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 Much Weight Have I Lost — Free Calculator & NHS Guide
Tracking weight loss is a practical way to stay motivated and understand your progress towards a healthier weight. Our free calculator helps you see exactly how much weight you've lost, how your BMI has changed, and whether you're moving towards your ideal weight for your height. Whether you're aiming for an NHS healthy weight range or working with a weight loss programme, knowing your actual progress — not just how you feel — is valuable. Use the BMI calculator on this page to check your current position against NHS guidelines and track meaningful improvements in your health.
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.
What Your Weight Loss Calculator Shows You
A weight loss calculator compares your starting weight with your current weight to show your total loss in kg, stone, or pounds. But the real insight comes from understanding what that loss means for your health. Use our free BMI calculator above to see how your weight change has affected your BMI — moving from obese to overweight, or from overweight into the healthy weight range, is a significant health milestone. The NHS defines a healthy weight range as a BMI between 18.5 and 24.9. If you're of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends a lower range of 18.5 to 22.9. Even a 5–10% reduction in body weight can improve blood pressure, blood sugar control, and reduce joint strain — so tracking progress matters, regardless of how much further you plan to go.
- See your total weight loss in multiple units (kg, stone, lbs)
- Track changes in your BMI over time
- Understand where you sit on the NHS healthy weight scale
- Stay motivated by quantifying real progress
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.
What to Do If You're Still Above Healthy Weight
If the weight for height calculator shows you're still above the healthy weight range, that's valuable information — it means you have a clear target to work towards. The NHS recommends sustainable weight loss of 0.5–1 kg per week through a combination of a reduced-calorie diet and increased physical activity. If you've already lost weight, you've proven you can make changes; consistency matters more than speed. Our progress tracker helps you log ongoing weight changes and spot patterns. If you've lost weight but plateaued, or if you'd like support beyond lifestyle changes, your GP can discuss options including referral to NHS specialist weight management services or, in some cases, prescription weight loss support — but only after a full health assessment.
- 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 do I calculate how much weight I've lost?
Subtract your current weight from your starting weight. If you started at 85kg and now weigh 75kg, you've lost 10kg (1 stone 8lbs). Our free weight converter makes it easy to see the loss in kg, stone, and pounds. The more important figure is your BMI change — use our calculator above to track that.
Is losing 10kg in 3 months a healthy rate?
Yes. That's approximately 0.8kg per week, which falls within the NHS recommendation of 0.5–1kg per week. Sustainable, steady loss is safer than gradual weight management and is more likely to last long-term. Faster loss may include muscle loss alongside fat loss.
What's the ideal weight for my height?
Your ideal weight depends on your individual health, body composition, and fitness level. However, your healthy weight range is based on your BMI: between 18.5–24.9 (or 18.5–22.9 for South Asian, Chinese, Black African, or Black Caribbean adults). Use our BMI calculator with your height to find your personal range in kg and stone.
Will my weight loss show as lower BMI?
Yes. BMI is calculated from your weight and height, so losing weight always lowers your BMI. Moving from 30+ (obese) to 25–29.9 (overweight) or into 18.5–24.9 (healthy weight) is a major health improvement. Track your BMI with our free calculator.
Can I access NHS weight loss support?
Yes. Your GP can refer you to tier 3 NHS specialist weight management services, which may include prescription weight loss medication after full assessment. Waiting times vary by region. Your GP can discuss whether you're eligible based on your BMI and health conditions.
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.