How to Use Our Calculators

BMI Calculator

  1. Choose your preferred unit system (metric or imperial)
  2. Enter your height and weight
  3. Click "Calculate BMI" to see your result
  4. Your BMI score and category will appear with a visual indicator
  5. Optionally, sign in to save your result and track changes over time

For the most accurate results, weigh yourself in the morning before eating, wearing minimal clothing. Try the BMI Calculator →

Body Fat Calculator

  1. Select your gender
  2. Measure and enter your height, waist, and neck circumference in centimetres
  3. If female, also enter your hip circumference
  4. Click "Calculate Body Fat" to see your percentage and category

Use a flexible tape measure. Measure your waist at the navel, your neck just below the larynx, and your hips at the widest point. Try the Body Fat Calculator →

Calorie Calculator

  1. Select your gender and enter your age, height, and weight
  2. Choose your activity level from the dropdown
  3. Click "Calculate Calories" to see your BMR and TDEE
  4. View recommended calories for weight loss, maintenance, and gain

Be honest about your activity level for the most accurate results. Try the Calorie Calculator →

Ideal Weight Calculator

  1. Select your gender and enter your height
  2. Click "Calculate Ideal Weight" to see results from four scientific formulas
  3. The average provides a balanced estimate

Remember that ideal weight varies based on individual factors like muscle mass and frame size. Try the Ideal Weight Calculator →

Waist-to-Hip Ratio Calculator

  1. Measure your waist circumference at the narrowest point (usually just above the navel)
  2. Measure your hip circumference at the widest point of your buttocks
  3. Enter both measurements and select your gender
  4. Click "Calculate" to see your ratio and risk category

Stand relaxed and breathe normally while measuring — do not suck in your stomach. A ratio above 0.85 for women or 0.90 for men indicates higher cardiovascular risk. Learn more in our Heart Health Guide.

Tips for Accurate Measurements

  • Measure at the same time each day for consistency
  • Use calibrated scales and tape measures
  • Stand straight and relaxed when measuring height
  • Take measurements on bare skin for circumference readings
  • Take multiple measurements and use the average

Detailed Measurement Guide

How to Weigh Yourself Properly

For the most reliable weight reading, weigh yourself first thing in the morning after using the bathroom and before eating or drinking. Wear minimal clothing or the same clothing each time. Place your scale on a hard, flat surface — carpet can cause inaccurate readings. Digital scales are generally more accurate than dial scales. Avoid weighing yourself after exercise, as fluid loss can temporarily skew results downward.

How to Measure Your Height Accurately

Remove your shoes and any headwear. Stand against a flat wall with your heels, buttocks, shoulder blades, and the back of your head touching the wall. Look straight ahead so your chin is parallel to the floor. Have someone place a flat object (such as a book) on top of your head, pressing it against the wall, and mark the wall at the bottom edge. Measure from the floor to the mark with a tape measure. Height can vary by up to 2 cm throughout the day due to spinal compression, so measure in the morning for the most consistent result.

How to Take Circumference Measurements

Use a flexible, non-stretchy tape measure (cloth or fibreglass tape measures work well). Pull the tape snug against the skin without compressing it. For waist measurements, wrap the tape around your natural waistline, which is typically the narrowest part of your torso, just above the navel. For neck measurements, measure just below the larynx (Adam's apple) with the tape sloping slightly downward at the front. For hip measurements, stand with feet together and measure at the widest part of your buttocks.

Common Mistakes to Avoid

  • Rounding measurements — enter exact values. Rounding your height up by even 2 cm or your weight down by 1 kg can shift your BMI by a full point.
  • Measuring after meals — food and fluid intake can temporarily add 0.5–2 kg to your weight, giving misleading results.
  • Using the wrong units — double-check that you have selected the correct unit system (metric or imperial) before entering values. Mixing units is one of the most common errors.
  • Holding your breath during circumference measurements — breathe normally. Sucking in your stomach can reduce your waist measurement by several centimetres and give inaccurate body fat estimates.
  • Comparing yourself to a single measurement — body metrics fluctuate daily due to hydration, diet, and activity. Track trends over weeks and months rather than reacting to a single reading.
  • Ignoring the context — a high BMI does not automatically mean poor health if you have significant muscle mass. Combine BMI with body fat percentage and waist circumference for a more accurate assessment.

When to Retest

If you are actively working to change your body composition, retest every two to four weeks. This interval is long enough to see meaningful changes without being so frequent that normal daily fluctuations cause unnecessary stress. Log your results over time to visualise progress — our platform allows you to save and track measurements when you create a free account.

Understanding What Your Results Mean

Numbers alone do not tell the full story. After using any of our calculators, visit the Understanding Your Results page for a detailed guide on interpreting each metric, including what the categories mean, what factors can influence accuracy, and when you should consult a healthcare professional. You can also view our BMI Chart to quickly see where your weight falls relative to healthy ranges for your height.

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