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
What Is a Healthy BMI for Women?
A healthy BMI for women in the UK falls between 18.5 and 24.9 according to NHS guidelines. Your BMI (body mass index) is calculated using your weight and height, and it provides a quick screening tool for whether your weight is in a healthy range. However, BMI is just one indicator of health — it doesn't account for muscle mass, bone density, or where fat is stored on your body. 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 Ranges and Categories for Women
The NHS BMI categories for women are the same as for men, but it's important to understand what each range means for your health:
- BMI below 18.5: Underweight — may indicate insufficient nutrition or underlying health issues
- BMI 18.5–24.9: Healthy weight — associated with lowest health risks
- BMI 25.0–29.9: Overweight — increased risk of type 2 diabetes and heart disease
- BMI 30.0–34.9: Obese (Class I) — higher health risks requiring GP support
- BMI 35.0–39.9: Obese (Class II) — significant health concerns
- BMI 40.0+: Severely obese (Class III) — serious health risks
If you're of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends lower BMI thresholds: healthy weight is 18.5–22.9, and overweight begins at 23.0. This is because these groups face higher cardiovascular and diabetes risk at lower BMI levels. Calculate your BMI using the standard BMI formula: weight (kg) ÷ height (m)².
Clinically BackedWeight Loss
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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
BMI has important limitations. It doesn't distinguish between muscle and fat — a woman who trains regularly may have a high BMI but low body fat percentage. BMI also ignores where fat is stored; fat around the abdomen carries higher health risks than fat distributed elsewhere. The NHS recommends also measuring waist circumference: increased risk begins above 80cm (31.5 inches), and high risk above 88cm (34.5 inches). Waist-to-height ratio below 0.5 is considered healthy for all women. If you're concerned about your weight or health, your GP can provide personalised advice and consider your full health picture beyond BMI alone.
- 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 formula for women?
The BMI formula is weight (kg) ÷ height (m)². For example, a woman weighing 65kg and 1.65m tall has a BMI of 23.9, which is in the healthy range. Use our free BMI calculator to work this out instantly without a UK pharmacy calculation.
Is healthy BMI the same for women and men?
Yes, the NHS BMI categories are identical for women and men. However, women typically have higher body fat percentages at the same BMI due to biological differences. Individual health depends on factors beyond BMI, including fitness level, waist circumference, and medical history.
Why do women of South Asian or Black African heritage have different BMI thresholds?
Research shows these groups develop type 2 diabetes and cardiovascular disease at lower BMI levels than White European populations. The NHS therefore recommends lower thresholds: healthy BMI is 18.5–22.9 for these groups, with overweight starting at 23.0 rather than 25.0.
Can I be healthy with a BMI above 25?
BMI is a screening tool, not a diagnostic measure. Some women at BMI 25–29.9 are very healthy, especially if they exercise regularly, have good fitness, and low waist circumference. However, this BMI range is associated with increased health risks on average, so your GP can give personalised advice.
What should I do if my BMI is outside the healthy range?
If your BMI is above 24.9, discuss this with your GP, who can assess your overall health, waist measurement, fitness, and any weight-related health conditions. Even modest weight loss (5–10% of body weight) can improve health markers. The NHS recommends a safe weight loss rate of 0.5–1kg per week.
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.