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
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15.6 kg in Lbs — Is This a Healthy Weight?
15.6 kg converts to 34.4 lbs in imperial measurements. However, whether this weight is healthy depends entirely on your height. A weight that's healthy for one person could be underweight or overweight for another. The NHS uses BMI (body mass index) as a screening tool to assess if your weight is in a healthy range for your height. Use our free BMI calculator above to check your personal BMI instantly, and see where you fall on the NHS health categories.
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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.
Healthy Weight Ranges at Different Heights
15.6 kg (34.4 lbs) is a very low weight for most adults. To understand if it's healthy for you, we need to consider your height. Here are three real-world examples showing how the same weight produces different health outcomes:
- At 150 cm (4ft 11in): 15.6 kg gives a BMI of 6.9 — this is well below the healthy range and would indicate severe underweight.
- At 165 cm (5ft 5in): 15.6 kg gives a BMI of 5.7 — this is also severely underweight.
- At 180 cm (5ft 11in): 15.6 kg gives a BMI of 4.8 — again, severely underweight.
The healthy weight range for adults varies by height. For example, at 165 cm, the NHS healthy weight range is approximately 49–67 kg. To convert kilograms to stone and see your healthy range, use the weight converter on this page. If your current weight is significantly below the healthy range, speak to your GP about support.
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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 on Healthy Weight and What to Do Next
The NHS defines healthy weight as a BMI between 18.5 and 24.9. If your weight and height put you in a different category — whether underweight, overweight, or obese — your GP can provide personalised advice and support. For South Asian, Chinese, Black African, or Black Caribbean adults, the NHS recommends slightly lower BMI thresholds due to higher health risk at lower weights.
If you're significantly underweight, this can affect bone health, immune function, and energy levels. Waist measurement is also important: men should aim for under 94 cm (37 inches), women under 80 cm (31.5 inches). If you're concerned about your weight — whether too high or too low — contact your GP for guidance and 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.
What does 15.6 kg convert to in stone and pounds?
15.6 kg equals 2 stone 6.1 lbs (or 34.4 lbs). To convert kilograms to stone, divide by 6.35. Use our free weight converter above for instant conversions between metric and imperial units.
Is 15.6 kg a healthy weight for an adult?
It depends on your height. 15.6 kg is very low for most adults and would be severely underweight for anyone over about 130 cm tall. Use our BMI calculator to check your personal BMI and see if your weight is in the healthy range for your height.
What's the healthy weight range in the UK?
The NHS defines healthy weight as BMI 18.5–24.9. For a person who is 165 cm tall, this means a healthy weight is roughly 49–67 kg. Your GP can advise on the healthy weight range for your individual height and health circumstances.
What should I do if I'm significantly underweight?
Contact your GP for support. Being well below the healthy weight range can affect bone health, immunity, and energy. Your GP can assess whether you need nutritional support or investigation into underlying causes.
How is healthy weight different for people from different ethnic backgrounds?
The NHS recommends lower BMI thresholds for South Asian, Chinese, Black African, and Black Caribbean adults because these groups face higher health risks at lower BMI levels. Your GP can advise on appropriate weight ranges for your background and health profile.
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.