Health & Fitness
Overweight Calculator
Calculate your Body Mass Index (BMI) and determine your weight status category. Get personalized health insights based on your results.
Reviewed by the calculator.uk.com Team · Last reviewed 30 July 2026 · Our methodology
Enter your height and weight to see your BMI results
Related to Overweight Calculator
The Overweight Calculator uses the Body Mass Index (BMI) formula to assess whether a person's weight falls within a healthy range for their height. BMI is calculated by dividing a person's weight in kilograms by their height in meters squared (kg/m²). This calculator supports both metric (centimeters, kilograms) and imperial (inches, pounds) measurements, automatically converting units as needed.
BMI Categories
The World Health Organization (WHO) defines the following BMI ranges: • Underweight: BMI less than 18.5 • Normal weight: BMI 18.5-24.9 • Overweight: BMI 25-29.9 • Obese Class I: BMI 30-34.9 • Obese Class II: BMI 35-39.9 • Obese Class III: BMI 40 or greater
The calculator also determines your healthy weight range based on your height, showing you the weight range that would put your BMI between 18.5 and 24.9, which is considered the normal weight category. This range is calculated using the same BMI formula, solving for weight while using your current height and the target BMI range boundaries.
Your BMI result provides a general indication of whether your weight falls within a healthy range. However, it's important to understand that BMI is just one of many factors in assessing overall health. The calculator provides several key pieces of information to help you interpret your results:
BMI Value and Category
Your calculated BMI number and corresponding category (underweight, normal weight, overweight, or obese) help you understand where your current weight falls on the BMI scale. Each category is associated with different health implications and risks.
Health Risk Assessment
The calculator provides information about potential health risks associated with your BMI category. Being outside the normal weight range (either underweight or overweight) may increase your risk for certain health conditions.
Healthy Weight Range
Based on your height, the calculator shows you the weight range that would put you in the normal BMI category (18.5-24.9). This range can serve as a general guide for weight management goals.
1. Is BMI accurate for everyone?
BMI is a general screening tool but may not be accurate for all individuals. It doesn't account for factors like muscle mass, bone density, age, sex, ethnicity, and body fat distribution. Athletes with high muscle mass, for example, may have a high BMI but not be overweight.
2. How often should I check my BMI?
For most adults, checking BMI once or twice a year is sufficient unless you're actively working on weight management. More frequent monitoring may be needed if you're following a weight loss program or if recommended by your healthcare provider.
3. What should I do if my BMI is outside the normal range?
If your BMI falls outside the normal range, consider consulting with a healthcare provider. They can perform additional assessments and help develop an appropriate plan for your individual situation, which may include dietary changes, physical activity recommendations, or other interventions.
4. Can children use this BMI calculator?
No, this calculator is designed for adults aged 20 and older. Children and teens should use age- and sex-specific BMI calculators, as their normal ranges vary with age and development. Healthcare providers use special growth charts to interpret BMI for young people.
5. What is the scientific source for this calculator?
BMI itself is a two-century-old idea — Adolphe Quetelet first proposed the weight-to-height-squared formula in the 1830s — but the specific cut-off points used here (18.5, 25, 30, 35 and 40 kg/m2) come from the World Health Organization's international classification, set out in WHO Technical Report Series 894, "Obesity: Preventing and Managing the Global Epidemic" (2000), which reviewed population data linking BMI to health outcomes. The same thresholds are used by the NHS and CDC for adult weight screening, though the WHO itself notes they are less reliable for very muscular individuals and can vary in meaning across ethnic groups with different body-fat distributions at a given BMI.