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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What is 51kg in Stone and Pounds?
51kg converts to 8 stone and 0.2 pounds (or 8st 0lbs) using the standard UK weight conversion. Whether 51kg is a healthy weight depends entirely on your height — the same weight can give a very different BMI for a shorter or taller person. Use our free BMI calculator above to check your personal BMI, or read on to see what 51kg means across different heights and NHS weight categories.
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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.
51kg BMI at Different Heights
At 51kg, your BMI varies significantly depending on height. Here are typical examples:
- At 150cm (4ft 11in): BMI = 22.7 (healthy weight)
- At 155cm (5ft 1in): BMI = 21.2 (healthy weight)
- At 160cm (5ft 3in): BMI = 19.9 (healthy weight)
- At 165cm (5ft 5in): BMI = 18.7 (healthy weight)
- At 170cm (5ft 7in): BMI = 17.6 (underweight)
- At 175cm (5ft 9in): BMI = 16.7 (underweight)
According to NHS guidelines, a healthy BMI falls between 18.5 and 24.9. At 51kg, most adults of average to tall height will fall within the healthy weight range, whilst very tall individuals may be slightly underweight. Use the weight converter on this page to see 51kg in different units, and enter your height into our BMI calculator to get your precise personal BMI.
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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 NHS BMI Categories
The NHS uses standardised BMI ranges to assess weight status. A BMI under 18.5 is classified as underweight, 18.5–24.9 as healthy weight, 25.0–29.9 as overweight, and 30.0 or above as obese. However, BMI has important limitations — it does not distinguish between muscle and fat, so very muscular individuals may have a higher BMI despite being fit and healthy. BMI also does not account for where fat is stored on the body; waist circumference is also relevant to health. 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 BMI. Your GP can provide personalised advice about what your weight means for your individual health.
- 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 is 51kg in stone and pounds?
51kg converts to 8 stone and 0.2 pounds (8st 0lbs) using the standard conversion formula. To kilogram to stone conversion, divide kg by 6.35029. This is a common weight for shorter adults and children approaching adulthood in the UK.
Is 51kg a healthy weight?
Whether 51kg is healthy depends on your height and individual health. For adults aged 150–165cm, 51kg typically falls in the healthy BMI range (18.5–24.9). Taller individuals may be slightly underweight, whilst shorter individuals may be overweight. Use our free BMI calculator to check your personal status.
What BMI does 51kg give at 160cm?
At 160cm (5ft 3in), a weight of 51kg gives a BMI of 19.9, which falls comfortably in the healthy weight range according to NHS guidelines. This is an ideal weight for an adult of this height.
How does 51kg compare to average UK weight?
The average UK adult woman weighs approximately 71.6kg and the average man weighs 85.7kg, so 51kg is significantly below average. However, average weight does not mean healthy weight — your personal BMI and health markers are what matter for your individual health.
Can I use BMI alone to assess my weight?
BMI is a useful screening tool but has limitations. It does not account for muscle mass, bone density, or fat distribution. Waist circumference is also important — the NHS recommends men keep waist circumference below 94cm and women below 80cm. Your GP can give you comprehensive personalised health advice.
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.