Ideal Body Weight Calculator: What Should You Weigh?
What is ideal body weight?
Ideal body weight is an estimate of the weight range associated with good health and low disease risk for your height and sex. No single number is ideal for everyone because muscle mass, bone density, age, and genetics all affect what a healthy weight looks like. Use the calculator below to see what multiple evidence-based formulas suggest, and use that range as context rather than as a fixed target.
Table of Contents
Ideal Body Weight Calculator
Ideal Body Weight Calculator
What Is Ideal Body Weight and Where Does It Come From?
The concept of ideal body weight originated in the insurance industry in the early 20th century, when actuarial data showed that certain weight ranges relative to height were associated with lower mortality risk. Physicians later adapted these tables for clinical use, and several formulas were developed to produce a quick single-number estimate.
The most widely cited formulas are the Devine formula, developed in 1974 originally for drug dosing calculations, and the Hamwi formula, which has been used in clinical nutrition since the 1960s. Others include the Robinson formula and the Miller formula, all of which produce slightly different outputs for the same height and sex.
What all of these formulas share is that they were developed from population data and produce population averages. They do not account for muscle mass, bone density, age, ethnicity, or the wide variation in body composition that exists among people of the same height. A highly muscular person of a given height may weigh significantly more than the formula's output while having excellent health markers, while someone at the formula's target weight with high body fat and low muscle may have poor metabolic health.
Which Ideal Body Weight Formula Is Most Accurate?
A 2016 analysis published in the Annals of Pharmacotherapy compared multiple IBW formulas against body composition data and found that no single formula was consistently more accurate than the others across all height and sex groups. The authors recommended using a range from multiple formulas rather than relying on any single estimate.
This is why the calculator above shows four formula outputs alongside the healthy BMI weight range: the most useful approach is to look at where these estimates cluster and use that cluster as context for a realistic goal weight, rather than treating any individual number as a precise target.
For most adults of average muscularity, the healthy BMI range of 18.5 to 24.9 provides a more clinically relevant weight goal than any individual IBW formula, since it is derived from population health outcome data rather than from height-to-weight ratios alone.
Why Is BMI Not the Same as Ideal Body Weight?
Body Mass Index is a ratio of weight to height squared, used to screen populations for potential weight-related health risks. The healthy BMI range of 18.5 to 24.9 translates to a range of weights for any given height, which spans from the lower end of healthy to the upper end.
IBW formulas, by contrast, typically produce a single target number rather than a range, and most land somewhere within the healthy BMI band for people of average muscularity.
Neither BMI nor IBW formulas account for body composition. A person with 35 percent body fat may sit in the healthy BMI range while having a metabolic risk profile consistent with higher body fat. Conversely, an athlete with 12 percent body fat may have a BMI in the overweight range while being healthier than population averages on virtually every measurable marker.
For practical goal-setting, the healthy BMI weight range is more useful than a single IBW number, and body fat percentage alongside weight gives the most complete picture.
What Should You Actually Aim For?
Rather than fixating on a specific number from an IBW formula, most sports medicine and nutrition researchers now recommend focusing on a weight range associated with good energy levels, health markers, and sustainable daily function.
Practically, this means aiming for a weight where you feel energetic, where blood pressure, blood glucose, and lipid markers are within healthy ranges, and where maintaining the weight does not require extreme dietary restriction. For most people this sits somewhere within the healthy BMI range, but the exact point within that range depends on individual body composition.
Setting a goal weight from the calculator above gives you a useful starting reference, but treat it as a direction rather than a fixed destination. Body composition, measured through body fat percentage alongside weight, gives a more complete picture of progress than weight alone.
How Do You Track Progress Toward Your Ideal Weight?
Once you have a goal weight from the calculator, the practical work is building a consistent calorie deficit to reach it. Welling sets a personalised daily calorie target based on your goal weight, current stats, and activity level, and logs meals in 2.6 seconds on average through photo, chat, or voice.
The AI nutrition coach tracks your progress daily and weekly, showing how you are moving toward your goal weight and adjusting guidance based on what you actually eat each day. Wearable integration adjusts your calorie budget from workout data automatically.
Track your progress toward your goal weight on Welling
Set your goal weight. Track toward it every day.
Welling logs meals from a photo, chat, or voice note in 2.6 seconds on average and coaches you daily on what to eat to reach your goal weight sustainably.
Frequently Asked Questions
Is ideal body weight the same as goal weight?
Not necessarily. Ideal body weight from formulas is a population-average estimate based on height and sex. Your personal goal weight may differ based on your muscle mass, frame size, and what weight you feel and perform best at. Use IBW formulas as a starting reference, not as an absolute target.
What is the most accurate ideal body weight formula?
No single IBW formula is consistently more accurate than others across all populations. A 2016 review in the Annals of Pharmacotherapy found meaningful variation between formulas and recommended using a range rather than any single estimate. The healthy BMI weight range is often more clinically useful as a goal.
What if my goal weight is below the healthy range?
Goal weights below BMI 18.5 are associated with increased health risks including reduced bone density, hormonal disruption, immune dysfunction, and cardiovascular changes. If you are considering a goal weight below the healthy BMI range, speaking with a healthcare provider or registered dietitian before pursuing that target is strongly recommended.
How long does it take to reach ideal body weight?
This depends on your current weight, goal weight, and daily calorie deficit. Use the weight loss timeline calculator to get a personalised projection. At 0.5 kg per week, every 10 kg of loss takes approximately 20 weeks.
Does ideal body weight change with age?
Some research suggests that slightly higher body weights within the healthy BMI range are associated with better outcomes in older adults, particularly above age 65, where some additional weight may protect against muscle loss and fragility. The standard IBW formulas do not adjust for age, so older adults should discuss appropriate weight goals with their healthcare provider.
What is more important, reaching ideal weight or improving body composition?
For most health outcomes, body composition, the proportion of lean muscle to fat, matters more than hitting a specific weight. Two people at the same weight can have very different health profiles depending on their body composition. Tracking weight alongside body fat percentage gives a more complete picture than weight alone.
References
Devine, B. J. (1974). Gentamicin Therapy. Drug Intelligence and Clinical Pharmacy, 8, 650-655.
Peterson, C. M., Thomas, D. M., Blackburn, G. L., & Heymsfield, S. B. (2016). Universal Equation for Estimating Ideal Body Weight and Body Weight at Any BMI. American Journal of Clinical Nutrition, 103(5), 1197-1203. https://pubmed.ncbi.nlm.nih.gov/26960445/
Pai, M. P., & Paloucek, F. P. (2000). The Origin of the 'Ideal' Body Weight Equations. Annals of Pharmacotherapy, 34(9), 1066-1069. https://pubmed.ncbi.nlm.nih.gov/10981254/
World Health Organization. (2004). Appropriate Body-Mass Index for Asian Populations and Its Implications for Policy and Intervention Strategies. The Lancet, 363(9403), 157-163. https://pubmed.ncbi.nlm.nih.gov/14726171/
Flegal, K. M., et al. (2013). Association of All-Cause Mortality with Overweight and Obesity. JAMA, 309(1), 71-82. https://pubmed.ncbi.nlm.nih.gov/23280227/
Hall, K. D., & Guo, J. (2017). Obesity Energetics: Body Weight Regulation and the Effects of Diet Composition. Gastroenterology, 152(7), 1718-1727. https://pubmed.ncbi.nlm.nih.gov/28193517/
