Ideal Weight Calculator: What Should You Weigh?

"Ideal weight" formulas turn your height and sex into a single reference weight. They are quick, but they ignore muscle and frame size, so the useful answer is a range: the formulas' results combined with the BMI healthy range for your height.

Understanding Ideal Weight: More Than Just Numbers

There is no single "perfect" weight for everyone of the same height. Clinicians use several formulas as reference points. The Hamwi formula (1964) gives women 100 pounds for the first 5 feet of height plus 5 pounds for each additional inch, and men 106 pounds plus 6 pounds per inch. A 5'6" woman therefore gets 100 + (5 × 6) = 130 pounds; a 5'6" man, 106 + (6 × 6) = 142 pounds.

These formulas don't account for muscle mass or bone structure, so a muscular athlete can weigh well above the result and be perfectly healthy. Hamwi himself suggested adjusting by about 10% up or down for large or small frames.

Why Build and Muscle Change the Answer

Two people of the same height and weight can have very different amounts of muscle and fat. Someone with a small frame and little muscle may be healthiest near the bottom of the range for their height, while someone with a broad frame and a lot of muscle may be healthy above it. For a 5'8" man, the BMI healthy range runs from about 122 to 164 pounds; a muscular man of that height at 175 pounds (BMI 26.6) can still have low body fat. Body composition says more than the scale here.

The Role of BMI and Its Limitations

Body Mass Index (BMI) is weight in kilograms divided by height in meters squared. The BMI Calculator shows where you fall.

The CDC's adult categories are underweight (below 18.5), healthy weight (18.5 to under 25), overweight (25 to under 30) and obesity (30 and above). For someone 5'10", that is about 129–173 pounds for a healthy weight, 174–208 pounds for overweight, and about 209 pounds and up for obesity.

BMI has the same blind spot as the ideal-weight formulas: it can't tell muscle from fat. A 5'10" bodybuilder weighing 200 pounds has a BMI of 28.7, "overweight", despite low body fat. It also ignores where fat is stored and age-related muscle loss.

How to Use the Ideal Weight Formulas

Each formula takes your height in inches over 5 feet and your sex and returns a weight. Devine (1974) gives men 50 kg and women 45.5 kg, plus 2.3 kg per inch over 5 feet; Robinson (1983) uses 52 kg + 1.9 kg per inch for men and 49 kg + 1.7 kg per inch for women; Miller (1983) uses 56.2 kg + 1.41 kg per inch and 53.1 kg + 1.36 kg per inch; Hamwi is the metric version of the pounds formula above. The Ideal Weight Calculator runs any of the four from your height (in inches or centimeters), sex and frame size and returns pounds or kilograms; a small frame lowers the result by 5% and a large frame raises it by 5%, a convention rather than part of the formulas.

Measure your height without shoes, standing straight against a wall. For a 5'5" (65-inch) woman, Devine gives 45.5 + 2.3 × 5 = 57.0 kg, about 126 pounds. Robinson gives 57.5 kg (127 pounds) and Miller 59.9 kg (132 pounds) at the same height, which shows how much the choice of formula alone moves the answer. The BMI healthy range at 5'5" is about 111–150 pounds, so treat any formula's number as one point inside a wider healthy zone.

Use the results as a starting point for a conversation with a clinician rather than a fixed target; none of these formulas is a medical assessment.

Practical Steps to Achieve Your Ideal Weight

A moderate calorie deficit of 500–750 calories a day, through diet and activity, works out to roughly 1–1.5 pounds a week at first.

Focus on whole foods including lean proteins (chicken, fish, legumes), complex carbohydrates (quinoa, sweet potatoes, oats), and healthy fats (avocados, nuts, olive oil). A practical example: replace a 400-calorie fast food breakfast sandwich with a 250-calorie veggie omelet and whole grain toast, saving 150 calories while improving nutrition.

Combine aerobic exercise and strength training: the U.S. Physical Activity Guidelines recommend at least 150 minutes of moderate activity (such as brisk walking) a week plus muscle-strengthening activity on two or more days. Strength training helps keep muscle while you lose fat.

Track more than the scale: body measurements, how clothes fit, energy. Weight can swing by a few pounds from day to day with water and food, so watch the trend over weeks.

Related guides

• BMI Calculator: What It Is and How to Use It
• Calorie Deficit: How to Calculate and Use It for Weight Loss

Sources

• CDC — Adult BMI Categories
• Pai & Paloucek, Annals of Pharmacotherapy 2000 — The Origin of the "Ideal" Body Weight Equations (author copy)
• American College of Cardiology — 2013 AHA/ACC/TOS Guideline for the Management of Overweight and Obesity in Adults (summary)
• CDC — Adult Activity: An Overview (Physical Activity Guidelines for Americans)