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 for Female — Understanding Your Healthy Weight Range
BMI (Body Mass Index) is a screening tool used by the NHS to assess whether an adult woman's weight falls within a healthy range for her height. Your BMI helps identify if you're at increased health risk, but it's just one part of the picture — other factors like waist measurement and overall fitness also matter. This guide explains the NHS BMI categories, how to calculate your personal BMI, and what the results mean for your health.
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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 BMI categories are the same for all adults regardless of sex, but understanding them is important for women's health planning:
- Underweight: BMI below 18.5 — may indicate nutritional concerns; discuss with your GP if persistent
- Healthy weight: BMI 18.5–24.9 — associated with lower health risk for most women
- Overweight: BMI 25.0–29.9 — increased risk of weight-related conditions
- Obese (Class I): BMI 30.0–34.9 — significantly higher health risk
- Obese (Class II): BMI 35.0–39.9 — very high health risk
- Severely obese (Class III): BMI 40.0+ — severe health risk
For women of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends lower BMI thresholds (healthy range 18.5–22.9) because these groups face higher cardiovascular and diabetes risk at standard BMI levels. The BMI formula is weight (kg) ÷ height (m)², and you can calculate your personal BMI instantly using our free BMI calculator above.
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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 Else Matters for Women's Health
While BMI is useful, it has important BMI limitations: it doesn't distinguish muscle from fat, so athletic women may have a higher BMI but lower health risk. It also doesn't account for where fat is stored — waist circumference is equally important. The NHS recommends women maintain a waist measurement under 80cm (31.5in) for general health, and under 88cm (34.5in) to reduce disease risk. Other measures like blood pressure, cholesterol, blood sugar, fitness level, and family health history all contribute to your overall health picture. If you're concerned about your weight or health, your GP can offer personalised advice beyond BMI alone. You can also track your progress using our free weight loss progress tracker alongside any lifestyle changes.
- 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 range for a woman in the UK?
According to NHS guidelines, a healthy BMI for women is between 18.5 and 24.9. For women of South Asian, Chinese, Black African, or Black Caribbean heritage, the healthy range is 18.5 to 22.9 due to higher health risks at higher BMI levels. Your personal healthy weight range depends on your height — use our free BMI calculator to find yours.
How do I calculate my BMI as a woman?
The BMI formula is weight (kg) divided by height (metres) squared. For example, if you weigh 70kg and are 1.65m tall: 70 ÷ (1.65 × 1.65) = 25.7 BMI. You can calculate this instantly using our free BMI calculator on this page instead of doing it manually.
Does BMI work the same way for women as it does for men?
Yes, the BMI calculation and NHS categories are identical for women and men. However, women typically have higher body fat percentages at the same BMI than men due to biological differences. BMI is a screening tool only — waist measurement and other health markers are equally important for assessing health risk.
What if my BMI is in the overweight range — does that mean I'm unhealthy?
Not necessarily. BMI is a screening tool, not a diagnosis. Many factors affect health including fitness level, muscle mass, blood pressure, cholesterol, and genetics. A higher BMI can indicate increased health risk, but your GP can assess your individual health picture and advise whether lifestyle changes or support would be helpful.
Why do South Asian women have different BMI recommendations?
Research shows that South Asian, Black African, Caribbean, and Chinese populations have higher risk of type 2 diabetes and cardiovascular disease at lower BMI levels compared to white European populations. The NHS therefore recommends lower BMI thresholds for these groups to identify health risk earlier and allow for timely intervention.
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.