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
What is a Calutor? UK Health Information
A calutor is a digital health calculation tool designed to help you understand your weight, BMI, and overall health status. In the UK, health calculators like those provided by MyWeightCheck are increasingly used alongside NHS guidance to support informed health decisions. Whether you're checking your healthy weight range, converting between stone and kilograms, or exploring weight management options, a calutor provides instant, evidence-based information to help you take the first step towards better health. These tools are particularly useful for understanding whether you might benefit from speaking to your GP about weight management support.
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.
How Health Calculators Support Your Wellness Journey
Health calculators like MyWeightCheck's free tools are built to help you understand your personal health metrics quickly and confidently. Our BMI calculator uses NHS-approved thresholds to show you where your current weight sits on the healthy weight scale — essential information when considering your overall wellness. Meanwhile, our weight converter lets you switch between kg, stone, and pounds instantly, removing the confusion of different measurement systems used in the UK. For those exploring weight loss options, our GLP-1 weight loss calculator helps you understand potential outcomes based on clinical trial data, while our progress tracker lets you log your journey over time. These calculators are informational tools that complement, not replace, advice from your GP — they're designed to empower you with knowledge about your health baseline so you can make informed decisions about next steps.
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.
Using a Health Calculator as Part of Your NHS Health Plan
The NHS encourages UK adults to regularly check their healthy weight range and understand their BMI as part of preventative health care. Using a calutor — whether it's our free BMI calculator or weight converter — gives you a clear starting point for conversations with your GP, especially if you're considering weight management support or prescription options like Mounjaro or Wegovy. Health calculators work best when used alongside lifestyle changes: reduced-calorie diet, increased physical activity, and professional guidance. Remember that individual results vary, and what works for one person may differ for another. If you have any health concerns or your weight significantly impacts your wellbeing, always consult your GP for personalised advice rather than relying on online tools alone.
- 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's the difference between a health calculator and medical advice?
A health calculator is an informational tool that shows you metrics like BMI or weight conversions based on standard NHS formulas. Medical advice comes from your GP or qualified healthcare professional who understands your full health history. Calculators support informed decisions; they don't diagnose or prescribe treatment.
Is using a calutor safe for everyone?
Health calculators are safe for most adults, but they have limitations. BMI calculators don't account for muscle mass or ethnicity-adjusted thresholds, for example. Pregnant women, children, and people with specific medical conditions should consult their GP rather than relying solely on online tools.
How accurate are online weight management calculators?
UK health calculators like MyWeightCheck use evidence-based formulas aligned with NHS guidelines, making them very accurate for their intended purpose — giving you a health baseline. However, individual results vary significantly depending on genetics, lifestyle, and overall health. They're most accurate when used as a starting point, not a final answer.
Can a health calculator help me decide if I need weight loss medication?
A health calculator can show your BMI and help you understand if you might be eligible for weight loss support — but only a prescriber can assess whether medication like Mounjaro or Wegovy is suitable for you. Use our GLP-1 weight loss calculator to understand potential outcomes, then discuss with your GP.
Where should I start if I want to lose weight in the UK?
Start by checking your healthy weight range using a BMI calculator, then speak to your GP. They can refer you to tier 3 NHS weight management services or discuss prescription options if appropriate. Many people benefit from a combination of dietary changes, physical activity, and professional support.
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.