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 to Track Weight Effectively for Your Health
Tracking your weight is one of the most effective ways to understand your health and monitor progress towards your goals. Whether you're managing your weight for general wellness, preparing for weight loss treatment, or simply staying aware of changes, regular weight tracking helps you spot trends, stay motivated, and catch any significant changes early. Our free progress tracker makes it simple to log your weight and see your journey over time. This guide explains why tracking matters, how often you should weigh yourself, and how to interpret your results using NHS health guidance.
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.
Why Regular Weight Tracking Matters
Consistent weight tracking provides several health benefits. It helps you establish a baseline for your current health status, which your GP can use to assess whether your weight falls within a healthy range for your height using BMI guidelines. Regular monitoring also helps you detect patterns — for example, whether your weight changes seasonally, fluctuates with your menstrual cycle, or responds to lifestyle changes. This information is invaluable when discussing weight management with your healthcare provider.
If you're considering prescription weight loss medication like Mounjaro (tirzepatide) or Wegovy (semaglutide), your prescriber will want to see your baseline weight and how it changes over time. Tracking also keeps you motivated: seeing progress, even small decreases of 0.5–1 kg per week (the NHS-recommended safe rate), reinforces that your efforts are working. You can use our free weight converter to switch between kg, stone, and pounds, making it easy to understand your weight in whichever units feel most natural to you.
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.
Best Practices for Tracking Your Weight
Weigh yourself weekly — ideally at the same time each week (morning, before eating, after using the bathroom) to minimise normal daily fluctuations. UK health guidance suggests tracking weekly rather than daily, as daily weight naturally varies by 1–2 kg due to water retention, digestion, and hormonal changes. Record consistently — use a notebook, spreadsheet, or our free progress tracker to log your weight each time. This creates a clear record you can share with your GP or prescriber if needed. Expect fluctuations — weight doesn't decrease in a straight line. Plateaus lasting 2–4 weeks are normal and don't mean your efforts aren't working. Track context — note any lifestyle changes (new exercise routine, medication changes, stress levels) that might explain weight shifts. This helps you and your healthcare provider understand what's driving 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.
How often should I weigh myself when tracking weight?
NHS guidance recommends weighing yourself once per week at the same time, ideally in the morning before eating. Daily weighing can be discouraging because weight naturally fluctuates by 1–2 kg due to water retention, food in your stomach, and hormonal changes. Weekly tracking gives you a clearer picture of your actual weight trend without the noise of daily variation.
What's a healthy rate of weight loss when tracking progress?
The NHS recommends losing no more than 0.5–1 kg (1–2 lbs) per week for sustainable, healthy weight loss. This rate is achievable through a moderate calorie deficit and increased physical activity. Faster weight loss is possible with medical support but may increase the risk of muscle loss and nutritional deficiencies.
Should I track weight in kg, stone, or pounds?
Use whichever unit feels most natural to you — UK adults commonly use stone and pounds for body weight. Our free weight converter lets you switch between kg, stone, and pounds instantly, so you can track in your preferred unit. For NHS consultations, your GP may refer to kg, so it's helpful to understand both measurements.
How can I use my weight tracking data with my GP?
Bring your weight records (or a screenshot from our progress tracker) to your GP appointment. This shows your GP the rate and pattern of change, helps them assess your BMI category, and provides context for discussing weight management options. Your prescriber will also find this data useful when assessing your eligibility for prescription weight loss medication.
What if my weight plateaus when I'm tracking?
Weight plateaus (staying the same for 2–4 weeks) are completely normal and don't mean your efforts have failed. Plateaus often occur as your body adjusts to changes. Continue with your current approach, ensure you're maintaining a calorie deficit, stay active, and revisit your progress after another 2–4 weeks. If a plateau lasts longer than 8 weeks, discuss it with your GP.
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.