The UK's most complete GLP-1 guide
Every Question Answered. Every Side Effect Explained.
- How GLP-1 medications work
- Mounjaro vs Wegovy compared
- Injection instructions
- Side effects & solutions
- What to eat on treatment
- FAQs answered
Free tracker included with every download this week
BMI Score Table — NHS Categories Explained
A BMI score table shows where your weight falls within the NHS health categories — from underweight through to severely obese. Your BMI (body mass index) is a simple screening tool that compares your weight to your height. Understanding your BMI score helps you see whether you're in a healthy weight range and can guide conversations with your GP about weight-related health. Use our free BMI calculator above to find your exact score instantly, then see where it sits in the official NHS categories below.
10,000+ calculations today · NHS-aligned thresholds · 100% free
Calculate Your BMI Instantly
Enter your height and weight below. Supports both imperial (stone & lbs) and metric (kg). Results include NHS category, healthy weight range, and ethnicity adjustments.
What Is BMI and Why Does It Matter?
Body Mass Index (BMI) is the most widely used screening tool for assessing whether your weight falls within a healthy range. Used by the NHS, GPs, and weight management services across the UK, BMI provides a quick snapshot of your weight relative to your height. The formula is simple: your weight in kilograms divided by your height in metres squared (kg/m²).
While BMI isn't a perfect measure — it doesn't account for muscle mass, bone density, or fat distribution — it remains the standard first step in identifying potential weight-related health risks including type 2 diabetes, cardiovascular disease, high blood pressure, and certain cancers.
The NHS also recommends adjusted thresholds for people of South Asian, Chinese, or Black African heritage — a BMI of 23 or above is classified as overweight, and 27.5 as obese. Our calculator includes this adjustment as a one-click toggle.
NHS BMI Categories and Healthy Weight Ranges
The NHS BMI formula divides your weight in kilograms by your height in metres squared. Your result falls into one of five main categories:
- Underweight: BMI below 18.5 — may indicate insufficient nutrition or an underlying health issue
- Healthy weight: BMI 18.5–24.9 — associated with lower risk of weight-related diseases
- Overweight: BMI 25.0–29.9 — increased risk of type 2 diabetes, heart disease, and high blood pressure
- Obese (Class I): BMI 30.0–34.9 — significantly increased health risks
- Obese (Class II): BMI 35.0–39.9 — high health risks
- Severely obese (Class III): BMI 40.0 and above — very high risk of serious health complications
For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, the healthy BMI range is lower — 18.5 to 22.9 — because these populations face higher disease risk at lower BMI levels. Your GP can advise if adjusted thresholds apply to you.
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How It Works
Three simple steps to understand your weight and take action.
Enter your height and weight in our free calculator. Get your BMI, NHS category, healthy weight range, and ethnicity-adjusted thresholds instantly.
If your BMI suggests you're overweight or obese, explore our GLP-1 calculators to project potential weight loss on Mounjaro or Wegovy.
Use our progress tracker to log your weight weekly, visualise your journey with charts, and stay motivated — all stored privately in your browser.
Free Weight Loss Tools & Guides
Everything you need to understand your weight, explore medication options, and track your progress — completely free.
BMI Limitations and What Your Score Really Means
While a BMI score table is useful as a first screening step, BMI has important limitations. It does not distinguish between muscle and fat — athletes may have a high BMI but low body fat percentage. BMI also ignores where fat is stored; excess weight around the waist carries greater health risk than weight around the hips. Age, ethnicity, and bone density also affect what a healthy BMI means for you individually.
Your GP can assess your complete health picture, including waist circumference, blood pressure, and family history. Try our free weight converter to check your weight across different units, and remember that even small improvements in fitness and nutrition can benefit your health regardless of BMI.
- Dual GIP/GLP-1 receptor agonist
- Up to 22.5% body weight loss (SURMOUNT-1)
- Weekly injection, dose escalation over 20+ weeks
- Available via private prescription in the UK
- Doses: 2.5mg → 5mg → 7.5mg → 10mg → 12.5mg → 15mg
- GLP-1 receptor agonist
- Up to 15–17% body weight loss (STEP trials)
- Weekly injection, 5-step dose escalation
- NHS & private prescription available
- Doses: 0.25mg → 0.5mg → 1mg → 1.7mg → 2.4mg
Mounjaro vs Wegovy: Head-to-Head
A side-by-side comparison of the two most popular GLP-1 weight loss medications available in the UK.
| Feature | Mounjaro | Wegovy |
|---|---|---|
| Drug class | Dual GIP/GLP-1 agonist | GLP-1 agonist |
| Active ingredient | Tirzepatide | Semaglutide |
| Avg. weight loss | 15–22.5% | 12–17% |
| Key trial | SURMOUNT-1 (2022) | STEP 1 (2021) |
| Max dose | 15 mg weekly | 2.4 mg weekly |
| Escalation period | 20–32 weeks | 16–20 weeks |
| Administration | Weekly injection (pen) | Weekly injection (pen) |
| NHS availability | Private prescription only | NHS & private |
| Approx. private cost | £150–£250/month | £150–£300/month |
| Common side effects | Nausea, diarrhoea, constipation | Nausea, vomiting, diarrhoea |
Data sourced from SURMOUNT-1 and STEP 1 clinical trials. Costs are approximate and vary by provider. Always consult a prescriber.
Am I Eligible for Weight Loss Medication?
In the UK, eligibility for GLP-1 weight loss medications like Mounjaro and Wegovy is based on your BMI and overall health profile.
- BMI of 30 or above (obese)
- Age 18 or over
- No contraindicated conditions
- Committed to lifestyle changes
- BMI of 27 or above
- Plus type 2 diabetes
- Or high blood pressure
- Or obstructive sleep apnoea
Use our BMI calculator to check whether your BMI falls within the eligible range.
How We Built These Tools
Every calculator and guide on myweightcheck is built with accuracy and transparency in mind. Our BMI calculator uses the standard WHO formula with NHS-aligned category thresholds. Our GLP-1 projections are modelled on published clinical trial data from SURMOUNT and STEP studies.
All data stays on your device. We don't require sign-ups, and we don't store your health information on any server. Your progress tracker saves data locally in your browser using localStorage, so only you can see it.
We're based in the UK and our tools are designed specifically for UK users — supporting stone & lbs by default, referencing NHS guidelines, using NICE-approved medication data, and linking to GPhC-registered pharmacies.
Frequently Asked Questions
Common questions about BMI, weight loss medications, and our free UK tools.
What BMI score is considered healthy in the UK?
According to NHS guidelines, a healthy BMI in the UK is between 18.5 and 24.9 for most adults. For people of South Asian, Chinese, Black African, or Black Caribbean heritage, the healthy range is lower: 18.5 to 22.9. Your GP can advise whether you fall into an adjusted category.
How do I calculate my BMI from a score table?
Find your height in centimetres on the table's left side, then locate your weight in kilograms across the top. Where they meet shows your BMI score. Alternatively, use the BMI formula: weight (kg) ÷ height (m)². Our free BMI calculator does this instantly.
What does a BMI of 28 mean?
A BMI of 28 falls in the overweight category (25.0–29.9). This suggests an increased risk of type 2 diabetes, heart disease, and high blood pressure compared to the healthy weight range. Your GP can advise on whether weight management would benefit your health.
Why are BMI thresholds different for different ethnic groups?
Research shows that people of South Asian, Chinese, Black African, and Black Caribbean heritage develop weight-related diseases at lower BMI levels than other populations. The NHS therefore recommends lower healthy BMI thresholds (18.5–22.9) for these groups to better reflect their actual health risk.
Is BMI the only measure of healthy weight?
No. BMI is a useful screening tool but incomplete. Waist circumference, body fat percentage, fitness level, and blood pressure are equally important. Your GP can assess your complete health picture and discuss whether your weight poses health risks for you personally.
Ready to take control of your weight loss journey?
Start with a free BMI check, explore your GLP-1 options, or begin tracking your progress today. No sign-up. No cost. Just results.