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 Does 15.6 Kg Give You?
15.6 kg converts to approximately 34.4 lbs in imperial measurements. However, your BMI depends entirely on your height. At 15.6 kg, you would fall into different NHS BMI categories depending on how tall you are. Use our free BMI calculator above to find your personal BMI instantly, or read on to see example BMI values at different heights and what they mean for your health according to NHS guidelines.
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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.
15.6 Kg BMI At Different Heights
At 15.6 kg, here are example BMI values for common adult heights using the BMI formula (weight in kg ÷ height in metres squared):
- At 150 cm (4ft 11in): BMI 6.9 — significantly underweight
- At 160 cm (5ft 3in): BMI 6.1 — significantly underweight
- At 170 cm (5ft 7in): BMI 5.4 — significantly underweight
- At 180 cm (5ft 11in): BMI 4.8 — significantly underweight
- At 190 cm (6ft 3in): BMI 4.3 — significantly underweight
At this weight, regardless of height, you would fall well below the NHS healthy weight range of BMI 18.5–24.9. If this applies to you, it's important to speak with your GP about whether your weight is healthy for your individual circumstances, as being significantly underweight can also have health implications.
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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 And Limitations
NHS BMI categories are: underweight (below 18.5), healthy weight (18.5–24.9), overweight (25–29.9), obese (30–34.9), and severely obese (40+). However, BMI has important limitations — it does not distinguish between muscle and fat, nor does it account for where fat is stored on the body. For people of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends lower BMI thresholds due to higher health risks at lower weights. Waist circumference and overall health context matter too. Use our free weight converter and BMI calculator together to understand your personal health picture, and always discuss your weight with your GP for personalised guidance.
- 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 15.6 kg convert to in stone and pounds?
15.6 kg is approximately 2 stone 6.4 lbs (or 2.46 stone) using the metric to imperial weight conversion. You can convert kilograms to stone by dividing by 6.35029. At this weight, you would be significantly underweight regardless of height according to NHS standards.
Is 15.6 kg a healthy weight?
15.6 kg is significantly below the NHS healthy weight range for any adult. Healthy weight depends on height, but at 15.6 kg even the tallest adults would have a BMI well below the healthy range of 18.5–24.9. If you weigh this much, speak with your GP to discuss your individual health.
How do I convert kg to stone accurately?
To convert kilograms to stone, divide the kg amount by 6.35029. For example, 15.6 kg ÷ 6.35029 = 2.46 stone. Our free weight converter on this page does this instantly. You can also convert to pounds: 15.6 kg × 2.20462 = 34.4 lbs.
What factors affect whether a weight is healthy?
Health at any weight depends on height (which determines BMI), age, muscle mass, where fat is stored, ethnicity, and overall health conditions. BMI is a useful screening tool but has limitations. Waist circumference, fitness level, and blood pressure also matter. Your GP can assess what's healthy for you personally.
Where can I check my personal BMI?
Use our free BMI calculator above — enter your weight in kg or lbs, your height in cm or feet and inches, and get your instant BMI result with NHS category. The calculator works for any weight and height, and shows which NHS healthy weight range applies to you.
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.