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 18.7kg in Stone?
18.7 kilograms equals 2 stone and 13.3 pounds (2st 13.3lbs) using the standard kilogram to stone conversion. This weight is significantly below the healthy weight range for most UK adults, and medical guidance should be sought if this applies to your personal situation. Use our free weight converter to check conversions between kg, stone, and pounds instantly, and our BMI calculator to understand where this weight sits within health guidelines for your height.
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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.
Conversion Table and Formula
18.7kg = 2 stone 13.3 pounds
To convert kilograms to stone, divide the kilogram value by 6.35029. The formula is: kg ÷ 6.35029 = stone. For 18.7kg: 18.7 ÷ 6.35029 = 2.945 stone (which equals 2 stone 13.3 pounds, since 1 stone = 14 pounds).
Here are nearby values for quick reference:
- 17kg = 2st 9.1lbs
- 18kg = 2st 11.2lbs
- 18.7kg = 2st 13.3lbs
- 19kg = 2st 15.4lbs
- 20kg = 3st 2.5lbs
For precise conversions between any kilogram and stone values, use the weight converter tool on this page to switch between metric and imperial measurements instantly.
Clinically BackedWeight Loss
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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.
BMI and Health Context at 18.7kg
At 18.7kg, BMI depends entirely on height. For an average UK adult height of 170cm (5ft 7in), 18.7kg would give a BMI of approximately 6.5, which is significantly below the healthy range of 18.5–24.9. This weight would indicate severe underweight status and would require medical attention.
If 18.7kg applies to a child or young person, different growth charts apply—always consult your GP or health visitor for paediatric weight concerns. For adults at any weight outside the healthy range, speaking with your GP about personalised health guidance is important. Use our BMI calculator above to check your personal BMI for your actual height and weight.
- 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 18.7kg to stone and pounds?
Divide 18.7 by 6.35029 to get stone (2.945 stone = 2 stone 13.3 pounds). Alternatively, multiply 18.7 by 2.20462 to get pounds (41.2 lbs). Use our free weight converter above for instant conversions between any kilogram, stone, and pound values.
Is 18.7kg a healthy weight?
18.7kg is significantly below the healthy weight range for adults. Whether this weight is of concern depends on your height, age, and individual health. If this is your personal weight, speak with your GP who can assess your health in context and provide appropriate guidance.
What is 18.7kg in just pounds?
18.7kg converts to approximately 41.2 pounds. In UK measurements, this is expressed as 2 stone 13.3 pounds (2st 13.3lbs). The weight converter tool on this page can convert between all three units instantly.
How does 18.7kg compare to average UK weight?
The average UK adult weighs approximately 78kg (men) or 72kg (women)—so 18.7kg is far below average. This weight would be concerning for an adult and would require medical evaluation. For children, weight assessment uses age and sex-specific growth charts, not adult comparisons.
What BMI does 18.7kg give?
BMI at 18.7kg depends on your height. For example, at 170cm (5ft 7in), 18.7kg gives a BMI of about 6.5—severely underweight. Use our free BMI calculator on this page, entering your actual height to see your personal BMI result and health category.
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.