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 42kg In Stone?
42 kilograms is equal to 6 stone and 8.1 pounds (6st 8.1lbs). This conversion uses the standard metric to imperial formula where 1 stone equals 6.35029 kilograms. If you need to convert weights regularly between metric and imperial measurements, our free weight converter above makes it instant and accurate. Understanding your weight in both UK and metric measurements is useful for health tracking, NHS guidance, and general UK health information purposes.
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 to Convert 42kg to Stone
To convert 42kg to stone, divide the kilogram figure by 6.35029. In this case: 42 ÷ 6.35029 = 6.62 stone. Breaking this down further: 6 whole stones, plus 0.62 of a stone remaining. Since 1 stone equals 14 pounds, multiply 0.62 × 14 = 8.68 pounds, which rounds to 8.1lbs. The result is 6 stone 8.1 pounds. You can also use the quick conversion: 42kg × 2.20462 = 92.6 pounds total, then divide by 14 to get stone. For regular conversions between kg and stone, the weight converter on this page handles these calculations instantly, saving time and reducing conversion errors.
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.
Is 42kg a Healthy Weight?
Whether 42kg is a healthy weight depends entirely on your height. According to NHS guidance, a healthy BMI falls between 18.5 and 24.9. For example, at 1.65m (5ft 5in), a weight of 42kg gives a BMI of approximately 15.4, which is below the healthy range and may indicate underweight status. At 1.40m (4ft 7in), the same weight gives a BMI of around 21.4, which is within the healthy range. Use our free BMI calculator above to determine whether 42kg is healthy for your specific height and to get personalised health context based on NHS thresholds.
- 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 42kg in stone and pounds?
42kg equals 6 stone 8.1 pounds (6st 8.1lbs). To calculate, divide 42 by 6.35029 to get stone, then multiply the decimal portion by 14 to get the additional pounds. This is the standard UK imperial conversion used across NHS health guidance and UK weight measurement.
How do I convert kilograms to stone quickly?
Divide the kilogram amount by 6.35029 for stone, or multiply by 2.20462 for total pounds. For 42kg: 42 ÷ 6.35029 = 6.62 stone. Use our free weight converter above for instant, accurate conversions between kg, stone, and lbs without a UK pharmacy calculation.
Is 42kg a healthy weight in the UK?
Whether 42kg is healthy depends on your height. According to NHS guidelines, healthy BMI ranges from 18.5 to 24.9. Calculate your personal BMI using our free BMI calculator to see whether 42kg falls within a healthy range for your height and age.
How is stone different from kilograms?
Stone is an imperial unit used primarily in the UK and Ireland; 1 stone equals 6.35kg. Kilograms are metric and used globally for medical measurements. NHS clinical records use kilograms, but UK adults often discuss weight in stone and pounds in everyday conversation.
What weight-related tools can help me track my health?
MyWeightCheck provides several free tools: a BMI calculator to assess healthy weight ranges, a weight converter for metric and imperial switching, a GLP-1 weight loss calculator for understanding weight management options, and a progress tracker to log your health journey over time.
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.