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
How Much Weight Should You Lose On Mounjaro?
Your target weight should be based on your height and overall health, not just a number on the scales. The NHS defines a healthy weight range using BMI (body mass index) of 18.5 to 24.9 for most adults. If you're considering Mounjaro, the goal isn't a specific weight loss amount — it's reaching a healthier weight range for your individual circumstances. Clinical trials showed Mounjaro helped participants lose an average of 15–21% of their body weight, but individual results vary significantly. Your GP can help you set realistic, personalised targets based on your health profile and starting point.
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.
Healthy Weight Range By Height
Your ideal weight depends primarily on your height. Use our free BMI calculator above to check what weight range is healthy for you. Here are healthy weight ranges (BMI 18.5–24.9) for common UK heights:
- 5ft 2in (157cm): 46–59 kg (7st 3lbs – 9st 4lbs)
- 5ft 4in (163cm): 49–64 kg (7st 10lbs – 10st 1lbs)
- 5ft 6in (168cm): 52–68 kg (8st 2lbs – 10st 10lbs)
- 5ft 8in (173cm): 55–74 kg (8st 10lbs – 11st 9lbs)
- 5ft 10in (178cm): 59–78 kg (9st 4lbs – 12st 4lbs)
- 6ft (183cm): 62–83 kg (9st 11lbs – 13st 1lb)
These ranges are based on NHS healthy weight guidelines. The weight for height that's right for you depends on your individual health, muscle mass, and frame size. Try our free weight converter above to switch between kg, stone, and lbs instantly.
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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.
Individual Factors That Affect Your Target Weight
Your ideal weight isn't just about height — several factors matter. Muscle mass is heavier than fat, so athletes or very active people may have a higher healthy weight. Frame size also varies: some people naturally carry more weight at the same height. Age affects metabolism; older adults may need different targets. Ethnicity matters too — the NHS recommends lower BMI thresholds (18.5–22.9) for South Asian, Chinese, Black African, and Black Caribbean adults due to higher health risks at the same weight.
Rather than chasing a specific number, focus on what matters: improved energy, better blood pressure, improved mobility, and reduced disease risk. Our GLP-1 weight loss calculator can help you set realistic expectations if you're considering Mounjaro alongside lifestyle changes.
- 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's the average weight loss on Mounjaro?
Clinical trials (SURMOUNT-1) showed participants lost an average of 15–21% of their body weight over 72 weeks on Mounjaro, alongside a reduced-calorie diet and increased physical activity. Individual results vary — some people lose more, some less. Weight loss depends on your starting weight, adherence, diet, and exercise.
Should I aim for a specific weight when taking Mounjaro?
Rather than targeting a specific weight, aim for a healthy BMI range (18.5–24.9 for most adults) that's sustainable for your height and health. Your GP or prescriber can help you set realistic goals based on your starting point and health conditions. gradual weight management isn't always better — sustainable loss is healthier long-term.
How does Mounjaro help you lose weight?
Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist that may help reduce appetite, support feeling fuller after smaller meals, and slow how quickly food leaves your stomach. It's a prescription-only medicine that works best alongside a reduced-calorie diet and increased physical activity — not as a replacement for lifestyle changes.
What if I don't reach a "healthy" BMI on Mounjaro?
Even modest weight loss (5–10% of body weight) can significantly improve health outcomes: lower blood pressure, better blood sugar control, reduced joint pain, and improved energy. Reaching a specific BMI isn't the only measure of success. Your GP can discuss what realistic and healthy looks like for your individual circumstances.
How do I know what weight is right for me?
Use our free BMI calculator above to find your healthy weight range based on your height. For personalised advice, speak with your GP, who can consider your medical history, medications, age, and health conditions. They can help set targets that are both realistic and beneficial for your health.
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.