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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Understanding Kg Scales and Weight Measurement in the UK
A kilogram (kg) scale is the standard weight measurement tool used by NHS healthcare professionals across the UK. Unlike the stone and pounds system many UK adults use at home, kilograms provide the precise measurements needed for clinical assessments, BMI calculations, and health monitoring. Understanding how to read and use kg measurements is essential for tracking your health effectively and communicating with your GP about weight-related concerns. This UK health guide explains everything you need to know about kg scales and how they fit into your personal health journey.
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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.
How Kg Scales Work and NHS Guidance
Kilogram scales measure weight in metric units, where 1 kg equals approximately 2.2 pounds or 0.157 stone. The NHS uses kilograms as the standard measurement for all clinical weight assessments, including BMI calculations, medication dosing, and health risk evaluation. This is why your GP will always record your weight in kg on your medical records.
- Digital kg scales offer accuracy to 0.1 kg (100 grams), ideal for tracking small weight changes
- Mechanical kg scales are reliable but less precise than digital versions
- Bathroom scales typically measure in both kg and stone for UK convenience
- Clinical scales used by healthcare professionals measure in kg only
For UK health information, the NHS recommends weighing yourself at the same time each day (morning, after toileting, before eating) for consistent measurements. This consistency helps you and your GP identify genuine weight changes rather than daily fluctuations. To understand what your kg weight means for your health, use our free BMI calculator above to check your BMI instantly.
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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.
Converting Kg and Tracking Your Health
Many UK adults prefer thinking about weight in stone and pounds, so converting your kg measurement is practical for daily use. The weight converter on this page helps you switch between kg, stone, and pounds instantly. However, always use kg when discussing weight with your GP or entering data into NHS health systems.
Regular weight tracking is valuable for health monitoring: Whether you're managing a weight-related health condition, monitoring progress during weight loss, or simply staying aware of your health status, consistent kg scale measurements provide reliable data. Keep a simple log or use our free progress tracker to record your weight monthly. If you notice significant changes (gain or loss of more than 2–3 kg unexpectedly), discuss this with your GP to rule out underlying health issues.
- 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's the difference between kg scales and stone scales?
Kg scales measure weight in kilograms (metric system), while stone scales show weight in stones and pounds (imperial system). The NHS uses kg for all clinical records and health assessments. Most UK bathroom scales display both kg and stone for convenience, but healthcare professionals always work in kg.
How accurate do kg scales need to be for health tracking?
For personal health monitoring, accuracy to 0.5 kg is sufficient. Digital bathroom scales typically measure to 0.1 kg (100 grams), which is excellent for tracking weight changes over weeks and months. Clinical scales used by GPs are calibrated more precisely but the small difference won't affect your personal health tracking.
How often should I weigh myself on a kg scale?
The NHS recommends weighing yourself once a week at the same time of day (morning is best) for accurate tracking. More frequent weighing can cause confusion due to natural daily water and food weight fluctuations. Less frequent weighing makes it harder to spot genuine trends in your weight.
Can I convert my kg weight to stone myself?
Yes — divide your kg weight by 6.35 to get stone, or multiply by 2.2 to get pounds. Alternatively, use our free weight converter on this page for instant conversion between kg, stone, and pounds. Always use kg when discussing weight with your GP or healthcare professionals.
Should I use kg or stone when talking to my GP about weight?
Always use kilograms when speaking with your GP or any healthcare professional. Your medical records, BMI calculations, and medication dosing are all based on kg measurements. Your GP will be familiar with kg values and they ensure accurate health assessments and clinical decisions.
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.