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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8.7 Kg In Pounds — Is This A Healthy Weight?
8.7 kilograms equals 19.2 pounds in weight. However, whether this is a healthy weight for you depends entirely on your height. A weight of 8.7 kg would only be appropriate for a young child, not an adult. This guide explains healthy weight ranges using NHS guidelines and shows how to check if your weight is in the healthy zone for your individual height. Use our free BMI calculator above to find your personal healthy weight range instantly.
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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
At 8.7 kg, this weight is far below the healthy range for any adult. To help you understand healthy weights, here are three examples showing how the same weight means different things at different heights:
- At 5ft 6in (168cm): A healthy weight range is 52–70 kg (8st 2lbs – 11st 0lbs). At 8.7 kg, this would be severely underweight.
- At 5ft 10in (178cm): A healthy weight range is 57–77 kg (9st 0lbs – 12st 1lbs). Again, 8.7 kg would be dangerously low.
- At 6ft 0in (183cm): A healthy weight range is 61–82 kg (9st 8lbs – 12st 12lbs). This weight remains far below healthy levels.
These ranges follow NHS guidelines using a BMI of 18.5–24.9. The key point: your healthy weight depends on your height. Use the weight converter above to convert between kilos, stone, and pounds for context.
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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.
NHS Guidance On Healthy Weight
For adults: The NHS recommends a BMI between 18.5 and 24.9 as healthy. A weight of 8.7 kg produces a BMI far below 18.5, indicating severe underweight status. If you are concerned about being significantly underweight, speak to your GP. They can assess whether underlying health issues are involved.
Waist measurement also matters: Even at a healthy overall weight, where fat is stored affects health. Men should aim for under 94cm; women under 80cm. For South Asian, Chinese, Black African, or Black Caribbean adults, the NHS recommends lower BMI thresholds due to higher health risks at lower weights.
- 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 kg convert to in pounds?
8.7 kilograms equals exactly 19.2 pounds (lbs). To convert kilograms to pounds, multiply by 2.20462. This metric to imperial weight conversion is useful when comparing UK weights across different measurement systems.
Is 8.7 kg a healthy weight for an adult?
No. 8.7 kg is far below the healthy weight range for any adult of any height. A healthy adult weight typically ranges from 50–100+ kg depending on height. At 8.7 kg, someone would be severely underweight and should seek GP advice immediately.
How do I know if my weight is healthy?
Use our free BMI calculator on this page to check your personal BMI against NHS guidelines. Alternatively, ask your GP to assess your healthy weight range based on your height, age, and health status. BMI of 18.5–24.9 is the NHS healthy range for most adults.
What if I'm significantly underweight?
If you are underweight (BMI below 18.5) or concerned about your weight, contact your GP. Underweight status can indicate malnutrition, eating disorders, or underlying health conditions. Your GP can refer you to specialist support if needed.
How do I convert kg to stone and pounds easily?
Use our weight converter tool above to instantly convert between kilograms, stone, and pounds. Alternatively: divide kg by 6.35 for stone, or multiply kg by 2.20462 for pounds. Stone and pounds are the traditional UK measurements, while kg is metric.
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.