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 a Weight Loss Scale and How Does It Help?
A weight loss scale refers to the measurable rate and progression of weight loss over time — not just a bathroom scale, but the broader framework for tracking how much weight you're losing and whether your approach is working. Understanding your personal weight loss scale helps you set realistic goals, monitor progress, and make adjustments to your weight management strategy. The NHS recommends a safe weight loss rate of 0.5 to 1 kg per week for sustainable, long-term results that protect muscle mass and overall health.
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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.
How to Measure Your Weight Loss Progress
Effective weight loss tracking involves more than just checking the scale weekly. Weigh yourself at the same time each day or once a week, preferably in the morning before eating, as weight naturally fluctuates by 1–2 kg throughout the day due to hydration, meals, and hormones. The NHS weight loss guidance emphasises consistency over perfection — small daily fluctuations are normal and don't indicate failure.
- Weekly average: Record your weight for seven days and calculate the average to smooth out daily variations
- Trend over time: Look at your weight loss over 4 weeks rather than individual days — this shows your true progress
- Beyond the scale: Track how clothes fit, energy levels, and how you feel — these are valid measures of progress alongside weight figures
If you're using prescription weight loss medication as part of your weight management UK strategy, your prescriber will typically recommend weigh-ins every 4 weeks during dose adjustments. Our free progress tracker can help you log weight changes, monitor trends, and celebrate milestones throughout your journey.
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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.
Safe Weight Loss Rates and What to Expect
The NHS safe weight loss rate is 0.5 to 1 kg per week, which equates to roughly 2–4 kg per month. This moderate pace allows your body to lose fat rather than muscle, helps you build sustainable habits, and reduces the risk of nutritional deficiencies. Faster weight loss is possible under medical supervision — for example, very low calorie diets (under 800 kcal per day) are sometimes used in specialist settings — but these require close monitoring.
Clinical trials of GLP-1 weight loss injections show average weight loss of 14–20% of body weight over several months, which translates to a more rapid initial loss. However, results vary significantly between individuals, and these medications work alongside reduced-calorie diet and increased physical activity. Our GLP-1 weight loss calculator can help you estimate potential progress at different stages if you're considering prescription weight loss medication. For personalised guidance on your weight loss targets, consult your GP or a registered prescriber.
- 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 often should I weigh myself to track weight loss progress?
Weigh yourself once a week at the same time, preferably in the morning. Daily weighing can be discouraging due to normal fluctuations from water retention and meal timing. The NHS recommends looking at weekly or 4-week trends rather than focusing on individual daily changes, which gives you a clearer picture of actual progress.
What is a realistic weight loss scale per month in the UK?
A safe, sustainable weight loss is 0.5 to 1 kg per week, which means 2 to 4 kg per month. The NHS recommends this pace to protect muscle mass and maintain long-term results. Weight loss medication may support faster initial loss, but individual results vary significantly depending on diet, activity, and personal factors.
Is it normal for weight loss to plateau on the scale?
Yes, weight loss plateaus are completely normal and common. Your body adapts to changes, and progress may slow after initial rapid loss. This doesn't mean your plan isn't working — continue your healthy habits, ensure adequate protein intake, and check that your calorie intake hasn't inadvertently increased. Plateaus usually resolve within 2–4 weeks if you maintain consistency.
Can I use BMI to track my weight loss progress?
Yes, BMI is a useful marker of progress. Calculate your BMI at the start of your weight loss journey and again monthly — watching your BMI move from one category (overweight, obese) to a healthier range (healthy weight) is motivating and clinically meaningful. Use our free BMI calculator to track your BMI changes as you progress.
What should I do if the scale isn't moving despite following my plan?
If weight loss has stalled for more than 4 weeks, review your calorie intake and activity levels with your GP. Some medications can affect weight loss, stress and sleep quality matter, and hormonal factors play a role. If you're considering prescription weight loss medication, speak with a registered prescriber about whether it might support your weight management goals.
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.