Ideal Weight Calculator

What Should You Weigh?

Ideal body weight isn't a single magic number — it's a range influenced by height, frame size, muscle mass, age, and sex. Our calculator uses four validated medical formulas (Devine, Robinson, Miller, and Hamwi) to provide a range of estimates, giving you a more nuanced target than any single formula alone.

These formulas were originally developed for clinical purposes — primarily calculating medication doses where body weight matters. They've since been adopted as general health references, though none is perfect for every body type. By showing all four results together, our calculator helps you identify the range that applies to your build.

Quick reference: For a 5'10" male, ideal weight estimates range from 149 lbs (Miller) to 166 lbs (Devine). For a 5'5" female, estimates range from 127 lbs (Miller) to 137 lbs (Robinson). The 15–20 lb spread reflects genuine uncertainty — your personal ideal depends on body composition, not just height.

The Four Formulas Explained

Devine Formula (1974) is the most widely used in clinical settings. For men: 50 kg + 2.3 kg per inch over 5 feet. For women: 45.5 kg + 2.3 kg per inch over 5 feet. Originally created for drug dosing calculations in anesthesia, it tends to produce lower estimates for taller individuals and higher estimates for shorter ones. Despite its age, it remains the default in most medical software.

Robinson Formula (1983) was designed to improve on Devine's estimates. For men: 52 kg + 1.9 kg per inch over 5 feet. For women: 49 kg + 1.7 kg per inch over 5 feet. It produces slightly higher estimates than Devine for shorter people and lower for taller people, reflecting updated population data from the early 1980s.

Miller Formula (1983) uses a different baseline. For men: 56.2 kg + 1.41 kg per inch over 5 feet. For women: 53.1 kg + 1.36 kg per inch over 5 feet. It tends to produce the lowest estimates overall and is best suited for people with smaller frames. Its lower per-inch increment means it diverges less between short and tall individuals.

Hamwi Formula (1964) is the oldest of the four. For men: 48 kg + 2.7 kg per inch over 5 feet. For women: 45.5 kg + 2.2 kg per inch over 5 feet. It tends to produce the highest estimates and may be most appropriate for people with larger frames. Its steeper per-inch slope means it gives substantially higher targets for tall individuals.

Which formula is "right"? None — and all. Each was derived from different population samples with different methodologies. The best approach is to look at the range across all four and consider where you fall based on your frame size and build.

Frame Size: Why It Matters

All four formulas can be adjusted ±10% for frame size. A small-framed person should look at the lower end of the range; a large-framed person at the upper end. This adjustment can shift the target by 15–20 lbs, which is clinically significant.

How to measure your frame: Wrap your thumb and middle finger around your wrist at the narrowest point (just below the wrist bone). If they overlap, you have a small frame. If they just touch, medium frame. If there's a gap, large frame.

More precise method: Measure your wrist circumference with a tape measure. For women 5'2"–5'5": small frame is under 6", medium is 6"–6.25", large is over 6.25". For men over 5'5": small is under 6.5", medium is 6.5"–7.5", large is over 7.5".

Frame size reflects skeletal structure — larger bones and joints naturally support more tissue. A large-framed man at 5'10" might have an ideal weight range of 165–183 lbs, while a small-framed man of the same height might target 135–150 lbs. Ignoring frame size can lead to unrealistic targets that are either too low (causing unnecessary restriction) or too high (masking genuine excess weight).

Why Ideal Weight Is a Range, Not a Number

No formula accounts for muscle mass, bone density, body fat distribution, or ethnic variation in body composition. A 5'10" man with significant muscle mass may weigh 185 lbs at 12% body fat — well above all formula estimates but extremely healthy by every metabolic marker. Conversely, a sedentary person at 166 lbs might carry 30% body fat despite being at "ideal weight" by the Devine formula.

This is the fundamental limitation of height-weight formulas: they predict what a person of average body composition should weigh, but individual body composition varies enormously. Two people at the same height and weight can have radically different health profiles depending on how much of that weight is muscle versus fat.

For this reason, ideal weight formulas work best as starting references — particularly for people who aren't sure what range to target. Once you have a starting reference, refine it with body fat percentage measurement, waist circumference (a waist above 40" for men or 35" for women indicates elevated health risk regardless of total weight), and health markers (blood pressure, blood sugar, cholesterol, triglycerides).

The healthiest weight for you is the one where your metabolic markers are in a healthy range, you have energy for daily activities and exercise, you can maintain it without extreme dietary restriction, and you're not experiencing weight-related joint pain, sleep apnea, or other physical issues.

Ideal Weight Across Different Populations

These formulas were developed primarily from data on white American and European populations, and they may not apply equally to all ethnic groups. Research shows that body composition at the same BMI and weight varies across populations.

Asian populations tend to have higher body fat percentages at lower weights compared to white populations. The WHO has suggested lower BMI cutoffs for overweight (23 vs. 25) and obese (27.5 vs. 30) in Asian populations. Ideal weight targets from these formulas may be slightly too high for Asian individuals.

Black populations tend to have higher bone density and muscle mass at the same height, meaning ideal weight targets from these formulas may be slightly too low. Studies show that Black individuals often have lower body fat at the same BMI compared to white individuals.

Hispanic populations show intermediate patterns, with body composition that falls between Asian and white reference populations at the same BMI.

These are population-level tendencies, not individual rules. Your personal body composition matters far more than population averages. Use the formulas as a starting point and refine based on your actual health metrics.

Using Ideal Weight for Goal Setting

If you're currently above the ideal weight range and want to lose weight, the formula range gives you a realistic long-term target. However, set intermediate goals — losing 5–10% of current body weight produces significant health improvements even before reaching "ideal weight." A 220 lb person who loses 22 lbs (to 198) will see meaningful improvements in blood pressure, blood sugar, cholesterol, joint pain, and energy levels.

If you're within the ideal range, focus on body composition rather than the number on the scale. Replacing 5 lbs of fat with 5 lbs of muscle doesn't change your weight but dramatically improves your appearance, metabolic health, and functional capacity.

If you're below the ideal weight range, ensure you're getting adequate nutrition. Being underweight is associated with increased health risks including weakened immune function, bone density loss, hormonal disruption, and reduced muscle mass. Consult a healthcare provider if you're significantly below the range — especially if you've experienced unintentional weight loss.