Ideal Weight: How Much Should You Weigh?

"How much should I weigh?" is one of the most common health questions people ask, and it sounds like it should have a single, tidy answer. The truth is more nuanced. The concept of an "ideal weight" can be a helpful reference point, but it was never meant to be a precise prescription for any individual. This guide walks you through where the popular ideal weight formulas come from, how to calculate them, how to interpret the results, and how to set a target that actually fits your body and your life.

What "Ideal Weight" Really Means

The idea of an ideal weight grew out of insurance industry tables in the early twentieth century, when companies wanted to estimate health risk based on height and weight. Over time, clinicians developed simpler formulas to estimate a "reasonable" weight for a given height, originally to help calculate medication dosages rather than to define personal fitness goals.

That history matters because it reveals the biggest limitation of ideal weight: it is a population-level estimate, not a personalized target. The formulas you'll see below were built around averages, and they assume a fairly typical body composition. They don't know whether you're a competitive rower with dense muscle, recovering from illness, or simply built with a wider or narrower frame than average. Treat any "ideal weight" number as a starting conversation, not a verdict.

The Common Ideal Weight Formulas

Several formulas have become standard references. They all use your height above five feet (60 inches) as the main input and differ slightly in their constants. Here are the three most cited.

Devine Formula (1974): Originally created for drug dosing, this is the most widely used.

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

Robinson Formula (1983): A refinement of Devine.

Men: 52 kg + 1.9 kg for each inch over 5 feet
Women: 49 kg + 1.7 kg for each inch over 5 feet

Hamwi Formula (1964): Developed for quick clinical estimates.

Men: 48 kg + 2.7 kg for each inch over 5 feet
Women: 45.5 kg + 2.2 kg for each inch over 5 feet

Notice that these give different answers for the same person. That spread is a feature, not a flaw: it reminds you that "ideal" is a range, not a point.

A Worked Example

Let's calculate the ideal weight for a man who is 5 feet 10 inches tall. That's 10 inches over 5 feet.

Devine: 50 + (2.3 × 10) = 50 + 23 = 73 kg (about 161 lbs)

Robinson: 52 + (1.9 × 10) = 52 + 19 = 71 kg (about 157 lbs)

Hamwi: 48 + (2.7 × 10) = 48 + 27 = 75 kg (about 165 lbs)

So depending on the formula, this man's ideal weight lands somewhere between roughly 71 and 75 kg. Rather than picking one number, you can reasonably treat that whole band as healthy. Running every formula by hand is tedious, so the ideal weight calculator does all three at once and shows you the range instantly.

Ideal Weight Ranges by Height

To give you a quick sense of scale, here are approximate ideal weight ranges (blending the formulas above) for adults. Use these as ballpark figures only.

5'0" (152 cm): roughly 45–52 kg (99–115 lbs)
5'4" (163 cm): roughly 53–60 kg (117–132 lbs)
5'8" (173 cm): roughly 61–69 kg (135–152 lbs)
6'0" (183 cm): roughly 70–80 kg (154–176 lbs)
6'4" (193 cm): roughly 80–91 kg (176–200 lbs)

Men typically sit toward the higher end of a given height band and women toward the lower end, reflecting average differences in build and muscle mass.

Why Frame Size, Muscle, and Age Matter

The formulas above intentionally ignore three big variables, so you have to add them back in yourself.

Frame size. Two people of identical height can have very different bone structures. Someone with broad shoulders and thick wrists will healthily carry more weight than someone with a slight, narrow frame. A common rule of thumb: add about 10% for a large frame and subtract about 10% for a small frame.

Muscle mass. Muscle is denser than fat, so a strength athlete may weigh well above their "ideal" number while carrying very little body fat. In these cases the formula simply doesn't apply, and the scale is the wrong tool entirely.

Age and life stage. Body composition shifts over the years, and a slightly higher weight in older adults can be protective rather than harmful. Pregnancy, recovery from illness, and certain medications also legitimately move the target.

Ideal Weight vs. BMI vs. Body Composition

These three concepts are related but answer different questions.

Ideal weight formulas give you a target weight in pounds or kilograms based on height and sex. They're concrete and easy to act on but blind to body composition.

BMI takes your actual weight and height and sorts you into a category. It's useful for screening across large groups but, like the ideal weight formulas, can't tell muscle from fat. If you want to understand that side of the picture, our BMI guide and calculator explains the categories and their limits.

Body composition measures what your weight is actually made of: the percentage that is fat versus lean mass. This is the most informative of the three, because two people at the same "ideal" weight can have dramatically different amounts of body fat. Tools like skinfold calipers, bioelectrical impedance scales, and DEXA scans estimate this directly.

The practical takeaway: use ideal weight and BMI as quick screens, but lean on body composition and how you feel and perform when you want a real answer.

Setting a Realistic Target

Once you have a sense of your ideal weight range, turn it into a plan you can actually live with.

Aim for a range, not a single number. Your weight naturally fluctuates a kilogram or two day to day from water and food. A range absorbs that noise and reduces frustration.

Adjust for your reality. Factor in your frame size, training, age, and health history. If the formula says 70 kg but you're a heavily muscled lifter sitting comfortably at 78 kg with low body fat, the formula is wrong, not you.

Change slowly. A sustainable rate of weight change is roughly 0.5 to 1 kg (1 to 2 lbs) per week. Faster than that and you risk losing muscle or burning out.

Track more than the scale. Notice your energy, strength, sleep, and how clothes fit. These often reflect progress before the number moves.

Check in with a professional. If you have significant weight to gain or lose, or any underlying health conditions, a doctor or dietitian can tailor a target far better than any formula.

Key Takeaways

• "Ideal weight" is a population-level estimate from old insurance and dosing tables, useful as a reference point but not a personalized prescription

• The Devine, Robinson, and Hamwi formulas each use your height above 5 feet and give slightly different numbers, so treat the spread between them as a healthy range

• Frame size, muscle mass, and age all shift your real target, so adjust the formula's output to fit your individual build

• Ideal weight and BMI are quick screening tools, but body composition (fat versus lean mass) gives the most meaningful picture of your health

• Set a target range rather than a single number, change weight gradually, track non-scale signs of progress, and seek professional guidance for big or medically complex goals