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
Women's BMI: NHS Guidelines & Health Context
Your BMI (body mass index) is a screening tool that helps assess whether your weight is in a healthy range for your height. The NHS uses BMI to identify health risks and guide weight management support. This guide explains the BMI formula, NHS categories, and what different BMI ranges mean for adult women in the UK. Remember that BMI is just one health marker — your GP can provide personalised advice about what your BMI means for you specifically.
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 for Women & Adults
The NHS BMI categories are the same for women and men. Your BMI is calculated by dividing your weight in kilograms by your height in metres squared (BMI = weight ÷ height²). Using the bmi calculator on this page makes this instant and accurate.
The NHS BMI range divides adults into these categories:
- 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 women of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends lower BMI thresholds because these groups face higher cardiovascular and diabetes risk at lower BMI levels. For these communities, healthy weight is BMI 18.5–22.9, and overweight begins at 23.0.
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.
NHS Weight Management & When to Seek Support
If your BMI falls outside the healthy range, the NHS offers support through a structured weight management pathway. Your GP can refer you to tier 1 or tier 2 services for lifestyle support, behaviour change programmes, and advice on diet and physical activity. For BMI over 30 with weight-related health conditions, or BMI over 35, specialist tier 3 weight management services may be available — though access varies by region.
Remember that BMI has limitations — it does not distinguish between muscle and fat, and does not account for where fat is stored around the body. Waist measurement is also important: the NHS recommends women keep waist circumference below 80cm (31.5 inches) to reduce health risk. Your GP can discuss your individual health and what support is right for you.
- 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?
The NHS defines healthy BMI as 18.5 to 24.9 for adult women. For women of South Asian, Chinese, Black African, or Black Caribbean heritage, the healthy range is lower: 18.5 to 22.9. Use the free BMI calculator on this page to find your BMI instantly based on your weight and height.
Is BMI accurate for all women?
BMI is a useful screening tool but has limitations. It doesn't distinguish between muscle and fat — athletes may have high BMI but low body fat. It also ignores where fat is stored. Waist circumference (below 80cm for women) and overall fitness are also important health markers. Your GP can assess your individual health beyond BMI alone.
What should I do if my BMI is over 25?
If your BMI is in the overweight range (25–29.9), your GP may discuss lifestyle changes like improved diet and activity. If your BMI is 30 or above, or 27+ with weight-related health conditions like high blood pressure or type 2 diabetes, you may be eligible for NHS weight management support. Speak to your GP about what services are available in your area.
How is women's BMI different from men's BMI?
The BMI formula and NHS categories are the same for women and men. However, women typically have higher natural body fat percentage (around 25–31% is healthy for women, compared to 18–24% for men), which BMI doesn't capture. This is why BMI should be considered alongside other health factors like waist circumference and overall fitness.
Where can I get personalised BMI advice?
Your GP is the best first point of contact for personalised advice about your BMI and what it means for your health. They can assess your individual circumstances, discuss any weight-related health conditions, and refer you to NHS weight management services if appropriate. You can also use the weight converter on this page to understand your weight in different units.
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.