Ideal Weight Calculator
Find your ideal body weight using multiple scientific formulas. Get a personalized weight range based on your height, gender, and body frame.
Ideal Weight Calculator
What Is Ideal Body Weight?
Ideal body weight (IBW) is the weight range associated with the best health outcomes for your height, gender, and body type. Unlike BMI categories, ideal weight gives you a specific target to work towards.
Multiple Scientific Formulas
We use 4 established formulas (Devine, Robinson, Miller, Hamwi) to calculate your ideal weight range. Each formula uses slightly different assumptions, giving you a more complete picture than any single calculation.
Body Frame Matters
People with larger frames naturally weigh more at the same height. Measure your wrist or elbow breadth to determine your frame size, or use "medium" as a default for average builds.
Healthy Weight Range
Your ideal weight is a range, not a single number. Focus on where you feel your best - with good energy, comfortable movement, and no health issues - rather than an exact figure.
⚠️ These formulas don't account for muscle mass. Athletes and muscular individuals may have ideal weights higher than calculated. Consider body fat percentage for a more complete assessment.
The Formulas We Use
This calculator uses four well-established ideal weight formulas. Here's how each one works:
Devine Formula (1974)
The most commonly used formula in medical settings, originally developed for calculating drug dosages.
- 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
This formula tends to give lower ideal weights and works best for people with medium frames.
Robinson Formula (1983)
A modification of the Devine formula that gives slightly higher ideal weights.
- Men: 52 kg + 1.9 kg for each inch over 5 feet
- Women: 49 kg + 1.7 kg for each inch over 5 feet
Miller Formula (1983)
Developed around the same time as Robinson, tends to give the highest ideal weights of the four formulas.
- Men: 56.2 kg + 1.41 kg for each inch over 5 feet
- Women: 53.1 kg + 1.36 kg for each inch over 5 feet
Hamwi Formula (1964)
One of the older formulas, still widely used in nutrition counseling.
- 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
Why the difference? These formulas were developed at different times, using different populations. None is definitively "better" than the others. We recommend looking at the range rather than fixating on any single number.
How Body Frame Size Affects Your Ideal Weight
Your skeletal frame size matters! Someone with broad shoulders and large bones will naturally weigh more than someone with a petite frame, even at the same height and body fat percentage.
How to Determine Your Frame Size
The simplest method is the wrist measurement:
For Women:
- Wrist under 5.5 inches (14 cm) = Small frame
- Wrist 5.5 to 6.5 inches (14-16.5 cm) = Medium frame
- Wrist over 6.5 inches (16.5 cm) = Large frame
For Men:
- Wrist under 6.5 inches (16.5 cm) = Small frame
- Wrist 6.5 to 7.5 inches (16.5-19 cm) = Medium frame
- Wrist over 7.5 inches (19 cm) = Large frame
Frame Size Adjustments:
- Small frame: Subtract 10% from calculated ideal weight
- Medium frame: Use calculated weight as-is
- Large frame: Add 10% to calculated ideal weight
Ideal Weight vs. BMI: What's the Difference?
Both tools help you understand healthy weight, but they work differently:
| Ideal Weight | BMI |
|---|---|
| Gives you a target weight in kg/lbs | Gives you a category (underweight, normal, overweight, obese) |
| Based on height and gender | Based on height and current weight |
| Multiple formulas give different answers | One standard formula worldwide |
| Can account for body frame size | Doesn't consider body composition |
| Useful for setting weight goals | Useful for health risk assessment |
Which should you use? Both! Use BMI to understand where you currently stand, and ideal weight to set a realistic goal. Your ideal weight should fall within the BMI 18.5-24.9 range for optimal health.
Limitations of Ideal Weight Calculations
Before you take your results too seriously, understand what these formulas can't account for:
- Muscle mass: Muscular individuals will have higher "ideal" weights than these formulas suggest
- Age: Older adults may have different optimal weights than younger adults
- Ethnicity: Body composition varies across different ethnic backgrounds
- Health conditions: Various medical conditions affect optimal weight
- Athletic status: Athletes often weigh more than average due to muscle mass
- Individual variation: Two people with identical heights can have very different healthy weights
The Bottom Line: Use your calculated ideal weight as a starting point for discussion with your healthcare provider, not as an absolute target. Your actual ideal weight might be 10-15% different from any formula's prediction.
Setting Realistic Weight Goals
If you're trying to reach your ideal weight, here's how to approach it sensibly:
If You Need to Lose Weight
- Aim to lose 0.5-1 kg (1-2 lbs) per week - this is safe and sustainable
- Set intermediate goals every 5-10 kg rather than focusing only on the final target
- Losing even 5-10% of your current weight has significant health benefits
- Don't crash diet - extreme restriction leads to muscle loss and rebound weight gain
If You Need to Gain Weight
- Aim to gain 0.25-0.5 kg (0.5-1 lb) per week to minimize fat gain
- Focus on protein-rich foods and strength training
- Eat more frequently rather than trying to eat huge meals
- Add healthy calorie-dense foods like nuts, oils, and avocados
If You're Already at Ideal Weight
- Maintain your current eating and exercise habits
- Weigh yourself monthly to catch any trends early
- Focus on body composition - building muscle while maintaining weight is still improving
Frequently Asked Questions
Which ideal weight formula is most accurate?
None is definitively "best." The Devine formula is most commonly used in medical settings, but the Miller formula may be more realistic for many people. Look at the range provided by all formulas rather than picking just one.
Why is my ideal weight different for each formula?
Each formula was developed using different research populations and methodologies. The variation between formulas reflects the reality that there's a range of healthy weights rather than one perfect number.
Can ideal weight be too low?
Yes, especially for tall individuals. Some formulas predict unrealistically low weights for people over 6 feet tall. If your calculated ideal weight would give you a BMI under 18.5, it's probably too low.
Does age affect ideal weight?
These formulas don't account for age, but research suggests older adults may be healthier at slightly higher weights than younger adults. If you're over 65, consider adding 5-10% to your calculated ideal weight.
Should I aim for the lowest number in my ideal weight range?
Not necessarily! The middle of the range is often more realistic and sustainable. Being at the lower end of your ideal weight range may be harder to maintain and not provide any additional health benefits.