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
How Much Is 40kg in Stone?
40kg is equivalent to 6 stone and 5 pounds (6st 5lbs) in UK measurements. This straightforward conversion uses the standard metric-to-imperial formula that the NHS and UK health services recognise. Whether you're checking a weight listed in kilograms or need to understand UK health guidance, converting between units is essential for making sense of health information. This guide explains the conversion, how it relates to UK health recommendations, and provides context for where this weight sits within NHS healthy weight ranges.
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.
40kg Conversion and UK Health Context
The exact conversion: 40kg ÷ 6.35029 = 6.305 stone, which equals 6 stone and 4.3 pounds (often rounded to 6st 5lbs for practical purposes). You can instantly convert any weight using our free weight converter above.
In NHS health guidance, weight alone tells only part of the story — height matters equally. A weight of 40kg may be healthy, underweight, or overweight depending on your height and individual circumstances. For example, 40kg at 150cm (4ft 11in) gives a BMI of approximately 17.8 (healthy weight), but 40kg at 180cm (5ft 11in) gives a BMI of around 12.3 (underweight by NHS standards). Use our free BMI calculator above to check where your personal weight sits within NHS healthy weight ranges.
- 40kg is considerably below the UK adult average (men: ~85.7kg, women: ~71.6kg)
- This weight is typical for adolescents, smaller adults, or individuals following medical weight loss guidance
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.
When 40kg May Be Appropriate and UK Support
40kg may be a healthy weight for shorter adults, typically those under 155cm in height, or for adolescents depending on age and development. The NHS emphasises that healthy weight is individual — it depends on height, age, sex, muscle mass, and overall health.
If you're aiming for weight management or have concerns about whether your weight is healthy, your GP is the best starting point. They can assess your individual circumstances, discuss your health goals, and signpost you to NHS weight management support if needed. This might include access to tier 1 digital tools, tier 2 community programmes, or specialist tier 3 services depending on your needs and location.
Track your weight progress over time using our free progress tracker, and refer back to the weight converter and BMI calculator as your weight changes.
- 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.
Is 40kg a healthy weight?
Healthy weight depends on height, age, and individual factors — not weight alone. 40kg may be healthy for shorter adults (typically under 155cm) but underweight for taller people. Your BMI and GP assessment matter more than the number itself. Use our BMI calculator above to check your personal context.
What is 40kg in pounds?
40kg equals approximately 88 pounds (88lbs). To convert, multiply kilograms by 2.20462. Our free weight converter above lets you switch between kg, stone, and pounds instantly.
How does 40kg compare to UK average weight?
40kg is considerably below UK adult averages. The average UK adult man weighs about 85.7kg and the average woman about 71.6kg. However, averages don't determine what's healthy for you — your height, age, and overall health are more important.
Should I be concerned if I weigh 40kg?
Not necessarily, but it depends on your height and health. If 40kg is a significant change or you have concerns, speak to your GP. They can assess whether your weight is appropriate for your height and discuss any health goals you have. NHS weight management services can also provide support.
What NHS guidance applies to a weight of 40kg?
The NHS uses BMI as a screening tool alongside other health measures. At 40kg, your BMI depends entirely on your height. The NHS also considers ethnicity — South Asian, Chinese, and Black African or Caribbean adults have different risk thresholds. Your GP can explain what your weight means for your health.
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.