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 Does 43kg Mean for Your Health in the UK?
43kg is equivalent to 6 stone 11.3 pounds in UK measurements. For most adults, this weight falls within the underweight or lower healthy weight range according to NHS guidelines, depending on height. Understanding where your weight sits on the NHS health scale is important for assessing your overall wellbeing. Use our free weight converter above to see your weight in different units, and our BMI calculator to check where you stand in terms of healthy weight for your specific height.
10,000+ calculations today · NHS-aligned thresholds · 100% free
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.
UK BMI and Healthy Weight Context for 43kg
At 43kg, whether your weight is healthy depends entirely on your height. The NHS BMI calculator uses a healthy weight range of 18.5 to 24.9 BMI across UK adults. For example, someone who is 160cm (5ft 3in) tall at 43kg would have a BMI of approximately 16.8, which falls in the underweight category. Conversely, someone who is 150cm (4ft 11in) tall at 43kg would have a BMI of around 19.1, which is within the healthy weight range.
The NHS recommends using the BMI calculator on this page to check your personal BMI instantly. For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, NHS guidance suggests using adjusted BMI thresholds, with a healthy range of 18.5 to 22.9. Being significantly underweight can pose health risks including weakened immunity, bone health concerns, and nutritional deficiencies, so it's important to discuss any weight concerns with your GP.
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 When to Seek Advice
If you are 43kg and concerned about whether this weight is appropriate for your health, your GP can provide personalised advice based on your individual circumstances, medical history, and family background. The NHS offers free health guidance through your local practice. Weight that falls outside the healthy range—either significantly underweight or overweight—may require lifestyle support or further assessment.
You can also use our free progress tracker to monitor your weight over time and identify trends. If you have concerns about nutritional intake, energy levels, or general health at this weight, arrange an appointment with your GP for a proper health check and tailored advice.
- 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 is 43kg in stone and pounds?
43kg converts to 6 stone 11.3 pounds (or 6st 11lbs when rounded). Use the weight converter on this page for instant conversions between kg, stone, and lbs.
Is 43kg a healthy weight for an adult?
Whether 43kg is healthy depends on your height and ethnic background. Use the BMI calculator above to check your personal BMI. For most adults over 160cm tall, 43kg may be underweight. Always consult your GP for personalised health advice.
What BMI is 43kg?
A BMI of 43kg depends on your height. At 160cm, it's approximately 16.8 (underweight). At 170cm, it's approximately 14.9 (underweight). At 150cm, it's approximately 19.1 (healthy). Use our BMI calculator to find your exact BMI.
What does underweight mean according to the NHS?
The NHS defines underweight as a BMI below 18.5. While some people are naturally slim, being significantly underweight can affect bone health, immunity, and energy levels. Discuss any concerns about low weight with your GP.
Where can I get NHS health advice about my weight?
Your GP offers free, confidential health guidance. Ring your local practice to book an appointment. The NHS website (nhs.uk) also provides free health information and weight management resources for UK residents.
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.