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
BMI Chart in Stones — NHS Categories and Health Thresholds
A BMI chart in stones helps UK adults understand their weight health using familiar measurements. The NHS provides clear BMI categories that apply whether you measure in kilograms, stones, or pounds. Your BMI (body mass index) is calculated from your height and weight, and the NHS uses standardised ranges to indicate healthy weight, overweight, and obesity categories. This guide explains what those ranges mean and how to interpret your own BMI using stone measurements.
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 BMI Categories and What They Mean
The NHS BMI formula divides your weight in kilograms by your height in metres squared — but the result is the same whether you measure in stones or kilograms. According to NHS guidance, the standard BMI categories are:
- Underweight: BMI below 18.5
- Healthy weight: BMI 18.5–24.9
- Overweight: BMI 25.0–29.9
- Obese (Class I): BMI 30.0–34.9
- Obese (Class II): BMI 35.0–39.9
- Severely obese (Class III): BMI 40.0 and above
For adults of South Asian, Chinese, Black African, or Black Caribbean backgrounds, the NHS recommends lower thresholds — a healthy BMI range of 18.5–22.9 is advised, as these populations face higher cardiovascular and diabetes risk at standard thresholds. Use our free BMI calculator above to find your personal BMI instantly in any unit.
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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.
NHS Weight Management and When to Seek Help
The NHS has a structured weight management pathway to support adults concerned about their weight. If your BMI falls outside the healthy range, your GP can discuss your individual health picture, assess any weight-related conditions like type 2 diabetes or high blood pressure, and recommend appropriate support. This may include lifestyle programmes, NHS weight loss resources, or referral to specialist tier 3 weight management services. The NHS emphasises that BMI limitations exist — BMI does not account for muscle mass, bone density, or where fat is stored — so your GP will always consider your full health context alongside BMI. Even a 5–10% reduction in body weight can deliver meaningful health improvements.
- 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 is a healthy BMI in stones?
A healthy BMI is 18.5–24.9 according to NHS guidelines. For example, at 5ft 8in (1.73m), a healthy weight is roughly 8st 10lbs to 11st 10lbs. For South Asian, Chinese, Black African, or Black Caribbean adults, the NHS recommends a lower healthy range of 18.5–22.9. Use our BMI calculator to check your personal healthy range instantly.
How do I convert my weight in stones to BMI?
Convert your weight from stones to kilograms (multiply by 6.35029), then apply the BMI formula: weight (kg) ÷ height (m)². Our free BMI calculator does this instantly — simply enter your height and weight in any unit, and it displays your BMI and NHS category immediately.
What should I do if my BMI is above 30?
If your BMI is 30 or above, speak with your GP. They can assess your individual health, discuss any weight-related conditions, and recommend support — which may include lifestyle changes, weight loss programmes, or specialist referral. The NHS offers free resources including the NHS Weight Loss Plan and access to tier 3 specialist services in some areas.
Are there different BMI thresholds for different ethnicities?
Yes. The NHS recommends lower BMI thresholds for adults of South Asian, Chinese, Black African, and Black Caribbean heritage. For these groups, a healthy BMI is 18.5–22.9 (instead of 18.5–24.9), and overweight starts at 23.0, because these populations have higher risk of type 2 diabetes and cardiovascular disease at standard thresholds.
What are the limitations of using a BMI chart?
BMI does not distinguish between muscle and fat — athletes may have a high BMI but low body fat. BMI also ignores where fat is stored (abdominal fat is higher risk), doesn't account for age-related muscle loss, and is less accurate during pregnancy. Your GP can assess these factors and provide personalised health advice alongside BMI measurement.
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.