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 a Good BMI for a Woman?
A good BMI for a woman is between 18.5 and 24.9 according to NHS guidelines. However, the exact healthy BMI range depends on your ethnicity, age, and overall health. For most UK women, this range equates to roughly 50–70 kg depending on height. Your GP can give you personalised advice about what a healthy weight means for you. 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 for Women
According to NHS guidelines, BMI categories for women are:
- 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
To find your BMI, divide your weight in kilograms by your height in metres squared using the standard BMI formula. For example, a woman who is 1.65m tall with a healthy weight of 65kg would have a BMI of 23.9 — well within the healthy BMI range UK guidelines. If you're not sure how to calculate it, our free calculator on this page does it instantly. Remember that even small variations in weight can move you between categories, so focus on sustainable health rather than hitting an exact number.
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.
Important Limitations of BMI for Women
BMI limitations are especially important for women to understand. BMI does not distinguish between muscle and fat — so athletic women or those with high muscle mass may have a higher BMI but low body fat. BMI also doesn't account for where fat is stored; waist circumference matters more for heart health than BMI alone. For women of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends lower healthy BMI thresholds starting at 18.5–22.9, as these groups face higher health risks at standard BMI levels. Age also matters — muscle naturally decreases with age, so your ideal weight may change. Your GP can assess your individual health using BMI alongside other measures like blood pressure and cholesterol.
- 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 BMI should a woman aim for?
The NHS recommends a healthy BMI of 18.5–24.9 for most women. However, ethnicity, age, and individual health conditions affect what's healthy for you personally. Your GP can give you personalised guidance based on your full health picture, not just BMI alone.
How do I calculate my BMI as a woman?
Divide your weight in kilograms by your height in metres squared. For example: 65 kg ÷ (1.65 × 1.65) = 23.9 BMI. Use our free BMI calculator above to check yours instantly without doing the maths manually.
Is BMI different for women and men?
No — the BMI formula and categories are the same. However, women typically have a higher natural body fat percentage than men (21–24% is considered fitness level for women vs 14–17% for men), so comparable BMI may look different visually between genders.
What should my weight be if my BMI is healthy?
A healthy weight depends entirely on your height. Use our free weight converter to see what different BMI values mean in your height range. For example, at 5ft 5in (165cm), a healthy BMI of 18.5–24.9 equals roughly 50–67kg or 7st 12lbs to 10st 7lbs.
Should I focus on BMI or waist measurement?
Both matter. BMI is a screening tool, but waist circumference is also important — the NHS recommends women keep waist measurements below 80cm (31.5 inches) for reduced health risk. Your GP can advise on the best measures to track for your individual health.
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.