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
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What Is an IMT Score and How Does It Relate to UK Health?
An IMT score — often referred to as Body Mass Index (BMI) in UK health contexts — is a measurement used to assess whether an adult's weight falls within a healthy range for their height. The NHS uses BMI as a key screening tool to identify health risks linked to excess weight. Understanding your IMT score (BMI) helps you and your GP determine whether lifestyle changes, weight management support, or further health assessments are needed. This UK health guide explains how IMT scores work and what the NHS recommends.
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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.
How UK Health Services Use IMT Scores
The NHS and UK health professionals primarily use the term "BMI" rather than "IMT score", though the two terms refer to the same measurement. BMI is calculated by dividing your weight in kilograms by your height in metres squared (kg/m²). The standard NHS BMI categories are: underweight (below 18.5), healthy weight (18.5–24.9), overweight (25.0–29.9), obese class I (30.0–34.9), obese class II (35.0–39.9), and severely obese (40.0 and above).
However, the NHS also recognises that different ethnic groups face different health risks at the same BMI. For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, lower thresholds apply: healthy weight is 18.5–22.9 and overweight begins at 23.0. Your GP can advise whether these adjusted thresholds are relevant for you. Use our free BMI calculator above to check your personal BMI instantly and see which category you fall into.
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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.
IMT Score Limitations and What This Means for You
While BMI (or IMT score) is a useful initial screening tool, it has important limitations. BMI does not distinguish between muscle and fat — athletes may have a high BMI but low body fat. It also doesn't account for where fat is stored (waist circumference matters), age-related changes, or individual health differences. The NHS therefore recommends using BMI alongside other health measures, such as blood pressure, cholesterol levels, and waist measurement.
If you're unsure what your IMT score means for your individual health, your GP can provide personalised guidance. They can assess your complete health picture and recommend appropriate next steps, whether that's lifestyle advice, weight management support, or further investigations. Many UK adults benefit from discussing their weight health openly with their healthcare team.
- 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.
Is IMT score the same as BMI?
Yes. IMT is an alternative term for BMI (Body Mass Index), though the NHS primarily uses the term "BMI". Both refer to the same calculation: weight in kg divided by height in metres squared. The terms are used interchangeably in UK health contexts.
What is a healthy IMT score according to the NHS?
A healthy BMI/IMT score is between 18.5 and 24.9 for most UK adults. However, if you're of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends a healthy range of 18.5 to 22.9, as these groups face higher health risks at higher BMI levels.
How do I calculate my IMT score?
Divide your weight in kilograms by your height in metres squared. For example, if you weigh 70kg and are 1.75m tall: 70 ÷ (1.75 × 1.75) = 22.9 BMI. Our free BMI calculator on this page does this instantly for you in both metric and imperial measurements.
Does a high IMT score mean I'm unhealthy?
A high IMT score indicates increased health risk, but it's not a complete picture of your health. BMI doesn't account for muscle mass, fitness level, or where fat is stored. Your GP can assess your overall health and advise whether weight management would benefit you personally.
Can I convert my weight to check my IMT score more easily?
Yes. Our free weight converter on this page lets you switch between kilograms, stone, and pounds instantly. Once you know your weight in kilograms and your height in metres, use our BMI calculator to find your IMT score (BMI) and see which NHS category you fall into.
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.