How Much Should I Weigh? 4 Ideal Weight Formulas Explained

"How much should I weigh?" is one of the most searched health questions in the world — and for good reason. Whether you're setting a weight loss goal or just curious, you want a number to aim for.

The honest answer: there's no single magic number. But there are well-established formulas that give you a realistic target — and when you compare them together, a clear healthy range emerges. Let's break them all down.

Why There's No Single "Ideal" Weight

Your healthy weight depends on much more than height. Two people of the same height can have very different healthy weights because of:

• Body frame size — bone structure varies naturally between people
• Muscle mass — muscle is denser than fat, so muscular people weigh more
• Age — healthy weight ranges shift slightly as we get older
• Sex — men typically carry more muscle and bone mass than women
• Body composition — where you carry weight matters more than the total

That's why researchers created formulas instead of fixed numbers — each one estimates a reasonable target based on your height and sex. None is perfect, but together they triangulate a sensible range.

The 4 Classic Ideal Weight Formulas

All four formulas below start with a base weight at 5 feet (152.4 cm), then add weight for every inch above that. They're designed for adults aged 18 and over.

1. Devine Formula (1974) — The Most Widely Used

2. Robinson Formula (1983)

3. Miller Formula (1983)

4. Hamwi Formula (1964)

Under 5 feet tall? Subtract 2.3 kg per inch below 5 feet from the base weight (using the Devine approach).

The Healthy BMI Range Method

Instead of one number, this method gives you a range — which most experts consider more realistic. It uses the healthy BMI band of 18.5 to 24.9:

Notice something interesting? The four formulas for a 5'9" man all land between 69–72 kg — comfortably inside this healthy band. That's a good sign the methods agree with each other.

Side-by-Side Comparison: All 5 Methods

Here's every method calculated for a 5'9" (175 cm) man:

The takeaway: The four formulas cluster within about 3 kg of each other (~69–72 kg). Their average — around 70 kg — is your best single estimate, and the BMI range gives you flexible upper and lower boundaries.

Frame size adjustment: Hamwi's original guidance suggests subtracting 10% for a small frame or adding 10% for a large frame. A quick frame test: wrap your thumb and middle finger around your wrist. If they overlap, you likely have a small frame; if they don't touch, a larger one.

What These Formulas Miss

Ideal weight formulas are useful starting points — but they have real blind spots:

• They ignore muscle mass. A muscular 5'9" athlete might weigh 80 kg with low body fat and be far healthier than a sedentary person at 68 kg. Check your body fat percentage for the fuller picture.
• They ignore age. Research suggests slightly higher weights may be protective for adults over 65 — these formulas assume younger adults.
• They ignore fat distribution. Belly fat (visceral fat) is far riskier than fat stored elsewhere. Waist circumference often predicts health better than total weight.
• They were built on limited populations. Most were developed decades ago using specific groups, so they may fit some ethnicities and body types better than others — a limitation BMI shares too.

A Better Way to Find Your Healthy Weight

Instead of chasing one number, use this layered approach:

1. Start with the healthy BMI range. It gives you realistic upper and lower boundaries for your height.
2. Use the 4 formulas as a midpoint guide. Their average tells you roughly where in that range a typical build lands.
3. Check your waist. Under 40 inches (102 cm) for men and under 35 inches (88 cm) for women is the general target.
4. Factor in body composition. If you train with weights, lean on body fat percentage rather than scale weight.
5. Listen to performance and energy. Blood pressure, blood sugar, stamina, and how you feel day to day matter more than any formula.

And if your goal is moving toward a healthier weight, the mechanics are simple: understand your TDEE, create a sensible calorie gap, and eat enough protein. Our weight loss guide walks through the whole process. For a height-by-height breakdown of healthy ranges, see our height weight chart.

Frequently Asked Questions