Free Health Tool

Body Mass Index (BMI) Calculator

Check your BMI to find out if you're a healthy weight for your height. Our calculator uses NHS-recommended ethnic-adjusted thresholds for more accurate results.

Quick & Easy

Calculate your BMI in seconds with metric or imperial units

Ethnic-Adjusted

Thresholds adjusted for different ethnic backgrounds per NHS guidance

Evidence-Based

Based on WHO and NICE clinical guidelines for adults 18+

Calculate Your BMI

Ethnic background(affects thresholds)

Height

Weight

BMI Categories

Underweight< 18.5

Healthy weight18.5 – 25

Overweight25 – 30

Obese (Class I)30 – 35

Obese (Class II)35 – 40

Obese (Class III)40+

Did you know?

BMI doesn't tell the whole story. Waist circumference, body composition, and lifestyle factors all play important roles in your overall health. Our dietitians consider the full picture when creating your personalised plan.

How is BMI Calculated?

The Formula

BMI = weight (kg) ÷ height (m)²

Body Mass Index is calculated by dividing your weight in kilograms by your height in metres squared. It provides a simple numerical measure of your body weight relative to your height.

Example Calculation

1Height: 1.75 m → 1.75 × 1.75 = 3.0625

2Weight: 70 kg

370 ÷ 3.0625 = 22.9 kg/m² (Healthy weight)

Why Ethnic Background Matters

Research shows that health risks linked to excess weight vary across different ethnic groups. The NHS recommends using lower BMI thresholds for certain populations.

Standard Thresholds

White ethnic backgrounds

Healthy weight18.5 – 24.9

Overweight25 – 29.9

Obese30+

Adjusted Thresholds

Asian, African-Caribbean, Black African, Middle Eastern

Healthy weight18.5 – 22.9

Overweight23 – 27.4

Obese27.5+

Weight Management Support at Medocta

Whether you're looking to build healthier habits or need specialist support, we have a programme to help. Here's how it works.

Starting point

12-Week Lifestyle Programme

Build lasting healthy habits with structured support

Personalised nutrition guidance and meal plans
Physical activity support tailored to you
Behaviour change coaching and goal setting
Progress tracking with dietitian check-ins
Culturally sensitive, with multi-language support

Who is it for: Adults 18+ with BMI 30 or above (27.5 for certain ethnic backgrounds)

How to access: Self-refer through Medocta or ask your GP

Or, for more complex needs…

Comprehensive support

Specialist Weight Management

Multidisciplinary care for complex weight management needs

Expert team: dietitians, psychologists, exercise specialists
12-month programme with regular progress reviews
Addresses linked conditions (diabetes, blood pressure, etc.)
Personalised treatment plan for sustainable results
6-month checkpoint to adapt your plan

Who is it for: Adults 18+ with BMI 35+ and related health conditions, or BMI 40+ (thresholds lowered by 2.5 for certain backgrounds)

Related conditions: Type 2 diabetes, hypertension, high cholesterol, cardiovascular disease, asthma, arthritis

How to access: GP referral required

Not sure which programme is right for you? That's completely normal. Book a free consultation and we'll help you find the right path based on your health, goals, and circumstances — no obligation.

Ready to Take the Next Step?

From our 12-week lifestyle programme to specialist weight management, our qualified dietitians and healthcare professionals will guide you every step of the way.

Frequently Asked Questions

Disclaimer: This BMI calculator is provided for informational purposes only and is not a substitute for professional medical advice. BMI is a screening tool and does not diagnose body fatness or health. Always consult a qualified healthcare professional for personalised health assessments. This tool is designed for adults aged 18 and over.