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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13 Stone 8 in Kg — Quick Conversion & Health Context
13 stone 8 pounds (13st 8lbs) converts to approximately 86.18 kg. This conversion is useful whether you're checking your weight against NHS health guidance, tracking your health metrics, or simply understanding your weight in metric units. Our UK health guide explains how this weight relates to healthy weight ranges and BMI categories, helping you understand where your weight sits on the health spectrum.
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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.
How to Convert 13 Stone 8 to Kilograms
The conversion from stone and pounds to kilograms uses a straightforward formula. 13 stone 8 pounds = 86.18 kg (rounded to two decimal places). To convert any weight in stone and pounds to kg, multiply the number of stone by 6.35029 and add the pounds multiplied by 0.453592. For 13 stone 8: (13 × 6.35029) + (8 × 0.453592) = 82.554 + 3.629 = 86.18 kg.
Use our free weight converter on this page to instantly switch between stone, pounds, and kilograms — no a UK pharmacy calculation needed. This is especially helpful when comparing your weight against NHS health thresholds or checking your BMI, both of which typically use metric units (kg and metres).
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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.
What Does 86.18 kg Mean for Your Health?
At 86.18 kg, your health context depends on your height. For an adult of average UK height (around 1.70m), this weight would fall into the overweight category according to NHS guidelines, with a BMI of approximately 29.8. However, BMI varies significantly by height — a person who is 1.80m tall at 86.18 kg would have a BMI of around 26.6 (healthy weight), while someone 1.60m tall would have a BMI of about 33.6 (obese Class I).
Calculate your personal BMI using our free BMI calculator above to see exactly where your weight sits in NHS health categories. This gives you accurate health context rather than relying on weight alone.
- 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 13 stone 8 a healthy weight?
This depends entirely on your height. 13st 8 (86.18 kg) falls into different NHS categories at different heights. Use our BMI calculator to check your specific BMI — a BMI between 18.5 and 24.9 is considered healthy weight by the NHS. For South Asian, Chinese, or Black African backgrounds, the healthy range is 18.5 to 22.9.
How many kg is 13 stone 8 exactly?
13 stone 8 pounds = 86.18 kg exactly. To convert manually: multiply 13 by 6.35029 (kg per stone) and add 8 multiplied by 0.453592 (kg per pound). Our weight converter does this instantly if you prefer not to calculate by hand.
What is the healthy weight range for my height at 86.18 kg?
Your healthy weight range depends on your height. The NHS healthy BMI range is 18.5 to 24.9. To find your healthy weight range, use our free BMI calculator above, which shows your personal healthy weight band based on your exact height. This is more accurate than looking at weight alone.
Can I lose weight if I'm 13 stone 8?
Yes. Weight loss approaches include dietary changes, increased physical activity, and — for those meeting certain criteria — prescription medications. If you're interested in GLP-1 medications like Mounjaro or Wegovy, a GP or licensed prescriber can assess whether you're eligible based on your BMI and health. Try our GLP-1 weight loss calculator to see potential outcomes.
How does 13 stone 8 compare to average UK weight?
The average UK adult woman weighs around 71.6 kg (11st 3lbs), and the average UK adult man weighs around 85.7 kg (13st 7lbs). At 86.18 kg, you're very close to the average UK adult male weight. However, average weight doesn't indicate healthy weight — use NHS BMI categories instead.
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.