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 8.5 Stone in Kilograms?
8.5 stone is equivalent to approximately 54 kilograms (53.98 kg to be precise). In UK health guidance, understanding your weight in both stone and kilograms is important because NHS health professionals use metric measurements for clinical assessments, while many UK adults still think in terms of stone. Whether you're tracking your health, preparing for a GP appointment, or comparing your weight to NHS guidance, knowing this conversion helps you understand where you sit on healthy weight charts and what this means for your overall wellbeing.
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 Does 8.5 Stone Compare to Healthy Weight in the UK?
To assess whether 8.5 stone (54 kg) is a healthy weight for you, your height matters significantly. A healthy weight range depends on how tall you are — the NHS uses Body Mass Index (BMI) to determine this. For example, if you're 5ft 4in (163cm) tall, 8.5 stone gives a BMI of around 23, which falls within the healthy weight range of 18.5–24.9. If you're taller, say 5ft 10in (178cm), the same weight would give a BMI of approximately 20, also healthy. However, if you're significantly shorter, your BMI could be higher. Use our free BMI calculator above to check your personal BMI instantly — it takes just seconds and gives you a clear picture of where you sit according to NHS guidance. For those of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends slightly lower thresholds, with a healthy range starting at 18.5 and ending at 22.9 rather than 24.9.
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.
UK Health Tools and Next Steps
Understanding your weight is just one part of managing your health in the UK. The NHS recommends discussing any concerns about your weight with your GP, who can give personalised advice based on your age, medical history, and individual circumstances. If you want to track changes over time, our free progress tracker helps you log your weight journey. You can also use our weight converter tool to switch between stone, pounds, and kilograms whenever needed. Remember that weight is influenced by many factors including genetics, metabolism, medications, and lifestyle — it's never just about the number on the scales.
- 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 8.5 stone a healthy weight?
It depends on your height. At 5ft 4in, 8.5 stone gives a BMI of about 23 (healthy). At 5ft 8in, it's roughly 21 (healthy). At 5ft 2in, it could be around 25 (overweight). Use the BMI calculator on this page to find your personal BMI based on your height.
What does 8.5 stone equal in kilograms?
8.5 stone equals approximately 54 kg. To convert: multiply stone by 6.35. So 8.5 × 6.35 = 53.98 kg. Our weight converter above lets you switch between all UK measurements instantly.
How does NHS guidance define healthy weight?
The NHS says a healthy BMI is 18.5–24.9 for most adults. For South Asian, Chinese, Black African, and Black Caribbean adults, it's 18.5–22.9. Your healthy weight range depends on your height. Your GP can give personalised guidance.
Should I be concerned if I weigh 8.5 stone?
Weight alone isn't a complete picture of health. What matters is whether it's healthy for your height, age, and medical history. Talk to your GP if you have concerns. They can assess your individual health and advise if any changes would benefit you.
How can I track my weight over time?
Our free progress tracker on this page lets you log your weight regularly and see trends. Regular tracking helps you stay motivated and shows whether lifestyle changes are working. You can also use our weight converter to switch between stone and kg whenever needed.
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.