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
Understanding Your Weight and Healthy Weight Management
Weight is a key health indicator, but it's just one part of your overall fitness picture. Your weight affects your risk of type 2 diabetes, heart disease, joint problems, and other health conditions — which is why understanding your healthy weight range matters. In the UK, we use stone and pounds alongside kilograms, and the NHS provides clear guidance on what constitutes a healthy weight for different heights. Use our free BMI calculator above to check where you currently stand, and explore what a healthy weight range means for you personally.
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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.
What Makes a Healthy Weight in the UK?
According to NHS guidance, a healthy weight isn't a single number — it's a range based on your height. The NHS uses BMI (body mass index) as the primary screening tool, with a healthy BMI range of 18.5 to 24.9 for most UK adults. However, for people of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends lower thresholds (18.5 to 22.9) because these groups face higher cardiovascular and diabetes risks at the same BMI.
To find your personal healthy weight range, use the weight converter on this page to switch between metric and imperial measurements, then apply your height. For example, at 5ft 8in (173cm), a healthy weight range is approximately 55–74 kg (8st 8lbs to 11st 8lbs). Weight management involves three key factors: diet, physical activity, and sustained behaviour change. The NHS recommends losing weight gradually — no more than 0.5–1 kg per week — for sustainable results. Even a 5–10% reduction in body weight can improve blood pressure, blood sugar control, and reduce joint strain.
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.
Weight Management Options Available in the UK
If you're overweight and struggling to lose weight through diet and exercise alone, the NHS offers a structured pathway through specialist weight management services. For adults with a BMI of 30 or above (or 27 with weight-related health conditions like type 2 diabetes or high blood pressure), prescription weight loss medications may be available. Wegovy (semaglutide) and Mounjaro (tirzepatide) are GLP-1 receptor agonist injections licensed for weight management in the UK — both require a prescription and clinical assessment. These medications may help reduce appetite and support weight loss when combined with lifestyle changes. Try our GLP-1 weight loss calculator to explore potential results at different doses, and discuss with your GP whether specialist weight management services are right for you.
- 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 considered a healthy weight in the UK?
The NHS defines healthy weight using BMI 18.5–24.9 for most adults, or 18.5–22.9 for South Asian, Chinese, Black African, or Black Caribbean adults. A healthy weight range depends on your height. Use our free BMI calculator to find your personal range. Even small weight reductions of 5–10% offer measurable health benefits.
How much weight should I aim to lose per week?
The NHS recommends losing 0.5–1 kg (1–2 lbs) per week for sustainable, safe weight loss. This typically requires a calorie deficit of around 500 kcal per day. Faster weight loss can lead to muscle loss and is not recommended without medical supervision.
When should I consider weight loss medication or specialist help?
Speak to your GP if you have a BMI of 30 or above, or 27 or above with weight-related health conditions (diabetes, high blood pressure, high cholesterol). Your GP can refer you to NHS specialist weight management services, where prescription medications like Wegovy or Mounjaro may be discussed.
Are prescription weight loss injections available on the NHS?
Yes, but access is through specialist tier 3/4 weight management services, not standard GP prescription. NICE has approved tirzepatide (Mounjaro) and semaglutide (Wegovy) for NHS use. Availability and waiting times vary significantly by region. Private access is also available through online prescribers.
What tools can help me track my weight management progress?
MyWeightCheck offers several free tools: our BMI calculator to monitor your BMI, the weight converter to track weight in different units, and a progress tracker to log your weight loss journey over time. These help visualise your progress towards your healthy weight range.
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.