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
8.9 Pounds in Kg — Healthy Weight Context
8.9 pounds is equivalent to 4.04 kilograms. Whether this weight is healthy for you depends entirely on your height. A healthy weight range varies significantly between individuals — what's healthy for a 5ft 4in adult is very different from what's healthy for someone 6ft tall. This guide shows you how to find your personal healthy weight range using NHS guidelines and explains what to do if you're concerned about your weight. Use our free BMI calculator above to check your personal BMI instantly based on your weight and height.
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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 (UK)
Your healthy weight range depends on your height. Below are healthy weight ranges in kilograms for different heights according to NHS guidelines:
- 5ft 0in (152cm): 44–59 kg (6st 12lbs – 9st 3lbs)
- 5ft 4in (163cm): 50–67 kg (7st 12lbs – 10st 7lbs)
- 5ft 8in (173cm): 55–74 kg (8st 9lbs – 11st 8lbs)
- 6ft 0in (183cm): 61–82 kg (9st 8lbs – 12st 13lbs)
At 4.04 kg, this weight would be appropriate for a very young child or infant only — not a typical weight for an adult. To find your healthy range, use our weight converter to switch between kg, stone, and pounds, then cross-reference with your height above. The standard metric to imperial weight conversion shows how the same weight means very different things depending on your height and frame.
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
The NHS recommends a healthy BMI between 18.5 and 24.9 for most UK adults. If you're concerned about whether your weight is healthy for your height, your GP can provide personalised guidance. Waist measurement also matters: men should aim for under 94 cm (37 inches), women under 80 cm (31.5 inches). If you're carrying excess weight, the good news is that even a 5–10% reduction can improve your health significantly. Track your progress with our free progress tracker, and remember that sustainable weight loss of 0.5–1 kg per week is recommended. If you need support, ask your GP about NHS weight management services or tier 3 specialist support available in your area.
- 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 8.9 pounds to kilograms?
Multiply 8.9 by 0.453592. This equals 4.04 kg. You can also use our free weight converter on this page to convert between pounds, kilograms, stone, and any other unit instantly.
Is 4.04 kg a healthy weight for an adult?
No — 4.04 kg would only be appropriate for a newborn or very young infant. For adults, healthy weight depends on height. A 5ft 4in adult might be healthy at 50–67 kg, whilst a 6ft adult would be healthy at 61–82 kg. Use the BMI calculator to check your personal healthy range.
How do I know if my weight is healthy?
Calculate your BMI using your weight and height. The NHS healthy BMI range is 18.5–24.9. Lower thresholds apply for South Asian, Chinese, Black African, and Black Caribbean adults (18.5–22.9). Your GP can also assess your individual health and advise if weight management would benefit you.
What's the difference between stone and kg?
Stone and kilograms are both weight measurements. 1 stone equals 6.35 kg. The UK commonly uses stone and pounds for body weight, whilst kg is standard in medical settings. Our weight converter helps you switch between stone, pounds, and kilograms instantly.
What should I do if I'm worried about my weight?
Speak to your GP, who can assess your health holistically and refer you to NHS weight management services if appropriate. The NHS recommends losing 0.5–1 kg per week for sustainable results, alongside reduced-calorie diet and increased physical activity. Your GP can also check for related health conditions.
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.