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
Setting Realistic Weight Loss Goals in the UK
Setting achievable weight loss goals is the foundation of sustainable weight management. Rather than aiming for rapid results, the NHS recommends losing weight at a steady pace of 0.5 to 1 kg per week, which is both safe and maintainable long-term. Your goal should be based on your current weight, height, and overall health — not on unrealistic targets or comparison to others. This guide explains how to set meaningful weight loss goals aligned with NHS guidance and your personal circumstances.
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 Starting Point and Target Range
Before setting a weight loss goal, you need to know your current position and understand what constitutes a healthy weight for your height. Use our free BMI calculator above to check your starting point — this gives you a baseline for setting targets. For most UK adults, a healthy BMI is between 18.5 and 24.9. However, for adults of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends a lower threshold of 18.5 to 22.9.
To calculate your healthy weight range: multiply your height in metres by itself, then multiply by 18.5 (lower bound) and 24.9 (upper bound). For example, at 1.73m (5ft 8in), a healthy weight range is approximately 55 to 74 kg (8st 10lbs to 11st 10lbs). Our weight converter can help you switch between kg and stone easily. Your goal should fall within this range rather than aiming for a specific number that may not be realistic or healthy for your body.
- Calculate your BMI to establish your starting point
- Identify your healthy weight range based on height and ethnicity
- Use the weight converter to express targets in your preferred units (stone, lbs, or kg)
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.
Safe Weight Loss Rates and Realistic Timelines
The NHS recommends losing no more than 0.5 to 1 kg (1 to 2 lbs) per week for sustainable results. This pace reduces muscle loss, minimises nutritional deficiencies, and helps you develop lasting habits. Faster weight loss is possible with medical support — for example, some GLP-1 weight loss medications used in NHS weight management services or through private prescription can support faster initial loss alongside dietary changes. However, even with medication, individual results vary significantly.
To estimate timelines: if you need to lose 10 kg at a rate of 0.5 kg per week, expect roughly 20 weeks (5 months). Setting a goal of losing 5–10% of your current body weight over 3–6 months is realistic and evidence-based. Even modest weight loss delivers meaningful health benefits — reduced blood pressure, improved blood sugar control, and lower joint stress. Track your progress using our free progress tracker to stay motivated and adjust your approach if needed.
- 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 weight loss goal for me?
A realistic goal is typically 5–10% of your current body weight over 3–6 months. For example, if you weigh 90 kg, losing 4.5–9 kg is achievable and delivers measurable health benefits. Your GP can help you set personalised targets based on your age, health conditions, and medical history.
How quickly should I aim to lose weight?
The NHS recommends losing 0.5 to 1 kg per week for safe, sustainable results. Faster loss is possible with medical support, but individual results vary. Aim for steady progress rather than rapid change — this protects muscle mass and builds lasting habits.
Should my weight loss goal be based on BMI or appearance?
Your goal should be based on achieving a healthy BMI range and improving health markers (blood pressure, blood sugar, fitness) rather than appearance alone. Use our BMI calculator to check your target range. Your GP can advise on health-focused goals that matter most for your circumstances.
What if I'm not losing weight at the NHS-recommended rate?
Weight loss varies between individuals due to genetics, medications, hormones, and other factors. If you're not progressing after 4–6 weeks, discuss this with your GP. They may review your diet, activity level, or explore weight management support — including prescription medication like GLP-1 injections if appropriate.
Can prescription weight loss medication help me reach my goals faster?
Yes — prescription weight loss medications like Mounjaro (tirzepatide) and Wegovy (semaglutide) may support faster weight loss alongside a reduced-calorie diet and physical activity. Our GLP-1 weight loss calculator can help you estimate potential results at different doses. However, medications are only prescribed following clinical assessment by a licensed prescriber, and suitability varies individually.
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.