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
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Understanding BMI When You Weigh in Stone
If you weigh yourself in stone and pounds, calculating your BMI is straightforward once you convert your weight to kilograms. Your BMI (body mass index) is a health screening tool that compares your weight to your height to indicate whether you're in a healthy weight range according to NHS guidelines. Understanding your BMI helps you identify whether your current weight poses any health risks and is a useful starting point for discussing health with your GP.
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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 to Calculate BMI from Stone
To calculate your BMI formula from stone, first convert your weight to kilograms: multiply your stone by 6.35, then add any additional pounds multiplied by 0.454. Then use the standard formula: BMI = weight (kg) ÷ height (m)². For example, if you weigh 11 stone (70 kg) and are 1.75m tall, your BMI would be approximately 22.9, which falls in the healthy BMI range.
The healthy bmi range according to NHS guidelines is 18.5 to 24.9. Use our free BMI calculator above to enter your weight in stone and height instantly—it will calculate your exact BMI and tell you which bmi categories uk you fall into. For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, the nhs bmi thresholds are lower, starting at 18.5 to 22.9 for healthy weight.
- Underweight: below 18.5
- Healthy weight: 18.5–24.9
- Overweight: 25.0–29.9
- Overweight bmi threshold (obesity): 30.0 and above
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.
BMI Limitations and What Else Matters
While BMI is a useful screening tool, bmi limitations are important to understand. BMI does not distinguish between muscle and fat—athletes may have a high BMI but low body fat percentage. It also does not account for where fat is stored; waist circumference is equally important. Men with a waist over 94cm (37 inches) and women over 80cm (31.5 inches) have increased health risk, regardless of BMI.
For a complete picture of your health, your GP may also consider your waist-to-height ratio, blood pressure, cholesterol, and family history. Use our free weight converter to check your weight in different units, and discuss your personal health goals with your GP. Bmi calculator tools like those on MyWeightCheck provide instant insight, but they should complement, not replace, professional health advice.
- 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 a good BMI in stone and pounds?
A healthy BMI is 18.5–24.9 according to NHS guidelines. If you weigh 10 stone (63.5kg) and are 1.70m tall, your BMI is approximately 22, which is healthy. Use our BMI calculator to instantly see where your stone and pounds measurement falls.
How do I convert stone to BMI?
Convert stone to kilograms (stone × 6.35), then divide by your height in metres squared. For example, 12 stone (76kg) at 1.75m height = BMI of 24.8. Our free calculator does this instantly—just enter your stone weight and height above.
What BMI range is overweight in UK terms?
According to NHS guidelines, a BMI of 25.0–29.9 is classified as overweight. This means health risks begin to increase. Your GP can advise whether lifestyle changes or further assessment is needed based on your individual health.
Is BMI different for people who measure in stone?
No, BMI calculation is the same regardless of units used. However, UK adults traditionally use stone and pounds, so understanding how to interpret your stone weight within BMI ranges helps make the health screening more meaningful and actionable.
What should I do if my BMI in stone puts me in the overweight category?
Talk to your GP about your results. Even a 5–10% weight reduction can improve health markers. Your GP may recommend dietary changes, increased activity, or referral to NHS weight management services. Tools like our weight converter and progress tracker can help you monitor changes.
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.