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 21 Stone in Pounds?
21 stone (21st) equals 294 pounds (294 lbs) exactly. In kilograms, this converts to approximately 132.5 kg. If you're checking your weight or comparing UK and imperial measurements, our free weight converter above makes it simple to switch between stone, pounds, and kilograms instantly. Understanding your weight in different units helps when reading NHS health guidance or discussing your health with your GP, as medical records may use metric measurements while everyday UK conversations often use stone and pounds.
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.
NHS Health Context for 21 Stone
At 21 stone (132.5 kg), understanding your health context is important. According to NHS guidelines, healthy weight ranges depend on your height and individual health factors. Use our free BMI calculator above to find out where your weight sits within NHS categories—this gives you a clearer picture of your personal health status than weight alone. For reference, the NHS considers a BMI of 30 or above to fall within the obese category, which may qualify adults for weight management support through the NHS if other health conditions are present. Even modest weight loss of 5–10% can bring meaningful health benefits including improved blood pressure, better blood sugar control, and reduced joint strain.
- NHS weight management services available through your GP via tier 3 specialist referral
- Regional variation in access—waiting lists differ across England, Scotland, Wales, and Northern Ireland
- Safe weight loss rate: 0.5–1 kg per week for sustainable results
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.
UK Health Support and Resources
If you're considering weight management, your GP is your first point of contact for personalised advice. The NHS Healthy Weight Programme offers free information and digital tools to support sustainable lifestyle changes. For those who may benefit from prescription weight management support, GPs can refer eligible adults to specialist services, where medications and structured programmes are available. You can also track your progress using our free progress tracker, which helps you monitor weight changes alongside lifestyle improvements and gives you clear data to discuss with your healthcare team.
- Start with your GP for a confidential health assessment
- NHS provides free weight management resources online
- Specialist services available if referred by 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 convert 21 stone to pounds?
Simply multiply 21 by 14, since one stone equals exactly 14 pounds. 21 × 14 = 294 pounds. You can also use our free weight converter on this page to switch between stone, pounds, and kilograms instantly.
What is 21 stone in kilograms?
21 stone equals approximately 132.5 kg. To convert, multiply 21 by 6.35029 (the conversion factor for stone to kilograms). This metric measurement is what you'll typically see in NHS health records and medical documentation.
Is 21 stone a healthy weight?
Whether 21 stone is healthy depends on your height, age, sex, and overall health. Use our BMI calculator above to find your personal BMI and NHS category. Your GP can provide individualised advice about what's healthy for you, considering your complete health picture.
What health support is available at 21 stone in the UK?
If you're interested in weight management, your GP can assess your eligibility for NHS support, including tier 3 specialist services and prescription weight management options. The NHS offers free programmes, and regional variation means access differs across England, Scotland, Wales, and Northern Ireland.
How much weight loss would improve my health?
The NHS evidence shows that even losing 5–10% of your body weight can bring meaningful benefits—lower blood pressure, improved blood sugar, reduced joint pain, and better sleep. At 21 stone, a 5–10% loss equals roughly 7–14 pounds. Your GP or a specialist service can help you set realistic, sustainable goals.
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.