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
What Is Overweight โ A UK Health Guide
Being overweight means your weight falls within a specific range according to health guidelines. In the UK, the NHS defines overweight as having a BMI (body mass index) between 25.0 and 29.9. This is different from obesity, which starts at a BMI of 30 or above. Understanding whether you're overweight is important because it helps you assess your health risk. Check your personal BMI using our free BMI calculator above to see where you fall on the health spectrum.
10,000+ calculations today ยท NHS-aligned thresholds ยท 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/mยฒ).
While BMI isn't a perfect measure โ it doesn't account for muscle mass, bone density, or fat distribution โ 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 โ 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.
Health Conditions Linked to Excess Weight
Carrying excess weight increases your risk of developing several serious health conditions. Type 2 diabetes is significantly more common in people who are overweight or obese โ in fact, around 90% of type 2 diabetes cases are associated with excess weight. High blood pressure (hypertension) is also strongly linked to being overweight, which puts extra strain on your heart and blood vessels. Cardiovascular disease, including heart attacks and strokes, is more likely with higher BMI levels.
Other conditions associated with excess weight include high cholesterol, which narrows arteries and increases heart disease risk, obstructive sleep apnoea (disrupted breathing during sleep), osteoarthritis (joint damage), and fatty liver disease. Research also suggests that being overweight increases the risk of certain cancers, including breast, bowel, and endometrial cancer. The good news is that losing even just 5โ10% of your current body weight can significantly reduce these risks and improve your health markers.
Clinically BackedWeight Loss
No appointments. No waiting rooms. Just care โ 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 โ 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 โ completely free.
Support Available โ NHS and Beyond
If you're overweight and concerned about your health, the NHS offers support through its weight management pathway. Your first step is to speak with your GP, who can discuss your health history, assess your personal risk, and suggest appropriate support. This may include free lifestyle programmes, such as the NHS Weight Loss Plan, which offers digital guidance on diet and activity.
For eligible adults, prescription weight loss medications may be considered by specialist services. These work alongside lifestyle changes rather than replacing them. You can also use our free weight loss calculator to explore potential outcomes. Visit your GP for a personal assessment โ they'll help you decide what's right for you based on your individual circumstances.
- 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 โ 5mg โ 7.5mg โ 10mg โ 12.5mg โ 15mg
- GLP-1 receptor agonist
- Up to 15โ17% body weight loss (STEP trials)
- Weekly injection, 5-step dose escalation
- NHS & private prescription available
- Doses: 0.25mg โ 0.5mg โ 1mg โ 1.7mg โ 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 | 15โ22.5% | 12โ17% |
| Key trial | SURMOUNT-1 (2022) | STEP 1 (2021) |
| Max dose | 15 mg weekly | 2.4 mg weekly |
| Escalation period | 20โ32 weeks | 16โ20 weeks |
| Administration | Weekly injection (pen) | Weekly injection (pen) |
| NHS availability | Private prescription only | NHS & private |
| Approx. private cost | ยฃ150โยฃ250/month | ยฃ150โยฃ300/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 โ 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 exact BMI range for overweight according to the NHS?
The NHS defines overweight as a BMI between 25.0 and 29.9. You can calculate your personal BMI using our free BMI calculator above by entering your height and weight. Your GP can also help you understand what your BMI means for your health.
Is being overweight the same as being obese?
No. Overweight and obesity are different categories. Overweight is a BMI of 25.0โ29.9, while obesity begins at a BMI of 30.0 and above. Obesity carries higher health risks than being overweight, though both can benefit from lifestyle support and, where appropriate, medical intervention.
How much weight do I need to lose to improve my health?
Evidence suggests that losing just 5โ10% of your body weight can meaningfully improve your health โ lower blood pressure, better blood sugar control, reduced joint pain, and improved cholesterol levels. This is often more achievable than aiming for a "goal weight" and can provide real health benefits.
What is the healthy weight range for my height?
The healthy weight range (BMI 18.5โ24.9) varies by height. For example, a person who is 1.73m (5ft 8in) has a healthy range of approximately 55โ74kg (8st 10lbsโ11st 10lbs). Use our free BMI calculator and weight converter above to find your personal healthy weight range instantly.
Should I see my GP about being overweight?
Yes, it's worth discussing with your GP, especially if you have health concerns or a family history of obesity-related conditions like type 2 diabetes. Your GP can assess your personal risk, discuss lifestyle changes, and โ if eligible โ refer you to specialist support or weight management services on the NHS.
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.