Ideal Weight Calculator

Your ideal weight represents the healthy body-mass range for your height — where you’re neither underweight nor carrying excess fat that may increase health risks. Our Ideal Weight Calculator estimates this range using BMI standards (18.5–24.9) and four scientific formulas — Devine, Hamwi, Robinson, and Miller — widely used by clinicians and researchers. It’s a fast, science-based way to set realistic goals for weight management, fitness, or body-composition planning.

At FreeFitnessCalculators, every tool connects data with action. Along with this calculator, explore BMI, Body Fat %, BMR, TDEE, and Macro calculators to build a personalized, evidence-based health profile.

How to Use the Ideal Weight Calculator

Select your unit system – Metric (cm) or US (ft / in).
Enter your age and gender (for context).
Input your height.
Click Calculate.

Instantly you’ll see:

Your healthy weight range based on BMI 18.5–24.9.
Results from Robinson, Miller, Devine, and Hamwi formulas.
Range width and gender context summary.
Easy share / save / email options for tracking or consultation.

Everything calculates locally — no data stored or sent anywhere.

What Is Ideal Weight?

“Ideal weight” is the weight range statistically linked with lowest risk of chronic disease and optimal energy efficiency. It’s not a single perfect number — it’s a span where body-composition, cardiovascular health, and musculoskeletal balance align for most adults.

The concept evolved from life-insurance and public-health research. Today, medical guidelines use BMI 18.5–24.9 kg/m² as the reference interval. More advanced assessments, like Body Fat % or Waist-to-Hip Ratio, refine interpretation but BMI remains a practical global standard.

BMI-Based Healthy Weight Range

For a given height (h in m), the healthy range is calculated using:

Min Weight = 18.5 × h²
Max Weight = 24.9 × h²

Example: Height = 1.70 m → Healthy Range = 53.5 – 72.0 kg. This approach matches the World Health Organization (WHO) recommendation for adults (18–65 yrs).

Tip: Stay aware that BMI doesn’t distinguish between muscle and fat — athletes may exceed 24.9 yet remain lean and healthy.

Ideal Weight Formulas

Below are the most common predictive equations — they differ by how they treat height and sex, providing slightly different results.

Formula	Equation (kg)	Primary Use
Devine (1974)	50 + 2.3 × (height in in – 60)	Clinical drug dosing
Hamwi (1964)	48 + 2.7 × (height in in – 60)	Frame size estimation
Robinson (1983)	52 + 1.9 × (height in in – 60)	Modern average reference
Miller (1983)	56.2 + 1.41 × (height in in – 60)	Leaner body profiles

For women, the constants are slightly lower (45.5 or 49 instead of 50 / 52 / 56.2). All assume an average frame and healthy lean-to-fat ratio.

Note: These equations use height in inches and output kg after conversion. Variations within 2 – 3 kg between methods are normal.

Comparing Methods & Accuracy

Each formula was developed for a different purpose and population. The Devine and Hamwi equations originated in clinical settings for drug dosage, while Robinson and Miller adjust for modern anthropometric data. Most users will find their results cluster within a 4–6 kg band.

The BMI-based range is best for population-level risk assessment; the formulas provide individualized reference points useful for setting body-composition goals or monitoring progress alongside our Body Fat Calculator.

Factors Affecting Ideal Weight

Body Composition : Muscle vs fat ratio changes weight without changing health.
Age : Lean mass declines with age, lowering energy needs.
Sex : Women naturally carry higher essential fat levels.
Frame Size & Genetics : Bone structure affects visual build.
Lifestyle : Training, sleep, and diet can shift the optimal zone.
Ethnicity : Some populations show different BMI–fat relationships.

Because of these factors, the calculator should guide, not dictate, your goal weight.

How to Interpret Your Results

Below Range : Possible underweight or low muscle mass — evaluate nutrition and strength training.
Within Range : Healthy balance of mass and height; maintain via stable habits.
Above Range : Weight loss may reduce cardio-metabolic risk; track calories using our TDEE Calculator.

Always combine numerical results with subjective metrics — energy levels, strength, and waist circumference (see Waist-to-Hip Ratio).

Maintaining a Healthy Weight

1. Balanced Nutrition

Prioritize whole foods — vegetables, lean proteins, whole grains.
Match calorie intake to your TDEE or goal deficit/surplus.
Use the Macro Calculator to set protein / carb / fat targets.

2. Consistent Activity

Follow WHO guidelines: 150 min of moderate or 75 min vigorous exercise per week.
Combine cardio with strength training to preserve lean mass.

3. Monitor & Adjust

Track weight trends every 2–4 weeks rather than daily fluctuations.
Recalculate ideal weight after significant body-composition changes.

Quick Insight: Muscle is denser than fat — you may gain scale weight while getting leaner. Use body fat % or photos to verify progress.

Frequently Asked Questions

Is there a single “perfect” weight for my height?

No — healthy ranges span around ±10 % of median values. Focus on consistency and body composition rather than one number.

Why do different formulas give different results?

Each formula was derived from unique study samples and assumptions. Small variations (2–5 kg) are normal and not clinically significant.

Does age change my ideal weight?

Yes. Metabolism and muscle mass decline with age, shifting the upper healthy limit slightly downward.

Should I use BMI or body fat % to set goals?

Use BMI for population reference, but combine it with our Body Fat Calculator for precision.

Are these calculations accurate for athletes?

Athletes with high muscle mass often appear “overweight” by BMI but remain very healthy. Use lean-mass-adjusted formulas or DEXA scans for accuracy.

Is this calculator for children?

No. Children and teens should use age-specific BMI percentile charts from the CDC or WHO.

What if my ideal weight feels too low?

Focus on function and energy, not just numbers. Discuss goals with a health professional if your target seems unrealistic.

References & Further Reading

Data and equations are for informational purposes and not a substitute for medical advice.

Conclusion

Your ideal weight isn’t a static number — it’s a dynamic range reflecting balance between health, strength, and well-being. Use this calculator as a scientific guide to understand where you stand and how small, consistent actions can move you toward your healthiest self.

Combine insights from this tool with the TDEE, Macro, and Body Fat calculators for a complete picture of your nutrition and composition goals.

At FreeFitnessCalculators.com, we turn data into direction — helping you make confident, evidence-based choices for lifelong health.