How do I calculate my ideal body weight?

Enter your gender, height, and optional frame size into the calculator. It uses four clinical formulas (Devine, Robinson, Miller, Hamwi) plus a BMI-based range to estimate your ideal weight. Each formula uses height in inches relative to a 5-foot baseline.

What is the most accurate ideal weight formula?

The Devine formula is the most widely used in clinical settings, especially for drug dosing. However, no single formula is universally accurate. The Robinson and Miller formulas may be more appropriate for certain body types. Using all four and comparing the average gives the best estimate.

Does frame size affect ideal weight?

Yes. People with larger bone structures naturally weigh more. A small frame adjustment reduces the ideal weight estimate by 10%, while a large frame increases it by 10%. Medium frame uses the standard formula values.

What is a healthy BMI range?

A healthy BMI is between 18.5 and 24.9. The calculator shows the weight range that corresponds to this BMI range for your height, giving you an evidence-based healthy weight window regardless of gender.

Is ideal weight the same as healthy weight?

Not exactly. Ideal body weight formulas were developed for clinical purposes like drug dosing, not as universal health targets. A healthy weight depends on many factors including muscle mass, body composition, and overall health. The BMI-based range is a better indicator of general health.

Is this ideal body weight calculator free?

Yes, completely free with no signup required. Enter your height and gender, and get instant results from four clinical formulas plus a BMI-based healthy weight range.

Does muscle mass affect ideal body weight?

Yes. Ideal weight formulas don't account for muscle mass. A muscular person will weigh more than a sedentary person of the same height and be healthier. Combine ideal weight with body fat percentage and lean body mass measurements for a more complete picture.

How do I safely reach my ideal weight?

Aim for a gradual calorie deficit of about 500 calories per day for weight loss (0.5 kg per week). Prioritize protein at 1.6-2.2g per kg to preserve muscle. Avoid crash diets. If underweight, a slight caloric surplus with strength training builds lean mass. A personalized meal plan helps hit targets consistently.

Ideal Body Weight Calculator

Calculate your ideal body weight using four clinical formulas — Devine, Robinson, Miller, and Hamwi — plus a BMI-based healthy weight range. Optionally adjust for frame size.

Calculate Your Ideal Weight

Gender

Height

ft in

Frame Size (optional)

Current Weight (optional, for comparison)

What Is Ideal Body Weight?

Ideal body weight (IBW) is a clinical estimate of how much a person should weigh based on their height and gender. Originally developed for pharmaceutical dosing, these formulas are now widely used as general health reference points. No single number defines a "perfect" weight — these are guidelines, not absolutes.

Devine Formula (1974)

The most widely used formula in medicine, originally created for calculating drug dosages. It estimates 50 kg for a 5′ male (45.5 kg for female) plus an increment per inch over 5 feet. Simple and well-established, but may underestimate ideal weight for shorter individuals.

Robinson Formula (1983)

Developed as a refinement of the Devine formula with updated population data. It uses slightly different base weights and increments, often producing values closer to modern BMI-based ranges. A good alternative for people who find the Devine estimate too low.

Miller Formula (1983)

Tends to produce the highest estimates among the four formulas, making it potentially more realistic for people with larger builds or more muscle mass. Uses the same height-based structure but with higher coefficients.

Hamwi Formula (1964)

The oldest of the four formulas, originally published as a quick estimation method. It produces results similar to Devine for men but slightly different for women. Still referenced in many clinical nutrition guidelines.

When to Use Which Formula

No single formula is universally best. Using all four and looking at the average gives you a reasonable range. The BMI-based healthy weight range (18.5–24.9) provides an additional, widely-accepted reference point. For clinical decisions like drug dosing, the Devine formula remains the standard.

How Accurate Are Ideal Weight Formulas?

These formulas are population-level estimates and do not account for muscle mass, bone density, body composition, ethnicity, or age. A muscular athlete and a sedentary person of the same height will have very different ideal weights. Always consult a healthcare professional for personalized guidance.

Ideal Weight and Body Composition

Two people at the same height can have very different ideal weights depending on their body composition. A person with more muscle mass will naturally weigh more than someone with less muscle at the same height — and be healthier for it. Ideal weight formulas don't account for this. For a more complete picture, combine your ideal weight estimate with a body fat percentage measurement and lean body mass calculation.

How to Reach Your Ideal Weight Safely

If your current weight is above the formula average, aim for a gradual deficit of 500 calories per day (about 0.5 kg per week). Crash diets lead to muscle loss and metabolic slowdown. Prioritize protein (1.6–2.2g per kg) to preserve muscle during weight loss. If you're below the average, a slight caloric surplus with strength training helps build lean mass. Either way, a personalized meal plan makes it easier to hit your targets consistently without guesswork.

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Pro Tip

For a more complete picture, check your BMI and use our body fat calculator to estimate your body composition beyond just weight.

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Frequently Asked Questions

Enter your gender and height (in cm or feet/inches), and optionally select your frame size. The calculator applies four clinical formulas — Devine, Robinson, Miller, and Hamwi — plus a BMI-based healthy range. Each formula estimates weight relative to a 5-foot baseline height.

No single formula is universally best. The Devine formula is the clinical standard for drug dosing. Robinson and Miller formulas may be more realistic for certain body types. Comparing all four results and looking at the average alongside the BMI range gives the most balanced estimate.

Yes. People with smaller frames tend to weigh less, while larger frames support more weight. This calculator adjusts formula results by -10% for small frames and +10% for large frames. If you're unsure, leave it on Medium for the standard estimate.

A healthy BMI falls between 18.5 and 24.9. The calculator converts this BMI range into a weight range for your specific height, showing you the minimum and maximum weight considered healthy by the World Health Organization guidelines.

Not exactly. "Ideal weight" formulas were developed for clinical purposes like medication dosing, not as universal health targets. Healthy weight depends on body composition, muscle mass, age, and overall health. The BMI-based range is a better general health indicator. Always consult a doctor for personal advice.

Yes, completely free with no signup or account required. All calculations run in your browser — your data is never sent to a server. Use it as many times as you want.

Yes. Ideal weight formulas don't account for muscle mass. A muscular person will naturally weigh more than a sedentary person of the same height — and be healthier for it. Combine ideal weight with body fat percentage and lean body mass measurements for a more complete picture of your health.

Aim for a gradual calorie deficit of about 500 calories per day for weight loss (roughly 0.5 kg per week). Prioritize protein at 1.6–2.2g per kg to preserve muscle. Avoid crash diets that cause muscle loss and metabolic slowdown. If underweight, a slight caloric surplus with strength training builds lean mass.