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 UK Health Calculators for Weight Management
Health calculators are simple, evidence-based tools that help you understand your current weight, BMI, and overall wellness. Whether you're tracking your progress or exploring weight management options, calculators provide personalised insights aligned with NHS guidance. MyWeightCheck offers free health calculators designed specifically for UK adults, including BMI assessment, weight conversion between stone, pounds, and kilograms, and GLP-1 weight loss projections. These tools are informational only—always consult your GP for personalised health advice.
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.
Why UK Health Calculators Matter
Health calculators are evidence-based tools that interpret your measurements against NHS thresholds and clinical guidelines. The BMI calculator assesses whether your weight falls within a healthy range for your height, accounting for ethnicity-adjusted thresholds where appropriate. Our weight converter translates between UK measurements (stone and pounds) and metric (kilograms)—essential since NHS records use kilograms while many UK adults naturally think in stone. A GLP-1 weight loss calculator helps you explore potential outcomes of weight management medications like Mounjaro or Wegovy, based on clinical trial data. These tools support informed conversations with your GP and help you track progress throughout your wellness journey. Regular monitoring using calculators can motivate sustained lifestyle changes and early identification of health risks.
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.
How to Use MyWeightCheck Calculators
Using our calculators is straightforward: enter your current measurements (weight in stone/pounds or kilograms, height in feet/inches or centimetres) and the tool instantly provides your BMI category, healthy weight range, and relevant NHS health advice for your circumstances. If you're interested in weight management options, our GLP-1 calculator shows potential outcomes based on your starting weight and the medication dose. All results include context about limitations—BMI doesn't account for muscle mass, for example. Results are private, stored locally on your device, and never shared. MyWeightCheck also includes a progress tracker so you can log measurements over time and visualise trends. For personalised guidance beyond calculators, always speak with your GP about uk health information specific to your medical history.
- 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.
Are health calculators accurate?
Health calculators are screening tools based on clinical guidelines and population averages—not diagnostic devices. BMI is useful but has limitations; it doesn't distinguish muscle from fat or account for ethnicity-related health differences. Our calculators are aligned with NHS thresholds and clinical trial data, but individual variation is significant. Always discuss results with your GP for personalised interpretation and advice.
Why does MyWeightCheck use both stone and kilograms?
UK adults traditionally use stone and pounds for body weight, while NHS clinical records use kilograms. Our calculators support both because many people think in stone but need to understand their measurements in metric for NHS documents and medication dosing. Conversion between units is seamless on our weight converter tool.
Can calculators help with weight loss planning?
Yes. MyWeightCheck calculators support weight loss planning by showing your BMI category, healthy weight range, and potential outcomes of evidence-based weight management approaches. Our GLP-1 weight loss calculator models results from clinical trials. These tools help you set realistic goals and track progress, but should always be used alongside GP advice and lifestyle changes—not instead of them.
Is my data safe when I use these calculators?
Yes. MyWeightCheck calculators are private and secure. Your measurements are processed locally on your device and are not stored on our servers or shared with third parties. You can use our tools anonymously without creating an account.
When should I speak to my GP instead of using a calculator?
Use calculators for screening and motivation, but consult your GP if you have concerns about your weight, experience rapid weight changes, have underlying health conditions, or want to discuss weight management medications. Your GP can provide personalised advice that calculators cannot replace.
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.