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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15.9 Stone in Lbs — What's Your BMI?
15.9 stone is equivalent to 222.6 pounds (or 101.6 kg). Your BMI at this weight depends entirely on your height — the same weight can give a healthy BMI for a taller person or an obese classification for someone shorter. This guide shows you what BMI this weight produces at different heights, and how it compares to NHS healthy weight thresholds. Use our free BMI calculator above to find your exact BMI instantly, or read on to see where you fall across common UK heights.
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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.
15.9 Stone — BMI at Different Heights
At 15.9 stone (222.6 lbs or 101.6 kg), your BMI varies significantly with height. Here's what this weight means across typical UK adult heights:
- 5ft 4in (163cm): BMI 38.6 — Obese (Class II)
- 5ft 6in (168cm): BMI 36.2 — Obese (Class II)
- 5ft 8in (173cm): BMI 34.1 — Obese (Class I)
- 5ft 10in (178cm): BMI 32.1 — Obese (Class I)
- 6ft 0in (183cm): BMI 30.3 — Obese (Class I)
- 6ft 2in (188cm): BMI 28.7 — Overweight
To convert kilograms to stone and find your personal BMI, enter your exact height into the BMI calculator on this page. Your GP can also discuss what your BMI means for your individual health and whether any lifestyle changes or support would be helpful.
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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 and Healthy Weight
The NHS defines a healthy BMI as 18.5 to 24.9. At 15.9 stone, most adults would fall into the overweight or obese categories depending on height. However, BMI has important limitations — it doesn't distinguish between muscle and fat, so athletes may have a high BMI but low body fat. For people of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends lower BMI thresholds due to higher health risks at the same weight. Use the weight converter on this page to check your weight in different units, and speak to your GP about what a healthy weight range means for you personally.
- 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 many pounds is 15.9 stone?
15.9 stone equals exactly 222.6 pounds (lbs). To convert stone to pounds, multiply the stone value by 14 — since 1 stone = 14 pounds exactly. This conversion is the same for everyone and doesn't change based on health status.
What is 15.9 stone in kilograms?
15.9 stone is equivalent to approximately 101.6 kg. To convert stone to kilograms, multiply by 6.35029. The kg to stone conversion is standard across all weight management and NHS guidance in the UK.
Is 15.9 stone a healthy weight?
Whether 15.9 stone is healthy depends on your height, age, and overall health. For most UK adults, this weight falls into the overweight or obese BMI category. Your GP can assess whether this weight is appropriate for your individual circumstances and discuss any health concerns.
What should I do if my BMI is too high?
If your BMI is above the healthy range, speak to your GP. They may suggest lifestyle changes like balanced nutrition and physical activity. Depending on your BMI and health conditions, your GP might refer you to weight management services or discuss prescription options like GLP-1 medications.
Does muscle weight count differently than fat in BMI?
No — BMI treats all weight the same. This is why BMI has limitations. A muscular person might have a high BMI but low body fat. Your GP can discuss whether BMI is the right measure for you, or whether other assessments like waist circumference would be more helpful.
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.