This ideal weight calculator gives you a range instead of one number, because the four formulas doctors actually use disagree with each other by ten pounds or more. Your height, your sex and your frame size all move the answer.
Enter your height and the calculator runs the Devine, Robinson, Miller and Hamwi equations side by side. It also shows the healthy weight range that comes from BMI, which is usually wider than people expect.
Why This Ideal Weight Calculator Shows a Range
Most ideal weight calculators give you one confident number. That number hides a problem. Four different equations sit behind these tools, their authors wrote them decades apart, and they disagree.
A man of 5 feet 10 inches gets 73 kilos from Devine, 71 from Robinson, 70 from Miller and 75 from Hamwi. None of those is more correct than the others. The spread between them is the real answer, so this calculator shows all four and the range they create.
The Four Formulas and Where They Came From
Every formula follows the same shape. Start with a base weight at 5 feet, then add a fixed amount for each inch above that.
| Formula | Year | Men | Women |
|---|---|---|---|
| Hamwi | 1964 | 48.0 kg plus 2.7 kg per inch | 45.5 kg plus 2.2 kg per inch |
| Devine | 1974 | 50.0 kg plus 2.3 kg per inch | 45.5 kg plus 2.3 kg per inch |
| Robinson | 1983 | 52.0 kg plus 1.9 kg per inch | 49.0 kg plus 1.7 kg per inch |
| Miller | 1983 | 56.2 kg plus 1.41 kg per inch | 53.1 kg plus 1.36 kg per inch |
Devine wrote his equation to help pharmacists dose gentamicin, not to give anyone a fitness target. Hamwi built his for diabetes meal planning. Robinson and Miller came later and tried to fit real population data more closely, which is why their numbers run flatter for tall people.
That history matters. These equations were never designed to tell you what to weigh. They estimate a reasonable weight for a body of a given height, and clinicians still use them for exactly that.
Your Frame Size Shifts the Answer
Two people of the same height can carry very different amounts of bone. Frame size accounts for that, and the standard adjustment moves the result by 10 percent in either direction.
Wrap your thumb and middle finger around the opposite wrist to test it. Fingers that overlap point to a small frame. Fingers that just touch point to medium. Fingers that do not meet point to large.
A tape measure gives a firmer answer. Measure your wrist just below the wrist bone, then compare against your height. Our body frame size calculator does that comparison for you and shows what it does to the figures above.
| Group | Small | Medium | Large |
|---|---|---|---|
| Women under 5 ft 2 in | Under 5.5 in | 5.5 to 5.75 in | Over 5.75 in |
| Women 5 ft 2 in to 5 ft 5 in | Under 6 in | 6 to 6.25 in | Over 6.25 in |
| Women over 5 ft 5 in | Under 6.25 in | 6.25 to 6.5 in | Over 6.5 in |
| Men over 5 ft 5 in | Under 6.5 in | 6.5 to 7.5 in | Over 7.5 in |
What Ideal Weight Cannot Tell You
The scale weighs everything at once. Muscle, fat, bone, water and the food in your stomach all land in the same number, and no height based formula can separate them.
Two men of 5 feet 10 inches at 85 kilos can look nothing alike. One carries 14 percent body fat and lifts four times a week. The other carries 30 percent and does not. The formulas call both of them heavy. Our body fat calculator tells the two apart with a tape measure.
Use ideal weight as a rough map of the territory. Use body fat percentage to see where you actually stand on it.
The Healthy Weight Range Is Wider Than Most People Think
The World Health Organization sets the healthy adult band at a BMI of 18.5 to 24.9, and counts a BMI of 25 or more as overweight. For someone of 5 feet 7 inches that band runs from about 118 to 159 pounds.
Forty pounds of healthy range surprises people who grew up chasing one target figure. Where you sit inside that band depends on your muscle, your frame and what feels sustainable for you.
Health markers also improve long before anyone reaches a formula weight. A loss of 5 to 10 percent of current body weight lowers blood pressure, blood sugar and triglycerides, and the National Institute of Diabetes and Digestive and Kidney Diseases treats that as a genuine success rather than a halfway point.
How to Move Toward Your Range Safely
Slow change sticks. Fast change takes muscle with it and comes back.
Set a modest deficit. Aim for half a pound to one pound a week. Work out your maintenance calories first with our daily calorie calculator, then eat 300 to 500 below it.
Eat enough protein. Protein protects muscle while you lose fat and keeps you full between meals. Our protein intake calculator sets your daily target.
Get your fiber up. Fiber slows digestion and blunts hunger, and most adults fall well short. Check the gap with our fiber intake calculator.
Weigh yourself the same way. Same day of the week, same time, after the bathroom and before breakfast. Daily weight swings by several pounds on water alone.
Who Should Skip This Calculator
Height based formulas assume an average adult body, so several groups get numbers that mislead.
Athletes and regular lifters. Muscle weighs more than the formulas expect, and a healthy athlete often reads as overweight.
Children and teenagers under 18. Growth charts do this job properly. These equations do not.
Pregnant and breastfeeding women. Weight targets shift through pregnancy and your provider should set them.
Adults over 65. Slightly higher weight carries a survival advantage in later life, so the standard band sits low for this group.
Anyone with a history of disordered eating. A target weight can do real harm here. Speak to your clinician first.
Frequently Asked Questions
Which ideal weight formula is the most accurate?
None of them wins outright. Robinson and Miller fit population data better for tall people, while Devine and Hamwi remain standard in clinical dosing. The range across all four is more useful than any single figure.
Why is my ideal weight different from my BMI healthy range?
The formulas give one point and BMI gives a band. The healthy BMI range covers about 40 pounds for an average adult, and every formula result sits somewhere inside it.
How do I know my frame size?
Wrap your thumb and middle finger around the opposite wrist. Fingers that overlap mean a small frame, fingers that touch mean medium and a gap means large. A wrist measurement compared against your height gives a firmer answer.
Does ideal weight change with age?
The formulas ignore age completely. Research suggests a slightly higher weight benefits adults over 65, so treat the result as a young adult figure.
Should athletes use this calculator?
No. Muscle weighs more than these equations assume, so trained athletes often land well above their formula weight while carrying very little fat. Body fat percentage suits them better.
Is this ideal weight calculator free?
Yes. No sign up, no email and no limits. Everything runs in your browser and nothing leaves your device.
Final Thoughts on Your Ideal Weight Calculator Result
An ideal weight calculator works best as a sanity check rather than a goal. The four formulas disagree, the healthy BMI band is wide, and your frame moves every figure by a tenth in either direction.
Pick a point inside your range that you can hold without a fight, then judge progress by how you feel, how your clothes fit and what your body fat percentage does. Browse the rest of our free health calculators to fill in the numbers around it.
This calculator provides a general estimate for healthy adults and does not replace advice from your doctor or a registered dietitian. Read our full medical disclaimer and fact checking policy.