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
Half a Stone — UK Weight Conversion and Health Context
Half a stone is a common UK measurement for small weight changes, equal to approximately 3.18 kg or 7 pounds. Understanding this weight in metric terms is useful for tracking progress, following NHS health guidance, or interpreting weight-related health information. Whether you're monitoring a weight loss target or understanding health recommendations, knowing how to convert between UK and metric measurements helps you stay informed about your health.
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 Much is Half a Stone in Kilograms?
Half a stone converts to exactly 3.175 kg (often rounded to 3.18 kg). This uses the standard conversion formula: 1 stone = 6.35029 kg. Half a stone also equals 7 pounds in imperial measurements, making it useful for understanding small weight fluctuations.
For context, half a stone weight loss is considered a meaningful health milestone. According to NHS guidance, losing just 5–10% of body weight can provide significant health benefits including improved blood pressure, better blood sugar control, and reduced joint strain. Our free weight converter above lets you instantly convert between stone, pounds, and kilograms — helpful for tracking progress or understanding clinical measurements.
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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.
Why Half a Stone Matters for UK Health Goals
In UK health discussions, weight changes are often discussed in half-stone increments because it feels achievable and measurable. Losing half a stone (3.18 kg or 7 lbs) typically takes 6–14 weeks at a safe rate of 0.5–1 kg per week, depending on your starting point and approach.
If you're tracking weight loss progress, try our free progress tracker to log changes over time. For personalised health goals, use our BMI calculator to understand your current health status and healthy weight range. Your GP can also provide NHS guidance tailored to your individual circumstances.
- 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 half a stone a good weight loss target?
Yes. Losing half a stone (3.18 kg) is a realistic, achievable milestone. NHS guidance emphasises that even modest weight loss of 5–10% of body weight brings meaningful health benefits including improved blood pressure and reduced cardiovascular risk. Breaking larger goals into half-stone increments makes weight management more manageable.
How long does it take to lose half a stone safely?
At the NHS-recommended safe rate of 0.5–1 kg per week, losing half a stone (3.18 kg) typically takes 6–14 weeks. This depends on your calorie deficit, starting weight, and individual metabolism. Sustainable loss combines a modest calorie reduction with increased physical activity.
What does half a stone weight loss mean for my BMI?
The BMI impact depends on your height and current weight. Use our free BMI calculator to see how half a stone affects your personal BMI. For example, at 5ft 8in, losing half a stone may drop your BMI by approximately 0.5–0.8 points, which could move you into a healthier category.
Can weight loss injections like Wegovy help me lose half a stone?
Weight loss medications like Wegovy (semaglutide) work alongside diet and exercise. Clinical trials show Wegovy helps users lose an average of 15% of body weight over several months — easily exceeding half a stone. However, individual results vary, and prescription is only available following clinical assessment.
How do I track half-stone progress?
Our free progress tracker on this site lets you log weight changes weekly or monthly. You can also use the weight converter to switch between stone, pounds, and kilograms. Regular tracking helps you stay motivated and identify sustainable patterns rather than daily fluctuations.
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.