BMI & Ideal Weight Calculator

Calculate your Body Mass Index instantly. Discover your healthy weight range and track exactly how much you need to lose or gain to reach your goal.

Height (cm)

Weight (kg)

Saved Records

🔒 Processed entirely in your browser. Zero uploads, zero tracking.

How to Use the BMI Calculator

Choose your Unit System: Toggle between Metric (cm, kg) or Imperial (feet, lbs) using the tabs at the top.
Enter your Details: Input your current height and weight into the fields.
Calculate & Review: Click "Calculate BMI" to instantly reveal your exact BMI score and which health category you fall into.
Analyze Insights: The tool will show your personal "Healthy Weight Range" and calculate exactly how much weight you need to lose or gain to reach it.
Save State: Click "Save to History" to log your current weight into the local browser history to track your progress over time.

BMI Categories Explained

🔵 Underweight (Below 18.5)May indicate insufficient body weight for your height. Gaining weight may be recommended by a healthcare provider.

🟢 Normal Weight (18.5 - 24.9)Considered the optimal healthy weight range for most average adults.

🟠 Overweight (25.0 - 29.9)Slight excess weight. This may be a risk factor for some health conditions, depending on your body composition.

🔴 Obese (30.0 and above)Excess body weight strongly associated with higher risks of cardiovascular issues and other health complications.

How is BMI Actually Calculated?

Body Mass Index (BMI) is a simple mathematical ratio that compares your weight to your height. The standard scientific formula is:

BMI = weight (kg) / [height (m)]²

For the Imperial system, a multiplier is applied:

BMI = (weight in lbs × 703) / [height (inches)]²

Why Choose Our Calculator?

✅ Target Weight Calculation — Don't just get a number; find out exactly how many kilograms or pounds you need to gain or lose to hit the "Normal" category.
✅ 100% Client-Side Privacy — Your health data is sensitive. This tool processes your inputs entirely within your browser memory. Nothing is tracked.
✅ Accurate Scale Bar — Our visual scale bar is mathematically calibrated to accurately plot your position across the true BMI spectrum.
✅ Progress Tracking — Use the History sidebar to locally save your entries over weeks or months to see your BMI drop visually.

Frequently Asked Questions

Is BMI perfectly accurate for everyone?

No. BMI is a population-level screening tool, not a direct measure of body fat percentage. It cannot distinguish between fat and muscle mass. Therefore, muscular athletes may register as "Overweight" or "Obese" despite having very low body fat.

Should children use this BMI calculator?

No. This standard calculator is designed specifically for adults aged 18 and over. Children and teens require a different percentile-based BMI scale that accounts for age and sex during their growth phases.

What is a "Healthy" BMI?

The World Health Organization (WHO) defines a healthy BMI range as 18.5 to 24.9 for the average adult. However, individual health factors, genetics, and frame size should be discussed with a doctor.

Is my data saved or uploaded?

Absolutely not. We have no databases connected to this tool. If you use the "Save to History" feature, it saves the data to your browser's local cache (localStorage) which only you can access.