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's the Average BMI for a Woman in the UK?
The average BMI for UK adult women is approximately 27.4, which falls into the overweight category according to NHS guidelines. However, average BMI does not tell you what's healthy for you personally. The NHS defines a healthy BMI range as 18.5 to 24.9 for most women, though for women of South Asian, Chinese, Black African, or Black Caribbean heritage, the recommended range is lower at 18.5 to 22.9. Understanding your individual BMI and what it means for your health is far more useful than population averages. Our free BMI calculator above can show you your personal BMI instantly and where it sits on the NHS scale.
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
The NHS uses a standardised BMI formula to classify weight ranges: BMI = weight (kg) ÷ height (m)². According to NHS guidance, adult women fall into these categories:
- Below 18.5 — Underweight
- 18.5 to 24.9 — Healthy weight
- 25.0 to 29.9 — Overweight
- 30.0 to 34.9 — Obese (Class I)
- 35.0 to 39.9 — Obese (Class II)
- 40.0+ — Severely obese (Class III)
If you're of South Asian, Chinese, Black African, or Black Caribbean heritage, your BMI risk thresholds are lower because these groups face higher risks of type 2 diabetes and cardiovascular disease at the same BMI levels. For these groups, the healthy range starts at 18.5 but reduces to 22.9 for overweight classification to begin at 23.0. NICE and NHS guidance emphasise this ethnic variation because one-size-fits-all BMI categories can miss important health risks in these populations.
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 Support and When to Seek Help
If your BMI sits above the healthy range, the NHS offers support through a structured weight management pathway. Most women start with Tier 1 self-help resources — including the free NHS Weight Loss Plan, digital tools, and community programmes. If BMI is 30 or above, or 27–29.9 with weight-related health conditions such as type 2 diabetes, high blood pressure, or sleep apnoea, your GP can refer you to Tier 3 specialist weight management services. These services may include dietary support, activity advice, and prescription weight loss medications — though waiting lists vary significantly by region. Your GP is the best starting point to discuss your personal BMI and what support may help 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.
Is an average BMI of 27.4 for UK women healthy?
No — average does not mean healthy. The NHS defines healthy BMI as 18.5–24.9. At 27.4, the UK female average falls into the overweight category. However, individual health depends on many factors beyond BMI, including where weight is distributed, fitness level, and medical history. Your GP can assess what's healthy for you personally.
How do I calculate my personal BMI as a woman?
Use the standard BMI formula: weight (kg) ÷ height (m)². Our free BMI calculator on this page does this instantly — just enter your height and weight in kg or stone. It will show you your BMI and which NHS category you fall into, plus your healthy weight range for your height.
Should women aim for a lower BMI than men?
No — the NHS BMI categories are the same for women and men (18.5–24.9 is healthy for both). However, women typically carry a higher percentage of body fat at the same BMI due to biological differences, so some argue women may benefit from slightly lower BMI targets. Discuss what's appropriate for you with your GP.
What's the difference between BMI and body fat percentage?
BMI measures weight relative to height but doesn't distinguish between muscle and fat. Body fat percentage directly measures the proportion of fat in your body. Someone athletic may have a high BMI but low body fat. BMI is useful for population screening but has limitations at the individual level — your GP can help interpret your results.
Can I use the BMI formula to calculate my healthy weight range?
Yes. For a given height, multiply your height (m)² by 18.5 and by 24.9 to find your healthy weight range in kg. For example, at 1.65m tall, healthy weight is 50–67kg (7st 12lbs–10st 7lbs). Use our weight converter to switch between kg, stone, and lbs for easier reference.
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.