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
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Women's BMI: Understanding Your Healthy Weight Range
Women's BMI (Body Mass Index) is a measurement of body weight relative to height, used by the NHS to assess whether an adult woman is at a healthy weight. A healthy BMI for women falls between 18.5 and 24.9 according to UK guidelines. However, BMI is just one health screening tool — it doesn't account for muscle mass, bone density, or where fat is stored on your body. Understanding your personal BMI range and what it means for your health is an important part of health awareness. Use our free BMI calculator above to check your personal BMI instantly and see where you fall on the NHS scale.
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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 Healthy Ranges for Women
The NHS uses standardised BMI categories that apply equally to women and men. Your BMI is calculated using the formula: weight (kg) divided by height in metres squared. A healthy BMI range of 18.5 to 24.9 is associated with lower health risks for most women. However, ethnicity matters — women of South Asian, Chinese, Black African, or Black Caribbean heritage have higher cardiovascular and diabetes risks at lower BMI levels, so the NHS recommends lower healthy thresholds: 18.5 to 22.9.
- Underweight: BMI below 18.5
- Healthy weight: BMI 18.5–24.9 (or 18.5–22.9 for South Asian/Black African/Caribbean/Chinese women)
- Overweight: BMI 25.0–29.9
- Obese Class I: BMI 30.0–34.9
- Obese Class II: BMI 35.0–39.9
- Severely obese: BMI 40.0 and above
To find your healthy weight range for your height, multiply your height in metres squared by 18.5 (lower bound) and 24.9 (upper bound). You can also use our weight converter to switch between kg, stone, and pounds to understand these ranges in your preferred units.
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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.
BMI Limitations and What Really Matters for Women's Health
While BMI is a useful screening tool, it has important limitations. BMI does not distinguish between muscle and fat — athletic women or those with significant muscle mass may have a high BMI despite low body fat. It also doesn't show where fat is stored; waist circumference is equally important for health assessment. The NHS recommends women measure their waist: over 80cm (31.5 inches) indicates increased health risk, over 88cm (34.5 inches) indicates high risk. Age, hormonal changes, pregnancy, and bone density also affect what a healthy BMI means individually. Your GP can provide personalised advice about whether your BMI is healthy for you and recommend lifestyle changes or further assessment if needed.
- 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 the healthy BMI range for women in the UK?
The NHS recommends a healthy BMI of 18.5–24.9 for most women. For women of South Asian, Chinese, Black African, or Black Caribbean heritage, the recommended healthy range is lower: 18.5–22.9. These lower thresholds reflect higher cardiovascular and diabetes risk at lower BMI levels in these populations.
How is BMI calculated for women?
BMI is calculated using the formula: weight in kilograms divided by height in metres squared. For example, a woman weighing 65kg and 1.65m tall would have a BMI of 24 (65 ÷ 1.65²). Our free BMI calculator does this instantly — just enter your weight and height in your preferred units.
Why does BMI differ for women of certain ethnic backgrounds?
Research shows that women of South Asian, Chinese, Black African, and Black Caribbean heritage face higher risks of type 2 diabetes and heart disease at lower BMI levels than white European women. The NHS therefore recommends lower BMI thresholds (18.5–22.9 instead of 18.5–24.9) for these groups to prompt earlier health assessment.
What are the limitations of using BMI for women?
BMI doesn't distinguish between muscle and fat, so athletic women may have high BMI despite healthy body composition. It also ignores where fat is stored — waist circumference is equally important. BMI is less accurate during pregnancy, perimenopause, and in older age due to muscle and bone changes.
Should I be concerned if my BMI is outside the healthy range?
A BMI outside the healthy range may indicate increased health risk, but it's not a diagnosis. Consult your GP, who can assess your overall health, family history, fitness level, and waist circumference to give personalised advice. Lifestyle changes like balanced nutrition and physical activity often help, and your GP can discuss options if needed.
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.