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 9.4 Lbs (4.26 Kg) a Healthy Weight?
9.4 pounds converts to approximately 4.26 kilograms. Whether this weight is healthy depends entirely on your height — there's no single "ideal" weight that applies to everyone. Using NHS guidelines, we'll show you how to check if this weight falls within a healthy range for your height, and what to do if you're concerned about your weight. Our free BMI calculator above can help you check your personal BMI instantly based on your height and weight.
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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.
Healthy Weight Ranges by Height
A weight of 4.26 kg is extremely light for an adult — it's closer to the weight of a newborn baby or a large dog than a typical adult. For context, average UK adults weigh between 70–90 kg. However, to determine if any weight is healthy, you need to use the BMI formula, which combines weight with height.
Here are three realistic examples showing how height changes what's considered healthy:
- 5ft 4in (163cm): Healthy weight range is 48–64 kg. At 4.26 kg, this would be severely underweight.
- 5ft 8in (173cm): Healthy weight range is 55–75 kg. At 4.26 kg, this would be severely underweight.
- 6ft 0in (183cm): Healthy weight range is 61–82 kg. At 4.26 kg, this would be severely underweight.
If you weigh 4.26 kg and are an adult, it's important to speak with your GP immediately, as this indicates a serious health concern. Use our weight converter to check your weight in stone and pounds — understanding your actual weight in familiar UK units may help clarify any confusion.
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. Your GP can assess your individual weight in the context of your height, age, muscle mass, and overall health. If you're significantly underweight (BMI below 18.5), your GP may investigate causes like thyroid issues, nutritional deficiencies, or eating disorders — all of which are treatable.
Your waist measurement is also important: men should aim for under 94 cm (37 inches), and women under 80 cm (31.5 inches). If you're concerned about your weight, book an appointment with your GP. They can offer personalised advice and support to help you reach a healthier weight range safely.
- 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 9.4 lbs equal in kilograms?
9.4 pounds equals approximately 4.26 kilograms. To convert pounds to kilograms, divide the number of pounds by 2.20462. This is a very light weight for an adult human.
Is 4.26 kg a healthy weight for an adult?
No. At 4.26 kg, this would indicate severe underweight status at any adult height. Healthy adult weight typically ranges from 48 kg to over 100 kg depending on height. If this applies to you, please contact your GP immediately.
How do I check if my weight is healthy for my height?
Use the NHS BMI formula: BMI = weight (kg) ÷ height (m)². A healthy BMI is 18.5–24.9. Use our free BMI calculator above to instantly calculate your BMI — it accounts for both your weight and height to give you personalised context.
What should I do if I'm significantly underweight?
Contact your GP. Severe underweight can indicate malnutrition, thyroid problems, eating disorders, or other medical issues — all of which are treatable. Your GP can assess your health and offer support and guidance tailored to your situation.
How can I convert between pounds, kilograms, and stone?
Use our free weight converter on this page to instantly switch between kg, lbs, and stone. You can also multiply kg by 2.20462 to get pounds, or divide kg by 6.35029 to get stone — helpful for understanding your weight in familiar UK units.
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.