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 Does 18 Stone Mean for UK Health?
18 stone is approximately 114 kg or 252 pounds — a weight that carries significant health implications for most UK adults. According to NHS guidelines, this weight typically falls into the obese category for most heights, which is why understanding your personal BMI and health context is important. This guide explains what 18 stone means, how it relates to NHS health thresholds, and what resources are available to support your health journey. Use our free BMI calculator above to check your personal BMI at this weight, which will give you a clearer picture of your individual health status.
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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.
18 Stone and NHS Health Categories
At 18 stone (114.3 kg), your health category depends on your height — this is why BMI is more useful than weight alone. For example, a person 5ft 6in (168 cm) tall weighing 18 stone would have a BMI of approximately 37, which falls into the obese (Class II) category according to NHS guidelines. Someone 5ft 10in (178 cm) at the same weight would have a BMI of around 33, still in the obese range but Class I.
- Healthy weight range for 5ft 6in: approximately 7st 10lbs to 10st 4lbs (49–65 kg)
- Healthy weight range for 5ft 10in: approximately 8st 9lbs to 11st 7lbs (55–73 kg)
- Healthy weight range for 6ft: approximately 9st 7lbs to 12st 9lbs (60–80 kg)
Being at 18 stone may increase your risk of type 2 diabetes, cardiovascular disease, and high blood pressure — which is why many people in this weight range are eligible for NHS weight management support or prescription weight loss medication through specialist services.
Clinically BackedWeight Loss
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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.
NHS Support and Next Steps at 18 Stone
If you weigh around 18 stone and are concerned about your health, the NHS offers a clear weight management pathway. Your GP can refer you to specialist tier 3 weight management services, where you may be assessed for prescription weight loss medication like Mounjaro or Wegovy — particularly if you have weight-related health conditions such as type 2 diabetes, high blood pressure, or sleep apnoea. You can also access free support through the NHS Weight Loss Plan, which includes digital tools and behaviour change guidance.
Our GLP-1 weight loss calculator can help you explore what weight loss might look like with medical support. Even modest reductions — losing just 5–10% of your body weight — can meaningfully improve blood pressure, blood sugar control, and overall health. Start by speaking to your GP about your options.
- 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.
Is 18 stone overweight or obese according to NHS guidelines?
At 18 stone (114 kg), you are in the obese category for most heights according to NHS BMI thresholds. Your exact BMI depends on your height — use our free BMI calculator above to find your personal BMI. If your BMI is 30 or above, you fall into the obese range; if 35 or above, you may be eligible for NHS specialist weight management services.
What is 18 stone in kg and lbs?
18 stone equals approximately 114.3 kg or 252 pounds. You can use our free weight converter on this page to convert between stone, kilograms, and pounds instantly. These conversions are useful when checking NHS health guidance, which often uses kg measurements.
Can I access prescription weight loss medication at 18 stone?
Yes, you may be eligible for prescription weight loss medication through NHS specialist services if you have a BMI of 30 or above (or 27+ with weight-related health conditions). Your GP can refer you to tier 3 weight management services. Private access is also available following an online clinical assessment. Always consult your GP first.
What weight loss is typical starting from 18 stone?
With a combination of lifestyle changes and medical support, people typically lose 0.5–1 kg per week sustainably. Clinical trials show GLP-1 medications may help achieve average weight loss of 15–20% of body weight over several months — though individual results vary significantly. Our weight loss calculator can show projected outcomes.
What health risks are associated with weighing 18 stone?
Being 18 stone significantly increases your risk of type 2 diabetes, cardiovascular disease, high blood pressure, osteoarthritis, and non-alcoholic fatty liver disease. However, even modest weight loss — as little as 5–10% of body weight — can meaningfully reduce these risks and improve health markers. Your GP can assess your individual risk factors.
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.