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
Bodyweight Planner — Your UK Health Guide
A bodyweight planner helps you set realistic weight management goals and track progress towards a healthier weight. Whether you're aiming for a specific target or simply want to understand what a healthy weight looks like for your height, planning is essential for sustainable results. Our UK health guide covers everything you need to know about setting achievable goals, understanding your BMI, and monitoring your journey effectively using evidence-based NHS guidance and practical tools.
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.
Understanding Your Healthy Weight Range
Your healthy weight depends on your height, age, and overall health. The NHS uses BMI (Body Mass Index) as the primary screening tool to determine healthy weight ranges. For most adults, a healthy BMI falls between 18.5 and 24.9. However, for people of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends lower thresholds starting at BMI 18.5 to 22.9, as these populations face higher health risks at the same BMI levels.
To find your personal healthy weight range, use our free BMI calculator above to check your current BMI instantly. For a specific target weight based on your height, calculate using the formula: healthy weight = 18.5 to 24.9 × your height in metres squared. Our weight converter tool also helps you translate targets between kg, stone, and pounds to suit your preference.
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.
Setting Realistic Goals and Tracking Progress
Sustainable weight loss occurs at a rate of 0.5 to 1 kg per week, according to NHS guidance. Losing faster can result in muscle loss and isn't sustainable long-term. Start by identifying your current weight and height, then calculate your target BMI range. Break this into smaller milestones — perhaps aiming for a 5–10% reduction in body weight first, which research shows can deliver meaningful health improvements.
Track your progress regularly using our free progress tracker to log weekly or monthly measurements. Monitor not just weight, but also how you feel, energy levels, and any improvements in weight-related health conditions. If you're considering prescription weight loss support, our GLP-1 weight loss calculator can help estimate potential outcomes at different doses alongside lifestyle 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.
What is a realistic bodyweight target?
A realistic target depends on your current height and health status. Use your BMI range (18.5–24.9 for most adults, lower for some ethnic groups) to find your healthy weight window. The NHS recommends losing 0.5–1 kg per week. Aim for a 5–10% reduction first — this often brings measurable health benefits.
How do I use a bodyweight planner effectively?
Set a clear starting weight and target weight based on your healthy BMI range. Break this into smaller monthly goals. Track weekly weigh-ins using our free progress tracker. Record lifestyle changes alongside weight changes. Review progress every 4 weeks and adjust your approach if needed with guidance from your GP.
Should I use a bodyweight planner with weight loss medication?
Yes. If you're taking prescription weight loss medication like Wegovy or Mounjaro, a planner helps track expected progress. Clinical trials show these medications may help achieve 15–clinically studied weight loss on average. Our GLP-1 weight loss calculator estimates potential outcomes when combined with diet and exercise changes.
What if I'm not losing weight as expected?
Weight loss varies between individuals due to genetics, medical conditions, and lifestyle factors. If progress stalls after 4 weeks, review calorie intake, activity levels, and stress. Speak to your GP or a registered dietitian. They can identify barriers and adjust your approach or consider whether prescription weight loss support is appropriate.
How often should I update my bodyweight plan?
Review your plan every 4 weeks. Check whether you're on track for your 0.5–1 kg weekly goal. Celebrate milestones like reaching 5% or clinically studied weight loss. If circumstances change — illness, medication changes, or stalled progress — discuss adjustments with your GP or healthcare team.
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.