treat it as general context. If you enter your current weight, the tool shows how far you sit from the range in neutral terms. To turn a goal into daily calories, pair it with the Calorie Deficit Calculator.
What "ideal weight" really means
An ideal weight is best understood as a healthy range rather than an exact target. The formulas on this page were designed decades ago — Devine for medication dosing, Robinson and others as refinements — to estimate a reasonable body weight from height and sex alone. They are quick and useful for context, but they cannot see your muscle mass, frame size, age, or body composition. That is why this ideal weight calculator reports a span of estimates and pairs them with your healthy BMI weight range, so you get a realistic window instead of a false sense of precision.
Two people of the same height can both be healthy at noticeably different weights. A person who lifts weights carries more muscle, which is denser than fat, so their healthy weight sits higher than a formula predicts. Someone with a smaller frame may feel best toward the lower end. Read the result as a guide, and combine it with other signals such as waist size, energy, strength and how your clothes fit.
How to use this result
Enter your sex and height, choosing centimeters or feet and inches. Optionally add your current weight in kg or lb to see the difference from the estimated range. The calculator then shows the Devine estimate, the Robinson estimate, and the healthy BMI range, plus a short, neutral interpretation. If your weight already sits inside the range, that is shown plainly; if it sits above or below, the tool reports the approximate gap without judgement. Nothing here is a verdict on your health — it is a starting point for a conversation with yourself or a qualified professional.
Ideal weight formulas explained
All three methods below share the same idea: start from a base weight at five feet of height, then add weight for each inch above that. They differ in the starting point and the increment.
Devine formula
Men: 50 kg + 2.3 kg for each inch over 5 feet.
Women: 45.5 kg + 2.3 kg for each inch over 5 feet.
The Devine formula (1974) is the most widely used, particularly in clinical settings for calculating medication doses. It tends to sit in the middle of the estimates.
Robinson formula
Men: 52 kg + 1.9 kg for each inch over 5 feet.
Women: 49 kg + 1.7 kg for each inch over 5 feet.
The Robinson formula (1983) refined Devine using additional data. Because its per-inch increment is smaller, it usually returns a slightly lower estimate for taller people.
Healthy BMI weight range
The healthy BMI band runs from 18.5 to 24.9. To turn that into a weight range, multiply each BMI value by your height in metres squared: weight = BMI × height(m)². For someone 1.80 m tall, that is roughly 18.5 × 1.80² ≈ 60 kg at the low end and 24.9 × 1.80² ≈ 81 kg at the high end. This range naturally accommodates different frames and is often the most practical reference of the three.
Ideal weight vs BMI
BMI and ideal weight answer the same question from two directions. BMI takes your weight and height and returns a single number you compare to categories; an ideal weight estimate takes your height and returns the weight that would land you in a healthy zone. Neither can distinguish muscle from fat. If your formula estimate and your BMI disagree with how you look and feel, that usually means body composition — not the scale — is telling the real story. You can check your current number with the BMI Calculator and estimate maintenance calories with the TDEE Calculator.
Ideal weight vs body fat percentage
Where ideal weight and BMI look only at the scale, body fat percentage looks at what your weight is made of. A muscular person can sit above their "ideal weight" range yet carry very little fat, while another person at the same weight may carry more. That is why a body fat estimate adds information the scale cannot: it splits your weight into fat mass and lean mass. If you want a fuller picture, run the Body Fat Percentage Calculator alongside this one, and consider tracking your waist-to-height ratio too.
Ideal weight for South Asian users
Formulas like Devine and Robinson were built largely on Western populations, so South Asian users may find the numbers only a rough guide. Research suggests that people of South Asian descent can carry more central (abdominal) fat at a given weight or BMI, which is why height and the scale alone rarely tell the whole story. Rather than fixating on a single ideal weight figure, it is often more useful to watch a combination of signals: your weight trend, your waist measurement, your body composition, and your daily habits around food and movement. Tracking your waist-to-height ratio in particular can add helpful context that a weight-for-height formula misses. As always, this is general education — a qualified health professional can give guidance tailored to you.
Example calculation
Take a man who is 5 ft 11 in (about 180 cm). That is 11 inches over five feet. The Devine estimate is 50 + (2.3 × 11) ≈ 75.3 kg. The Robinson estimate is 52 + (1.9 × 11) ≈ 72.9 kg. His healthy BMI range at 1.80 m runs from about 60 kg (BMI 18.5) to about 81 kg (BMI 24.9), or roughly 132–178 lb. So a reasonable "ideal weight" window for him sits in the low-to-mid 70s kg, comfortably inside the healthy BMI band. The takeaway is not a single magic number but a range — anywhere in the 70s here would be unremarkable for his height, and where he feels and performs best within that band is individual.
Turning your estimate into a plan
If your goal is to move toward the range, the reliable sequence is the same one that works for body composition generally: find your maintenance calories with the TDEE Calculator, set a moderate deficit with the Calorie Deficit Calculator, keep protein adequate using the Protein Calculator, and plan meals with the Meal Planner. Day to day, the Food Compare tool, the Food Comparisons library and the Food Calories Database help you find lighter, higher-protein versions of the meals you already enjoy.
FAQs: ideal weight calculator
What is an ideal weight calculator?
An ideal weight calculator estimates a healthy body weight range for your height and sex using established formulas such as Devine and Robinson, alongside the weight range that matches a healthy BMI. It gives you a realistic target range rather than one exact number, so you can see roughly where a healthy weight sits for someone of your height.
What is the best ideal weight formula?
No single formula is best for everyone. The Devine formula is the most widely used, especially in medicine for dosing, while the Robinson formula tends to give slightly lower estimates. The healthy BMI range is often the most practical because it naturally produces a range rather than a single figure. Comparing all three gives the most balanced picture.
Is ideal weight the same as BMI?
They are related but not identical. BMI is a ratio of weight to height squared, while an ideal weight estimate converts that idea into an actual weight in kilograms or pounds. This calculator shows both: the Devine and Robinson formula estimates and the weight range that corresponds to a healthy BMI of 18.5 to 24.9.
Can I use feet and inches instead of centimeters?
Yes. Switch the height unit to feet and inches and enter your height as, for example, 5 feet and 8 inches. The calculator converts your height internally and returns the same result you would get by entering the equivalent value in centimeters, so you can use whichever unit feels natural.
Why do different formulas show different ideal weights?
Each formula was built from a different population and set of assumptions, so they weight height slightly differently. Devine and Robinson both add weight for every inch above five feet but use different starting points and increments. Small differences are normal, which is why an ideal weight is best treated as a range spanning the estimates.
Should I lose weight if I am above the ideal weight range?
Not necessarily. These formulas do not account for muscle mass, frame size, age or body composition, so a muscular person can sit above the range while being perfectly healthy. Use the estimate as general context, look at waist size and how you feel, and speak with a qualified health professional before setting any weight goal. This tool is educational only and not medical advice.
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General nutrition education only. Not medical advice. Ideal weight formulas are estimates and do not account for muscle, frame or body composition; consult a qualified professional for individual guidance.