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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What Is 8.9 Kilos In Pounds and What BMI Does It Give?
8.9 kilos is equivalent to 19.6 pounds (or 1 stone 5.6 lbs in stone and pounds). However, your BMI — the key health indicator — depends entirely on your height. The same weight of 8.9kg produces very different BMI values across different heights, each falling into different NHS health categories. Below, we show you exactly what BMI you'd have at various heights, and where that places you according to NHS guidelines.
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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.
What BMI Does 8.9kg Give at Different Heights?
8.9kg is a relatively light weight for adults. To convert kilograms to stone and pounds, 8.9kg equals 1 stone 5.6 lbs, or 19.6 pounds. However, BMI calculation requires both weight and height. Use our free BMI calculator above to find your exact BMI instantly. For reference, here are approximate BMI values at common UK heights:
- At 150cm (4ft 11in): BMI ≈ 39.6 (Obese Class II)
- At 160cm (5ft 3in): BMI ≈ 34.8 (Obese Class I)
- At 170cm (5ft 7in): BMI ≈ 30.8 (Obese Class I)
- At 180cm (5ft 11in): BMI ≈ 27.5 (Overweight)
- At 190cm (6ft 3in): BMI ≈ 24.6 (Healthy weight)
These examples show why height matters so much — the same weight produces very different health indicators. Our weight converter can help you switch between metric to imperial weight measurements instantly.
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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 BMI Categories and What Your Result Means
According to NHS guidelines, BMI categories for UK adults are: Healthy weight (18.5–24.9), Overweight (25.0–29.9), Obese Class I (30.0–34.9), Obese Class II (35.0–39.9), and Severely obese (40.0+). If you're of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends lower thresholds, with healthy weight being 18.5–22.9. BMI is a useful screening tool but has important limitations — it doesn't distinguish between muscle and fat, nor does it account for where fat is stored. Your GP can provide personalised advice about what your BMI means for your individual health.
- 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 8.9kg to pounds exactly?
8.9kg equals 19.6 pounds precisely. To convert kilos to pounds, multiply by 2.20462. In stone and pounds, 8.9kg is 1 stone 5.6 lbs. Our free weight converter can switch between kg, stone, and pounds instantly.
Is 8.9kg a healthy weight for an adult?
8.9kg alone doesn't tell you if it's healthy — BMI requires both weight and height. At 190cm, 8.9kg gives a healthy BMI; at 150cm, it gives an obese BMI. Use our BMI calculator to find your personal result and NHS category.
What does BMI 30 mean according to NHS guidelines?
A BMI of 30.0 or above is classified as Obese Class I by the NHS. This suggests increased health risks including type 2 diabetes and cardiovascular disease. Your GP can advise on next steps and support options.
Are BMI limitations I should know about?
Yes. BMI doesn't account for muscle mass (athletes may have high BMI but low body fat), age, or fat distribution. Waist circumference is also important. Your GP can assess your overall health beyond just BMI.
Can I use your weight loss calculator with an 8.9kg weight?
Our GLP-1 weight loss calculator is designed for adults considering prescription weight loss medication. If you're interested in weight management support, your GP can discuss options tailored 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.