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 12 Kg Weight Loss?
Losing 12 kg (approximately 1 stone 12 lbs) is a substantial and meaningful weight loss that can significantly improve your health. To put this in context, 12 kg represents around 5–10% of body weight for most adults, which is enough to reduce blood pressure, improve blood sugar control, and lower your risk of weight-related health conditions. Using our free BMI calculator and weight converter above, you can see exactly how this loss would affect your personal health metrics and where it would place you on the NHS weight categories.
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.
How Long Does 12 Kg Weight Loss Take?
The time it takes to lose 12 kg depends on your starting weight, metabolism, and the method you choose. The NHS recommends a safe, sustainable weight loss rate of 0.5–1 kg per week, which means 12 kg would typically take 12–24 weeks (3–6 months).
- At 0.5 kg/week: approximately 24 weeks (6 months)
- At 1 kg/week: approximately 12 weeks (3 months)
- With prescription weight loss medication: may be faster, though individual results vary
A calorie deficit of around 500 kcal per day typically results in 0.5 kg weekly loss. Faster weight loss is possible with medical support such as GLP-1 weight loss injections (like Wegovy or Mounjaro) used alongside reduced-calorie diet and increased physical activity, though prescription weight loss treatment is only available following clinical assessment.
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.
Health Benefits of Losing 12 Kg
Losing 12 kg can have meaningful health benefits, even if your final weight remains in the overweight or obese category. Evidence shows that 5–clinically studied weight loss improves:
- Blood pressure (often a reduction of 5–20 mmHg)
- Blood sugar control and diabetes risk
- LDL cholesterol and triglycerides
- Joint stress and mobility
- Sleep apnoea severity
- Mental health and energy levels
Track your progress with our free progress tracker as you work towards your goal. Your GP can also provide personalised guidance on what this weight loss means for your individual health profile.
- 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 12 kg a lot of weight to lose?
Yes, 12 kg is a significant weight loss equivalent to approximately 1 stone 12 lbs. For most adults, this represents 5–10% of body weight, which is enough to improve blood pressure, blood sugar control, and reduce health risks. Even if you don't reach your goal weight, a 12 kg loss has meaningful health benefits.
How many calories do I need to cut to lose 12 kg?
To lose 12 kg safely at 0.5–1 kg per week, you'd need a calorie deficit of approximately 500 kcal per day. This could be achieved through a combination of reduced food intake and increased physical activity. The exact amount depends on your current weight, metabolism, and age. Your GP or a dietitian can advise on a personalised approach.
Can prescription weight loss medication help me lose 12 kg?
Yes, prescription weight loss medications like Wegovy (semaglutide) and Mounjaro (tirzepatide) are licensed in the UK for weight management. Clinical trials showed average weight loss of 14–21% of body weight with these medications, used alongside diet and exercise. Access is available through NHS specialist services or private prescribing following clinical assessment.
How do I know if losing 12 kg will get me to a healthy BMI?
Use our free BMI calculator above to see your current BMI and what your BMI would be after losing 12 kg. A healthy BMI is between 18.5–24.9 according to NHS guidelines (lower thresholds apply for South Asian, Chinese, Black African, and Black Caribbean adults). Your GP can also advise on what weight range is healthy for you personally.
What's the difference between losing 12 kg and losing weight gradually?
Losing 12 kg over 3–6 months is considered sustainable and safe. Very gradual weight management (more than 1.5 kg per week) increases the risk of muscle loss, nutrient deficiency, and regaining weight. Gradual, steady loss alongside lifestyle changes tends to be easier to maintain long-term and is recommended by the NHS. ```
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.