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
Free Weight Loss Calculator In Stone And Pounds
A weight loss calculator in stone and pounds helps UK adults understand their current weight, target weight, and potential progress using familiar measurements. This guide covers prescription weight management options available in the UK, including eligibility criteria and how to access treatment through the NHS or private prescribing. Whether you're exploring medication support alongside lifestyle changes or want to understand your weight loss potential, we'll help you navigate the options and next steps with your GP.
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.
UK-Licensed Prescription Weight Loss Medication Options
Three prescription weight loss medications are currently licensed for weight management in UK adults:
- Mounjaro (tirzepatide) — a once-weekly injection, dual GIP and GLP-1 receptor agonist. In clinical trials, participants lost an average of 15–21% of their body weight over 72 weeks alongside reduced-calorie diet and increased physical activity.
- Wegovy (semaglutide) — a once-weekly GLP-1 injection. Clinical trial data showed average weight loss of approximately 15% of body weight at the maximum dose.
- Saxenda (liraglutide) — a once-daily GLP-1 injection, typically effective for weight management in eligible adults.
All three are prescription-only medicines requiring clinical assessment. Use our GLP-1 weight loss calculator to estimate potential weight loss projections at different doses, and our weight converter to track progress in stone and pounds.
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.
Eligibility And NHS Vs Private Access
You may be eligible for prescription weight loss medication if you have a BMI of 30 or above, or BMI of 27–29.9 with a weight-related health condition such as type 2 diabetes, high blood pressure, or cardiovascular disease. For South Asian, Chinese, Black African, or Black Caribbean adults, lower thresholds apply.
NHS access: Referral through your GP to specialist tier 3 weight management services. Availability varies significantly by region.
Private access: Online consultation with a UK-licensed prescriber, prescription dispensed by GPhC-registered pharmacy. Available without NHS referral.
Check your current BMI using our free BMI calculator above, then discuss options with your GP.
- 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 my weight loss goal in stone and pounds?
Identify your current weight in stone and pounds using our free weight converter. Set a realistic target (usually 5–clinically studied weight loss initially). Use our weight loss calculator to estimate potential progress with medication support. Track changes using our progress tracker to monitor weekly or monthly improvements in stone and pounds.
Am I eligible for prescription weight loss medication on the NHS?
NHS eligibility typically requires a BMI of 30 or above, or 27–29.9 with weight-related health conditions like diabetes or hypertension. Lower BMI thresholds apply for certain ethnicities. Speak to your GP about referral to specialist weight management services. Availability varies by region and waiting times can be lengthy.
What's the difference between Mounjaro and Wegovy for weight loss?
Mounjaro (tirzepatide) is a dual GIP and GLP-1 receptor agonist; Wegovy (semaglutide) is GLP-1 only. Clinical trials show Mounjaro produced slightly higher average weight loss (15–21% vs ~15%). Both are once-weekly injections. Individual results vary significantly. A prescriber will assess which is more suitable based on your health profile.
Can I access weight loss medication privately without NHS referral?
Yes. Private online consultations with UK-licensed prescribers can lead to prescription weight loss medication if clinically appropriate. Prescriptions are dispensed by GPhC-registered pharmacies. Costs range from approximately £129–£320 monthly depending on dose and provider. This route typically offers faster access than NHS waiting lists.
Should I use a weight loss calculator before speaking to my GP?
Yes. Using a free weight loss calculator helps you understand your current BMI, target weight in stone and pounds, and potential progress with medication support. This information supports informed conversations with your GP about eligibility, NHS options, or private access. Combine calculator insights with lifestyle planning for best results.
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.