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 Scale for Women: NHS Guidelines and Healthy Ranges
The BMI scale for women works the same way as for men, but NHS guidance emphasises that a healthy BMI range of 18.5 to 24.9 applies universally. However, women of South Asian, Chinese, Black African, or Black Caribbean heritage have recommended lower thresholds (18.5 to 22.9) due to higher health risks at lower BMI levels. Your BMI helps your GP assess weight-related health risks, but it's just one tool — waist circumference and overall fitness also matter. Use our free BMI calculator above to check your personal BMI instantly.
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 for Women
The NHS BMI scale divides adults into five categories based on their BMI range. A BMI below 18.5 is classified as underweight; 18.5–24.9 is healthy weight; 25.0–29.9 is overweight; 30.0–34.9 is obese (Class I); 35.0–39.9 is obese (Class II); and 40.0 and above is severely obese (Class III). These NHS BMI categories apply to most women across the UK. However, the healthy BMI formula reveals an important difference: women of South Asian, Chinese, Black African, or Black Caribbean descent should aim for a healthier BMI range of 18.5–22.9 instead, as clinical evidence shows these groups face increased risk of type 2 diabetes and heart disease at higher BMI levels. Your GP can interpret your personal BMI in context of your age, medical history, and other health markers.
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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 Pathway: When to Seek Help
If your BMI falls into the overweight or obese categories, the NHS recommends starting with lifestyle changes: balanced diet, increased physical activity, and regular monitoring. The NHS weight management pathway has four tiers. Tier 1 involves self-help and community programmes; tier 2 is primary care support from your GP; tier 3 is specialist weight management services (where prescription medications may be considered); and tier 4 is bariatric surgery for severe obesity with serious health complications. Contact your GP if you're concerned about your weight or have overweight BMI threshold health conditions like high blood pressure, type 2 diabetes, or sleep apnoea — they can assess your situation and refer you to appropriate support.
- 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 for women in the UK?
According to NHS guidelines, a healthy BMI for most women is between 18.5 and 24.9. Women of South Asian, Chinese, Black African, or Black Caribbean heritage should aim for 18.5–22.9. Calculate your BMI instantly using our free BMI calculator to see where you fall on the NHS scale.
How is BMI calculated for women?
BMI uses the same formula for everyone: weight in kilograms divided by height in metres squared. For example, a woman weighing 65kg and 165cm tall (1.65m) would have a BMI of approximately 23.9. Our weight converter can help you switch between kg, stone, and pounds easily.
What are the limitations of BMI for women?
BMI doesn't distinguish between muscle and fat, so athletic women may have a higher BMI despite low body fat. Pregnancy, hormonal changes, and bone density also affect BMI accuracy. That's why NHS guidance recommends checking waist circumference (ideal below 80cm for women) alongside BMI.
When should I see my GP about my BMI?
See your GP if your BMI is 25 or above, especially if you have weight-related health conditions like high blood pressure, type 2 diabetes, or sleep apnoea. Your GP can assess your individual situation and discuss whether support or treatment might help.
Does the BMI scale differ for women by age?
No — the NHS BMI scale is the same for all adult women regardless of age. However, older women may lose muscle mass naturally, so your GP may interpret your BMI alongside other health markers like fitness level, waist measurement, and medical conditions.
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.