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 kg in Stone?
8.5 kilograms is equal to 1 stone and 5.4 pounds (or 1st 5.4lbs). To convert kilograms to stone, divide the kilogram value by 6.35029. This quick conversion uses the standard kg to stone formula used across the UK. Use our free weight converter above to instantly switch between metric and imperial measurements, or check your BMI at this weight using our free BMI calculator.
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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.
8.5 Kg to Stone Conversion Table & Formula
The exact kg to stone conversion formula is: kilograms ÷ 6.35029 = stone. For 8.5 kg: 8.5 ÷ 6.35029 = 1.34 stone (1 stone 5.4 pounds). The table below shows nearby values to help you see the kilogram to stone conversion at a glance:
| Kilograms | Stone & Pounds | Pounds |
|---|---|---|
| 6 kg | 0st 13.2lbs | 13.2 lbs |
| 7 kg | 1st 1.5lbs | 15.4 lbs |
| 8 kg | 1st 4.6lbs | 17.6 lbs |
| 8.5 kg | 1st 5.4lbs | 18.7 lbs |
| 9 kg | 1st 6.6lbs | 19.8 lbs |
| 10 kg | 1st 8.8lbs | 22.0 lbs |
| 11 kg | 1st 12.1lbs | 24.3 lbs |
Stone and pounds are traditional UK weight measurements. One stone equals exactly 14 pounds, so 1st 5.4lbs means 1 stone plus 5.4 pounds.
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 Context & Healthy Weight at 8.5 kg
At 8.5 kg, your BMI depends entirely on your height. For reference, at an average UK height of 1.73m (5ft 8in), a weight of 8.5 kg would result in a BMI of 2.8 — well below the healthy range. This weight is only typical for infants and very young children. For children, BMI is calculated differently using age and sex-specific centile charts — never adult BMI categories. If you're looking for your personal healthy weight range, use our free BMI calculator above to enter your exact height and current weight for accurate context and NHS-aligned guidance.
- 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 8.5 kg to stone manually?
Divide 8.5 by 6.35029 to get stone. 8.5 ÷ 6.35029 = 1.34 stone. To express this as stone and pounds, multiply the decimal (0.34) by 14: 0.34 × 14 = 4.76 pounds, giving 1 stone 5.4 pounds total.
What is 8.5 kg in pounds?
8.5 kg equals 18.7 pounds. Use the formula: kilograms × 2.20462 = pounds. So 8.5 × 2.20462 = 18.7 lbs. The weight converter tool on this page can convert instantly between all units.
Is 8.5 kg a healthy weight for an adult?
No. 8.5 kg is far below a healthy adult weight — it is typical only for infants. Healthy adult weight ranges from approximately 50–100 kg depending on height. Use our free BMI calculator to find your personal healthy weight range based on your actual height.
How does 8.5 kg compare to average UK adult weight?
The average UK adult weighs around 80–85 kg, so 8.5 kg is roughly one-tenth of typical adult body weight. This weight would only be healthy for a newborn or very young infant. For adult weight context, see the BMI calculator above.
Can I use this conversion for medication dosing?
No. Never use general weight converters for medication dosing. Always consult your GP or pharmacist for medication calculations. They will use precise weight measurements and clinical guidelines specific to your health needs.
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.