⚖️ BMI Calculator
Enter your weight and height to see your Body Mass Index and which category it falls into — a quick fitness screening check, whether you're training on land or out on the water.
🧮 Calculate Your BMI
What is a BMI Calculator?
Body Mass Index (BMI) is a quick screening measure that relates your weight to your height, giving a general sense of whether you sit in the underweight, normal, overweight, or obese range. Enter your numbers in metric or imperial units and get an instant result.
It's a useful starting point, not a full picture. BMI can't tell muscle from fat, so sailors, rowers, and other athletes with a muscular, low-body-fat frame often read higher than their actual fitness would suggest. Use it as a general guide and pair it with other measures — waist circumference, body-fat percentage, or a trainer's assessment — for a fuller view of your health.
❓ Frequently Asked Questions
How does the BMI calculator work?
Enter your weight and height in either metric (kg, cm) or imperial (lb, in) units. It divides your weight in kilograms by the square of your height in metres to get your Body Mass Index, then places that number into one of four bands: Underweight, Normal, Overweight, or Obese.
What do the BMI categories mean?
A BMI under 18.5 is classed as Underweight, 18.5–24.9 as Normal, 25–29.9 as Overweight, and 30 or above as Obese. These bands are the standard World Health Organization thresholds used as a general population-level screening tool, not an individual diagnosis.
Is BMI accurate for muscular athletes or sailors?
Not always. BMI only accounts for total weight relative to height — it can't distinguish muscle from fat. Sailors, rowers, and other athletes with above-average muscle mass and a lean frame often score "Overweight" or higher on BMI despite having low body fat. In those cases, waist circumference, body-fat percentage, or a trainer's assessment give a more accurate picture.
Is this medical advice?
No. This tool gives a general fitness estimate for informational purposes only. It doesn't replace a doctor's assessment, and factors like age, sex, bone density, and muscle mass all affect how meaningful a given BMI is for you. Speak to a doctor or qualified trainer for individual guidance.