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 BMI Does 8.9 Kg In Lbs Give You?
8.9 kilograms converts to 19.6 pounds — but your BMI depends entirely on your height. A weight of 8.9 kg is very light for an adult, and the BMI it produces varies significantly based on how tall you are. Below we show what BMI this weight gives at different heights, and which NHS category each falls into. Use our free BMI calculator above to check your exact BMI instantly by entering your height and weight.
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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.
BMI At 8.9 Kg For Different Heights
At 8.9 kg (19.6 lbs), your BMI depends on your height. Here are example BMI values at common adult heights:
- 160 cm (5ft 3in): BMI 34.8 — Obese (Class I)
- 165 cm (5ft 5in): BMI 32.7 — Obese (Class I)
- 170 cm (5ft 7in): BMI 30.8 — Obese (Class I)
- 175 cm (5ft 9in): BMI 29.1 — Overweight
- 180 cm (5ft 11in): BMI 27.4 — Overweight
- 185 cm (6ft 1in): BMI 26.0 — Overweight
At 8.9 kg, the NHS healthy weight range for any adult is significantly higher. Convert kilograms to stone to see your weight in imperial units more clearly.
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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.
Understanding NHS BMI Categories
According to NHS guidelines, a healthy BMI sits between 18.5 and 24.9 for most adults. At 8.9 kg, you would fall into the overweight or obese category depending on height. For South Asian, Chinese, Black African, or Black Caribbean adults, the NHS recommends lower thresholds — healthy BMI starts at 18.5 and overweight begins at 23.0. Remember that BMI has limitations: it doesn't distinguish muscle from fat, and doesn't account for where weight is stored. Use the weight converter on this page to check your weight in stone and pounds alongside your BMI assessment.
- 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 8.9 kg convert to in pounds?
8.9 kg equals 19.6 pounds (lbs). To convert kilograms to pounds, multiply by 2.20462. So 8.9 × 2.20462 = 19.6 lbs. You can also convert between metric to imperial weight using our free weight converter above for gradual improvement.
Is 8.9 kg a healthy weight for an adult?
At 8.9 kg, this weight is significantly below the healthy range for any adult regardless of height. A healthy weight for adults typically ranges from around 50 kg to 90+ kg depending on height. If you're concerned about being underweight, speak to your GP who can assess your individual health needs.
What is the BMI at 8.9 kg and 170 cm?
At 8.9 kg and 170 cm (5ft 7in), your BMI would be approximately 30.8, which falls into the Obese (Class I) category according to NHS guidelines. However, note that BMI doesn't account for muscle mass or fat distribution — your GP can give you personalised health advice.
How do I calculate my BMI with this weight?
BMI = weight (kg) ÷ height (m)². For 8.9 kg, divide by your height in metres squared. Use our free BMI calculator above to enter your exact height and weight for an instant, accurate result with NHS category classification.
Are there different BMI categories for different ethnic groups?
Yes. The NHS recommends lower BMI thresholds for adults of South Asian, Chinese, Black African, and Black Caribbean heritage because these groups face higher health risks at lower BMI levels. Healthy weight for these groups starts at 18.5 and overweight begins at 23.0, compared to 25.0 for other populations.
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.