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
Is 8.7 Pounds a Healthy Weight?
8.7 pounds equals approximately 3.95 kilograms using the standard metric conversion. Whether this weight is healthy depends entirely on your height — there's no single "healthy weight" that applies to everyone. Using NHS guidelines and the BMI formula, a weight of 3.95kg would only be healthy for a very young child, not an adult. If you're converting your own weight, use our free weight converter to switch between kilograms and stone, then check your BMI against NHS healthy weight ranges for adults.
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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.
Healthy Weight Ranges by Height
For adults, a healthy weight falls within a specific range that depends on your height. The NHS uses BMI (body mass index) to define healthy weight ranges. A healthy BMI is between 18.5 and 24.9 for most UK adults. Below are approximate healthy weight ranges for common UK heights — to convert kilograms to stone, divide by 6.35.
- 5ft 4in (163cm): Healthy range is 48–63kg (7st 6lbs–9st 13lbs)
- 5ft 7in (170cm): Healthy range is 53–70kg (8st 4lbs–11st 0lbs)
- 5ft 10in (178cm): Healthy range is 59–77kg (9st 4lbs–12st 2lbs)
For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends lower thresholds — healthy weight range is slightly narrower. Calculate your personal BMI instantly using our free BMI calculator on this page to see exactly where you fall.
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.
NHS Guidance and Next Steps
If your weight falls outside the healthy range for your height, the NHS recommends speaking to your GP, who can offer personalised advice and support. Weight is influenced by many factors including genetics, medical conditions, medications, and lifestyle. A waist measurement is also important — for men, over 94cm (37 inches) indicates increased health risk; for women, over 80cm (31.5 inches) does the same. Even losing 5–10% of your body weight can bring meaningful health benefits. Track your progress using our free progress tracker, and remember that sustainable weight change takes time and support.
- 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.
What does 8.7 pounds equal in kilograms?
8.7 pounds equals approximately 3.95 kilograms. To convert pounds to kg, divide the pound value by 2.20462. You can use our free weight converter above to instantly convert between pounds, kilograms, and stone.
Is 8.7 pounds a healthy adult weight?
8.7 pounds (3.95kg) is not a realistic adult body weight — it's far below any healthy range. If you meant a different weight value, use our BMI calculator to check whether your actual weight is healthy based on your height using NHS guidelines.
How do I know if my weight is healthy?
Your healthy weight depends on your height and is measured using BMI. Use our free BMI calculator on this page, or check the NHS healthy weight ranges table above for your approximate height. Speak to your GP if you're unsure or have health concerns.
What's the difference between stone and kilograms?
Stone and kilograms are both weight units used in the UK. 1 stone equals 6.35kg exactly. To convert kilograms to stone, divide by 6.35; to convert stone to kg, multiply by 6.35. Our weight converter makes this instant.
What should I do if I'm outside the healthy weight range?
Speak to your GP, who can offer personalised advice based on your health. The NHS recommends sustainable weight loss of 0.5–1kg per week. Small changes to diet and physical activity can help, and your GP may discuss additional support or treatment options available to you.
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.