BMI Calculator

Calculate your Body Mass Index. Enter your weight and height to find your BMI and health category instantly.

Your Measurements

Weight

Height

1618.525303540+

Your BMI

24.2

BMI Chart, Healthy Weight Range & Age Group Comparison

See your BMI position on a visual chart, calculate the exact weight range for a healthy BMI, and compare healthy ranges across age groups.

Your BMI: 24.2 — Normal Weight

Healthy Weight Range for 170cm Height

Minimum healthy weight (BMI 18.5)

53.5 kg

Maximum healthy weight (BMI 24.9)

72.0 kg

Midpoint target weight

62.7 kg

Professional

Body Composition, Calorie Needs & Weight Plan

Estimate body fat percentage, waist-to-hip ratio risk, daily caloric needs based on your activity level, and a realistic weight management timeline.

Gender

Age

years

Waist Circumference

Hip Circumference

Estimated Body Fat

19.8%

Waist-to-Hip Ratio

0.842

WHR Risk Level

Low risk

Estimated Body Fat %

19.8%

Fat Mass (est.)

13.8 kg

Lean Mass (est.)

56.2 kg

Body fat estimates are based on formulas and may differ from clinical measurements (DEXA scan, hydrostatic weighing). Use as a guide only.

How to Use This Calculator

Enter your weight in kilograms and your height in centimetres. Your BMI and health category are calculated instantly. The colour-coded scale shows where your BMI falls relative to the standard WHO categories. The calculator also shows your healthy weight range for your specific height.

To convert from other units: multiply pounds by 0.453 for kg; multiply feet by 30.48 for cm; multiply inches by 2.54 for cm.

The Formula

BMI = Weight (kg) ÷ [Height (m)]² Height in metres = Height (cm) ÷ 100 Example: 70 kg, 170 cm Height in m = 170 ÷ 100 = 1.70 m BMI = 70 ÷ (1.70 × 1.70) = 70 ÷ 2.89 = 24.2 Healthy weight range: Minimum = 18.5 × Height² (in m²) Maximum = 24.9 × Height² (in m²)

BMI Categories

Below 16.0Severely Underweight

16.0–18.4Underweight

18.5–24.9Normal Weight (Healthy)

25.0–29.9Overweight

30.0–34.9Obese — Class I

35.0–39.9Obese — Class II

40.0 and aboveObese — Class III (Morbidly Obese)

Example

Ngozi: 68 kg, 163 cm

Height in metres1.63 m

BMI68 ÷ 2.657 = 25.6

CategoryOverweight

Healthy Range49.1–66.2 kg

Weight to Lose~1.8 kg

Ngozi is just slightly over the healthy range. Losing about 2 kg would bring her BMI to 24.9, the upper edge of the normal category. This is a modest and achievable goal through dietary adjustment alone.

BMI Limitations and Nigerian Context

BMI is a useful screening tool but has important limitations:

Muscle mass: BMI does not distinguish between muscle and fat. A muscular person may have a high BMI without excess body fat.
Ethnic variation: Some research suggests that Sub-Saharan African populations may have different health risk thresholds. Nigerian bodies tend to have different fat distribution patterns compared to European populations on which original BMI tables were based.
Age and sex: BMI does not adjust for age or sex differences in body composition. Older adults typically have more body fat than younger adults at the same BMI.
Waist circumference: Many health professionals now recommend checking waist circumference alongside BMI. For Nigerians, waist circumference above 90cm (men) or 80cm (women) increases risk for metabolic syndrome.

BMI is a screening tool, not a diagnostic measure. For a proper health assessment, consult a qualified medical professional. High BMI alone does not constitute a diagnosis.

FAQ

BMI is a reasonable first screening tool but it was originally developed based on European populations. Some studies suggest that people of African descent may experience metabolic health risks at lower BMI thresholds than Europeans, particularly for type 2 diabetes risk. The standard WHO thresholds (18.5–24.9 normal) are still widely used in Nigerian clinical practice but should be interpreted alongside other health markers like blood pressure, blood glucose, and waist circumference.

For a healthy BMI of 18.5–24.9, your healthy weight range depends on your height. For example: 160cm height → 47–64 kg; 170cm → 53–72 kg; 175cm → 57–76 kg; 180cm → 60–81 kg. These are guidelines — individual factors like bone density, muscle mass, and medical conditions all affect what weight is truly healthy for you personally.

Yes, obesity rates are rising rapidly in Nigeria, particularly in urban areas. According to national surveys, overweight and obesity affect approximately 20–35% of adult urban Nigerians, with higher rates among women. Rising processed food consumption, sedentary urban lifestyles, and reduced physical activity are key drivers. The prevalence is higher in Lagos, Abuja, and Port Harcourt than in rural areas.