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 18.2 Stone in Kilograms?
18.2 stone is equivalent to 115.7 kilograms. This conversion uses the standard UK stone to kg formula: multiply stone by 6.35029. However, whether this weight is healthy for you depends entirely on your height. The same weight gives very different BMI results at different heights. Use our free BMI calculator above to find your personal BMI, or read on to see example BMI values at common heights for someone weighing 18.2 stone.
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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.
BMI at Different Heights for 18.2 Stone
At 18.2 stone (115.7 kg), your BMI depends on your height. Here are example BMI values at common UK heights:
- 5ft 2in (157 cm): BMI 46.9 — Severely obese (Class III)
- 5ft 5in (165 cm): BMI 42.6 — Severely obese (Class III)
- 5ft 8in (173 cm): BMI 39.2 — Obese (Class II)
- 5ft 10in (178 cm): BMI 37.1 — Obese (Class II)
- 6ft (183 cm): BMI 35.2 — Obese (Class II)
- 6ft 2in (188 cm): BMI 33.6 — Obese (Class II)
These examples show how the same weight gives different BMI categories depending on height. Use the weight converter on this page to check other weight values in kilograms or stone, and the BMI calculator to find your exact personal BMI.
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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.
Understanding NHS BMI Categories
The NHS defines BMI categories as follows: under 18.5 is underweight, 18.5–24.9 is healthy weight, 25–29.9 is overweight, 30–34.9 is obese (Class I), 35–39.9 is obese (Class II), and 40 and above is severely obese (Class III). If you are of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends lower thresholds: healthy BMI is 18.5–22.9, overweight starts at 23, and obese starts at 27.5. Remember that BMI does not account for muscle mass — athletes may have a high BMI but low body fat. If you're concerned about your weight or health, speak with your GP for personalised 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.
How do I convert 18.2 stone to kilograms exactly?
Multiply 18.2 by 6.35029. The result is 115.7 kg. This is the standard kg to stone conversion used in the UK. You can also use the weight converter on this page for instant conversions between stone, pounds, and kilograms.
Is 18.2 stone a healthy weight?
It depends on your height. At most adult heights, 18.2 stone (115.7 kg) results in a BMI in the obese range. However, BMI is a screening tool with limitations — it doesn't distinguish between muscle and fat. Your GP can assess your individual health and discuss whether weight management would benefit you.
What BMI does 18.2 stone give at 5ft 8in?
At 5ft 8in (173 cm), 18.2 stone (115.7 kg) gives a BMI of 39.2, which falls into the obese (Class II) category according to NHS guidelines. Use our free BMI calculator above to find your exact BMI if you know your height.
How much weight would I need to lose to reach a healthy BMI?
The weight needed depends on your height. For example, at 5ft 8in, a healthy BMI (18.5–24.9) corresponds to a weight range of approximately 55–74 kg (8st 9lbs to 11st 8lbs). Your GP or a healthcare professional can discuss a safe, sustainable weight loss plan tailored to your health.
Can I lose weight with prescription medication?
Yes, prescription weight loss medications are available in the UK for adults who meet eligibility criteria. These are typically prescribed through NHS specialist weight management services or by private prescribers following a clinical assessment. Medications work alongside diet and physical activity. Try our GLP-1 weight loss calculator to see projected outcomes at different treatment levels.
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.