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
Understanding Weight Scales for Health Monitoring
A weight scale is a tool that measures your body weight, typically displayed in kilograms, stone, or pounds. Accurate weight measurement is an important part of UK health management and weight tracking. Your weight can fluctuate throughout the day due to hydration, meals, and hormones, so understanding how to use your scale properly helps you monitor your actual progress. Combined with other health information like your BMI, regular weight checks support informed decisions about your health and wellbeing.
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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.
Types of Weight Scales and Accuracy
Bathroom scales are the most common type for home use and typically measure in kilograms or stone and pounds. Digital scales are generally more accurate than mechanical ones, though all scales can drift over time and should be calibrated regularly. Body composition scales estimate body fat percentage using bioelectrical impedance, though these are less precise than clinical methods. For weight management in the UK, a standard digital bathroom scale is usually sufficient for tracking progress.
- Digital scales: typically accurate to ±0.2 kg
- Mechanical scales: less consistent, can drift
- Body composition scales: useful for trends but not clinical-grade accuracy
- Professional scales: used in GP surgeries and clinics for official measurements
Use our free BMI calculator above alongside regular weighing to understand what your weight means for your health according to NHS guidelines. Our weight converter also helps you switch between kg, stone, and pounds instantly.
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.
How to Weigh Yourself Accurately
For consistent measurements, weigh yourself at the same time each day—typically first thing in the morning before eating or drinking. Wear similar clothing or nothing at all, and place your scale on a hard, level surface. Weekly average weight is more meaningful than daily fluctuations, as weight naturally varies by 1–2 kg due to water retention, digestion, and hormonal changes.
- Weigh weekly on the same day and time
- Use a hard, flat surface (not carpet)
- Keep a log to track trends over weeks, not days
- Don't obsess over daily changes—focus on the monthly pattern
For sustainable weight management, combine regular weighing with the GLP-1 weight loss calculator if you're exploring medication options, or use our progress tracker to log your journey alongside diet and activity changes.
- 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.
Why does my weight change so much day to day?
Daily weight fluctuations are completely normal. Water retention, food in your digestive system, hormonal changes, and salt intake can all cause 1–2 kg swings. This is why tracking your weekly or monthly average is more useful than obsessing over daily numbers. Focus on the overall trend rather than single readings.
Are digital scales more accurate than mechanical scales?
Yes, digital scales are generally more accurate and consistent than mechanical scales. Digital scales typically measure within ±0.2 kg. However, all scales can drift over time and should be placed on a hard, flat surface for the most reliable readings. Regular calibration helps maintain accuracy.
What's the best time of day to weigh myself?
The best time is first thing in the morning before eating, drinking, or exercising. This gives the most consistent baseline because your body hasn't consumed food or water yet. Weigh yourself on the same day and time each week for reliable trend data.
Do body composition scales accurately measure body fat?
Body composition scales use bioelectrical impedance to estimate body fat, but they're not clinically accurate. They're useful for tracking trends over time, but individual readings aren't precise. For clinical body fat assessment, speak to your GP or a health professional who uses more advanced methods.
How do I know if my scale is accurate?
Place a known weight on your scale (like a 10 kg dumbbell) to test it. Professional scales in GP surgeries can be used as a reference point. If your home scale shows significantly different readings, it may need calibration or replacement. Digital scales on hard, level surfaces are generally reliable for home weight tracking.
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.