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
Body Weights — UK Health Guidance
Body weight is a key health indicator, but what constitutes a healthy weight varies from person to person depending on height, age, and individual factors. In the UK, the NHS uses BMI (body mass index) as the primary screening tool to assess whether a weight falls within a healthy range. However, weight alone doesn't tell the full story — your overall health depends on fitness, diet, lifestyle, and family history. Understanding your body weight in the context of NHS guidance helps you make informed decisions about your health. Our free BMI calculator and weight converter can help you assess your personal weight status instantly.
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 Guidance on Healthy Body Weights
The NHS defines healthy weight ranges using BMI categories, which apply to adults aged 18 and over. A healthy BMI falls between 18.5 and 24.9 kg/m². For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends lower thresholds — a healthy BMI is 18.5 to 22.9 — because these groups face higher health risks at lower BMI levels.
However, BMI has important limitations. It doesn't distinguish between muscle and fat, so athletes or very muscular individuals may have a high BMI but low body fat. BMI also doesn't account for where fat is stored — waist circumference matters too. The NHS recommends that men keep their waist below 94cm (37 inches) and women below 80cm (31.5 inches) to reduce health risks.
Weight management across the UK varies by region. NHS tier 3 and tier 4 weight management services offer support for those with obesity and weight-related health conditions. Many areas also offer community programmes and digital tools to help with healthy weight maintenance.
Clinically BackedWeight Loss
No appointments. No waiting rooms. Just care — from a UK-regulated online pharmacy.
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.
Tools and Resources for Understanding Your Weight
The best way to understand whether your body weight is healthy for your height is to use our free BMI calculator — simply enter your weight and height, and it instantly shows your BMI category and healthy weight range. For those tracking progress over time, our free progress tracker lets you log weight changes and see trends week by week.
If you need to convert between UK measurements, our weight converter quickly translates between kilograms, stone, and pounds — all the units you'll encounter in NHS guidance and UK health resources. Your GP can also provide personalised advice about what your weight means for your individual health, especially if you have weight-related health conditions or are considering weight management support.
- 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 is the healthy weight range for my height in the UK?
The NHS defines healthy weight using BMI. Calculate your BMI using our free BMI calculator above — enter your height and weight, and it will show your healthy weight range. For most adults, a BMI between 18.5 and 24.9 is considered healthy. However, if you're of South Asian, Chinese, Black African, or Black Caribbean heritage, a BMI between 18.5 and 22.9 is recommended by the NHS.
Does a higher body weight always mean poor health?
Not necessarily. BMI doesn't account for muscle mass, bone density, or overall fitness. A muscular athlete might have a high BMI but excellent health markers. However, excess body fat — especially around the stomach — does increase risk of type 2 diabetes, heart disease, and joint problems. Your GP can assess your individual health beyond just weight.
How much weight should I aim to lose per week?
The NHS recommends losing weight at a safe rate of 0.5 to 1 kg (1 to 2 pounds) per week. This requires a calorie deficit of around 500 kcal per day and is achieved through a combination of dietary changes and increased physical activity. Faster weight loss can lead to muscle loss and is not sustainable long-term.
What is considered overweight in the UK according to the NHS?
According to NHS guidelines, a BMI between 25.0 and 29.9 is classified as overweight. At this stage, weight-related health risks begin to increase, particularly if you have other risk factors like high blood pressure or family history of diabetes. Your GP can advise on whether weight management support would benefit your health.
Can I access weight management support through the NHS?
Yes. The NHS offers weight management services through tier 3 and tier 4 specialist services, usually accessed via referral from your GP. Access and waiting times vary significantly by region. You can also explore tier 1 and tier 2 options — community weight management programmes and digital tools — which are often available locally without a referral. ```
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.