Seven ways to answer "what should I weigh?", including the only one that accounts for muscle.
The weight that people of your sex, age, height and current weight say is their ideal. A realistic goal, not a punishing one. Formula by Dr. Steven B. Halls.
BMI 18.5–24.9 for your height. Your BMI: –
BMI can't tell muscle from fat. If you lift, check the muscle-aware numbers below.
Lean mass – · FFMI –
Keeping that muscle, you'd weigh:
Add your body fat % to see your lean mass, your FFMI, and what you'd weigh leaner with the muscle you already have.
How much you'd weigh at your height with different amounts of muscle (FFMI, normalized to height).
| Muscle level | FFMI | Weight |
|---|
Built for medication dosing, not physiques. Shown for completeness.
| Formula | Ideal weight |
|---|
"Ideal weight" sounds like one number, but every formula answers a different question. This calculator shows them side by side so you can see where they agree and pick a goal that makes sense for you.
This method comes from Dr. Steven B. Halls, whose ideal weight calculator was one of the most-used on the web for nearly two decades (archived copy). Instead of starting from a medical rule, it is fitted to what real people of a given sex, age, height and weight say their ideal weight is. It works by converting your current BMI into a target BMI:
The target BMI is then converted back to a weight for your height. Because it depends on your current weight, the result moves as you do. Enter a lower weight and the "ideal" drops too. That isn't a bug: it mirrors how people's goals shift as they get closer to them. Treat it as a realistic next goal rather than a final destination.
Body mass index is weight in kilograms divided by height in meters squared. The World Health Organization classes a BMI of 18.5–24.9 as normal weight, and the range shown is every weight that falls inside it for your height. It's a solid population-level guide, but it can't tell muscle from fat. Plenty of lifters are "overweight" by BMI while being lean, which is why this page doesn't stop there. For your BMI on its own, with categories and a body fat check, use the BMI calculator.
Fat-free mass index (FFMI) is BMI for muscle: lean mass divided by height squared, adjusted to a reference height of 1.8 m so tall and short people can be compared. If you know your body fat percentage, the calculator shows your current FFMI and what you'd weigh at a lower body fat while keeping the muscle you already have. That number is usually the most useful goal weight for anyone who trains.
The lifter table works the other way: pick a body fat level and it shows what you'd weigh at four levels of muscle. For men, a 1995 study by Kouri and colleagues found that drug-free athletes rarely exceeded an FFMI of about 25, so the top row is close to a natural ceiling. Research on women is thinner, so the female benchmarks are rough estimates. Don't know your body fat? A tape-measure estimate (like the US Navy method) or a smart scale is close enough to use here.
The Devine, Robinson, Miller and Hamwi formulas all take the same shape: a base weight for someone 5 feet tall, plus a fixed amount for every inch above that. They were built to estimate drug doses, not goal physiques, and give the same answer to a bodybuilder and a desk worker of the same height. Dr. Halls suggested Devine for men and Robinson for women if you want one of them.
The scale only tells you part of the story. Tracking what you lift alongside your bodyweight shows whether a change is muscle or fat: if your weight goes up while your lifts climb, you're on the right track. A training log like GymGod keeps both in one place.
There is no single correct ideal weight. The classic formulas (Devine, Robinson, Miller, Hamwi) were designed for medication dosing and ignore body composition. The People's Choice formula reflects what people like you actually consider ideal, and the healthy BMI range shows where health risk is lowest for the general population. If you lift, the FFMI-based numbers are the most meaningful, because they account for muscle.
The People's Choice formula is based on what people at a given weight describe as their ideal. People who weigh more tend to name a higher ideal, so the result moves with your current weight. Dr. Halls described this himself: people are rarely satisfied, and the goal shifts as they get closer to it.
Not very. BMI only uses height and weight, so it can't tell muscle from fat. A muscular lifter can have a BMI over 25 at a low body fat percentage. Use FFMI (fat-free mass index) together with body fat percentage for a better picture.
Fat-free mass index is your lean mass (everything that isn't fat) divided by your height squared, adjusted to a reference height of 1.8 m. It's like BMI, but for muscle. In a 1995 study of male athletes, Kouri and colleagues found that drug-free lifters rarely exceeded an FFMI of about 25.
Dr. Steven B. Halls' popular ideal weight calculator at halls.md/ideal-weight/body.htm is no longer online. This calculator includes his People's Choice formula, credited to him, along with the classic formulas his page showed and a muscle-aware method for lifters.
Free for any website, blog or gym page. Copy and paste this code:
GymGod logs your workouts and bodyweight together, so you can see whether the scale is moving for the right reasons.
