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 Is 12.2 Kg In Stone?
At 12.2 kg in stone, you're looking at approximately 1 stone 11.9 pounds — a very low body weight. Your BMI at this weight depends entirely on your height. For most adults, a weight of 12.2 kg would fall well below the healthy weight range and into the underweight category according to NHS guidelines. Use our free BMI calculator above to find your exact BMI by entering your height and weight together.
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.
BMI At 12.2 Kg For Different Heights
12.2 kg converts to 1 stone 11.9 lbs, and your BMI at this weight varies significantly based on your height. Here are example BMI values at different heights for someone weighing 12.2 kg:
- 150 cm (4ft 11in): BMI 5.4 — severely underweight
- 160 cm (5ft 3in): BMI 4.8 — severely underweight
- 170 cm (5ft 7in): BMI 4.2 — severely underweight
- 180 cm (5ft 11in): BMI 3.8 — severely underweight
At any realistic adult height, 12.2 kg represents a dangerously low body weight. If you or someone you know weighs this little, medical advice from your GP is essential. Calculate your personal BMI using the free BMI calculator on this page by entering your exact height.
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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 BMI Categories & When To Seek Help
The NHS BMI categories are: underweight (below 18.5), healthy weight (18.5–24.9), overweight (25.0–29.9), and obese (30.0+). At 12.2 kg, you would be significantly below the underweight threshold regardless of height. Extremely low body weight can indicate malnutrition, eating disorders, or serious illness and requires urgent medical attention. Your GP can assess your individual health, discuss underlying causes, and recommend appropriate support. If you're struggling with eating, body image, or weight concerns, organisations like Beat Eating Disorders (0808 801 0677) provide confidential support.
- 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 12.2 kg to stone and pounds?
To convert 12.2 kg to stone, divide by 6.35029. This gives 1 stone 11.9 lbs (or approximately 1st 12lbs). You can also use our free weight converter above to switch between kg, stone, and pounds instantly.
Is 12.2 kg a healthy weight for an adult?
No. At 12.2 kg, you would be severely underweight at any adult height. The NHS healthy weight range for most adults starts at approximately 50 kg (7st 12lbs) for someone 150 cm tall and increases with height. Please contact your GP for personalised health advice.
What could cause someone to weigh 12.2 kg as an adult?
Severe underweight at this level typically indicates serious underlying issues such as eating disorders, chronic illness, malnutrition, or metabolic conditions. These require urgent medical assessment and support from your GP or a specialist healthcare team.
Why does BMI matter if I'm underweight?
BMI is a screening tool that helps identify health risks at any weight — not just overweight. Being severely underweight carries serious health risks including weakened immunity, bone loss, organ damage, and complications with pregnancy. Your GP can assess your individual situation.
Where can I get support if I'm struggling with my weight?
Start with your GP, who can refer you to appropriate services. If you suspect an eating disorder, contact Beat Eating Disorders (0808 801 0677) or MIND (0300 123 3393). The NHS also offers weight management support through specialist services and community programmes.
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.