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
How Many Stone Is 40kg?
40kg is equivalent to 6 stone and 4.6 pounds in UK measurements. This weight falls in the underweight category according to NHS BMI guidelines for most adults. Whether you're tracking your weight, following a health plan, or simply need to convert between metric and imperial measurements, understanding your weight in both kg and stone helps you use UK health resources effectively. Our free weight converter above lets you switch between these units instantly, and our BMI calculator can show you what this weight means for your individual 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.
40kg Weight Conversion to Stone
40kg = 6 stone 4.6 pounds (6st 4.6lbs)
To convert kilograms to stone, divide the kg value by 6.35029. For 40kg: 40 ÷ 6.35029 = 6.31 stone. The decimal part converts to pounds: 0.31 × 14 = 4.34 pounds, giving you 6 stone 4.6 pounds.
UK adults commonly use stone and pounds for body weight, while NHS clinical records use kilograms. Both measurements are equally valid—use whichever you find clearer. Our free weight converter above handles this calculation instantly, so you can focus on what matters: understanding your health.
- 40kg in stone: 6st 4.6lbs
- 40kg in pounds only: 88.2 lbs
- Exact conversion factor: 1kg = 0.157473 stone
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 40kg a Healthy Weight?
Whether 40kg is healthy depends entirely on your height and individual circumstances. For an adult who is around 150cm (4ft 11in) tall, 40kg would be in the healthy weight range (BMI approximately 17.8). For someone taller—say 170cm (5ft 7in)—40kg would be underweight (BMI approximately 13.9).
Use our free BMI calculator above to check your personal BMI based on your exact height and weight. The NHS BMI healthy range is 18.5 to 24.9 for most adults, though lower thresholds apply for South Asian, Chinese, Black African, and Black Caribbean adults. If you're concerned about whether your weight is healthy for you, your GP can provide personalised guidance based on your full health picture.
- 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 40kg in stone and pounds?
40kg is equivalent to 6 stone 4.6 pounds (6st 4.6lbs). You can convert any weight using the standard formula: divide kg by 6.35029 to get stone, then multiply the decimal portion by 14 to get the remaining pounds. Our weight converter above does this instantly.
Is 40kg underweight?
It depends on your height. For someone 150cm tall, 40kg is healthy (BMI ~17.8). For someone 170cm tall, it would be underweight (BMI ~13.9). Use our free BMI calculator to check your personal BMI and see where your weight falls according to NHS guidelines.
What is 40kg in pounds only?
40kg equals approximately 88.2 pounds. However, the UK commonly uses stone and pounds together rather than pounds alone. 40kg = 6 stone 4.6 pounds is the standard UK weight expression.
How do I convert 40kg to stone?
Divide 40 by 6.35029 to get 6.31 stone. The decimal part (0.31) multiplies by 14 to give pounds: 0.31 × 14 = 4.34 pounds. So 40kg = 6 stone 4.6 pounds. Use our free weight converter for instant conversions.
Can I use MyWeightCheck tools to track if 40kg is my goal weight?
Yes. Use our free BMI calculator to see what BMI 40kg gives you at your height, and our progress tracker to log changes over time. Our GLP-1 weight loss calculator can also show projected weight changes if you're considering weight management options.
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.