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 is 15 Stone 8 Pounds in Kilograms?
15 stone 8 pounds converts to approximately 99.8 kilograms using the standard UK to metric conversion. This weight is commonly used as a reference point in UK health contexts, where stone and pounds remain the everyday measurement for body weight. Understanding your weight in both metric and imperial units is useful for accessing NHS guidance, using online health guides, and having conversations with your GP about weight management. Our free weight converter above can help you switch between any UK measurements instantly.
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.
UK Health Context for This Weight
At 99.8kg, weight assessment depends entirely on your height, age, and ethnicity. The NHS uses BMI (body mass index) as a screening tool to understand whether a weight falls within a healthy range. For example, if you're 1.75m tall (5ft 9in), a weight of 99.8kg gives a BMI of approximately 32.6, which falls into the obese category according to NHS guidelines. However, for adults 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. Your individual health also depends on where weight is carried (waist measurement matters), muscle mass, and any existing health conditions.
- Use our free BMI calculator above to find your personal BMI instantly
- BMI between 18.5–24.9 is considered healthy by the NHS
- A BMI of 25–29.9 is overweight; 30+ is obese
- Your GP can provide personalised guidance on what your weight means for your health
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.
Taking Action: NHS Guidance and Support
If you're concerned about your weight, the NHS encourages a stepped approach to weight management. This starts with self-help using digital tools and community resources, then progresses to GP-led interventions if needed. Sustainable weight loss is typically 0.5–1kg per week, achieved through a combination of dietary changes and increased physical activity. For some people, prescription weight loss medications may be appropriate following assessment by a healthcare professional. Your GP can discuss what's right for you, including referral to specialist weight management services in your area.
- Aim for gradual, sustainable changes rather than gradual weight management
- Track your progress with our free progress tracker to stay motivated
- Speak to your GP about weight management support available in your area
- 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 15 stone 8 pounds to kilograms?
To convert stone and pounds to kg, use the formula: (stone × 6.35029) + (pounds × 0.453592). For 15st 8lbs: (15 × 6.35029) + (8 × 0.453592) = 95.25 + 3.63 = 99.8kg approximately. Our free weight converter on this page does this instantly for any weight.
Is 99.8kg a healthy weight?
It depends on your height, age, and ethnicity. Use our BMI calculator to find your personal BMI, which the NHS uses to assess whether a weight is in a healthy range. BMI between 18.5–24.9 is considered healthy, though ethnicity affects these thresholds. Your GP can give you personalised advice about your individual health.
What does the NHS recommend for weight management?
The NHS recommends losing weight at 0.5–1kg per week through a combination of dietary changes and increased physical activity. For support, speak to your GP about local weight management programmes, digital resources, or specialist services available in your area.
Does weight tell me everything about my health?
No. While weight is useful, the NHS also considers waist circumference, blood pressure, blood sugar, and cholesterol. Muscle weighs more than fat, so two people at the same weight can have different body compositions. Your GP can assess your overall health picture, not just weight alone.
Should I use a weight loss injection if I weigh 99.8kg?
Prescription weight loss medications like Mounjaro or Wegovy are available for adults with a BMI of 30 or above, or 27+ with weight-related health conditions. Eligibility is assessed individually by a healthcare professional. Speak to your GP about whether you might be suitable for prescription support alongside diet and exercise.
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.