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
Free Health Tools and UK Health Information
MyWeightCheck provides free, accessible health calculators and informational tools to support your understanding of weight management and health. Our free BMI calculator, weight converter, GLP-1 weight loss calculator, and progress tracker are designed specifically for UK measurements and aligned with NHS health thresholds. Whether you're exploring your healthy weight range, converting between stone and kilograms, or tracking progress, our tools offer evidence-based context without requiring registration. All information is educational and complements—not replaces—guidance from your GP.
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.
How MyWeightCheck Supports Your Health Journey
Free tools mean you can explore your health metrics privately and at your own pace. Our BMI calculator uses NHS categories, including ethnicity-adjusted thresholds for South Asian, Chinese, Black African, and Black Caribbean adults—because health risk varies by heritage. Our weight converter handles stone, pounds, and kilograms seamlessly, reflecting how UK adults naturally think about weight. The GLP-1 weight loss calculator provides context about eligibility and expected outcomes based on clinical trial data, helping you understand whether prescription weight management might be appropriate for discussion with your GP.
No hidden costs, no sales pressure, no registration required. Our tools are completely free because we believe health information should be accessible to everyone. Each calculator comes with NHS-aligned guidance so you understand not just the numbers, but what they mean for your health.
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.
Using Our Tools With NHS Health Advice
MyWeightCheck is designed to complement—not replace—professional NHS guidance. If your BMI calculator result suggests overweight or obesity, or if you're considering weight management options, your GP is your first point of contact. Many people find that understanding their baseline metrics using our free tools helps them have more focused conversations with their healthcare team. Our healthy weight UK guidance follows NICE and NHS recommendations, offering practical context for sustainable weight management without crash diets or unrealistic promises.
For weight-related health conditions like type 2 diabetes or high blood pressure, NHS health advice remains essential. Our tools help you understand the numbers; your GP helps you understand what's right for 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 → 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.
Are MyWeightCheck tools really free?
Yes, completely free. Our BMI calculator, weight converter, GLP-1 calculator, and progress tracker require no registration, no payment, and no personal data collection. We provide them because accessible health information matters.
How accurate is the BMI calculator?
Our BMI calculator uses the exact NHS formula and categories. However, BMI has limitations—it doesn't distinguish muscle from fat. For a complete health picture, your GP may also assess waist circumference and other factors.
Can I use MyWeightCheck to replace medical advice?
No. Our information is educational and UK health-aligned, but it doesn't replace your GP. If you're considering weight management or have health concerns, always consult your GP or healthcare professional.
Why do the tools use stone and pounds as well as kilograms?
Because most UK adults think about weight in stone and pounds, even though NHS clinical measurements use kilograms. Our weight converter and calculators offer both for clarity and ease of use.
Is my data safe on MyWeightCheck?
Our calculators don't require registration or collect personal data. You can use them privately. For detailed privacy information, review our privacy policy on the site.
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.