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
Is a BMI of 23 Good?
Yes, according to NHS guidelines, a BMI of 23 is considered a healthy weight. It falls comfortably within the recommended healthy BMI range of 18.5 to 24.9 for most UK adults. This means you're at lower risk of weight-related health conditions such as type 2 diabetes, heart disease, and high blood pressure. However, BMI is just one indicator of health — your overall fitness, diet, and lifestyle also matter significantly. Use our free BMI calculator to check your personal BMI and understand where you sit within the NHS healthy weight range.
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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 What Your Score Means
The NHS BMI range for healthy weight is 18.5 to 24.9. A BMI of 23 sits firmly in the middle of this range, indicating a healthy weight for most adults. According to NHS guidance, maintaining a BMI within this healthy range significantly reduces your risk of developing weight-related health conditions.
The full NHS BMI categories UK are:
- Below 18.5 = Underweight
- 18.5–24.9 = Healthy weight (where your BMI of 23 falls)
- 25.0–29.9 = Overweight
- 30.0–34.9 = Obese (Class I)
- 35.0–39.9 = Obese (Class II)
- 40.0+ = Severely obese (Class III)
It's important to note that BMI limitations exist — BMI does not account for muscle mass, bone density, or where fat is stored on your body. Athletes, for example, may have a higher BMI due to muscle but still be very healthy. Your GP can provide personalised guidance about what your BMI means in the context of your individual health. For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends slightly lower healthy thresholds (18.5–22.9), as these groups face higher health risks at the same BMI level.
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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.
NHS Weight Management Support and Next Steps
If your BMI is 23, you're already within the healthy weight range and don't require NHS weight management intervention. However, the NHS recommends everyone maintain a healthy lifestyle through regular physical activity and a balanced diet to keep your weight stable. If you're concerned about your weight or health, your GP remains your first point of contact — they can assess your individual risk and discuss any lifestyle goals.
The NHS weight management pathway typically supports people with a BMI of 30 or above, or 27–29.9 with weight-related health conditions. Since you're in the healthy range, focus on maintaining your current weight through sustainable habits rather than further weight loss. Consider tracking your progress using our free progress tracker to monitor your weight stability over time and identify any trends early.
- 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 a BMI of 23 considered overweight?
No. A BMI of 23 is well within the NHS healthy weight range of 18.5–24.9. It is not overweight. The overweight BMI threshold begins at 25.0. Your BMI of 23 indicates you're at a healthy weight for your height.
What does BMI formula calculate exactly?
The BMI formula is weight (kg) divided by height (m) squared. It estimates body fat based on height and weight only, giving a screening indicator of whether your weight falls in a healthy range. BMI doesn't distinguish between muscle and fat, so it's one tool among many for assessing health.
Can I use a BMI calculator to check my exact BMI?
Yes. Our free BMI calculator on this page instantly calculates your BMI when you enter your weight and height. It also shows you exactly where you fall within the NHS BMI categories and provides context for your personal healthy weight range.
What should I do if I have a BMI of 23?
If your BMI is 23, you're in the healthy weight range. Continue with balanced nutrition, regular physical activity, and regular health check-ups with your GP. Maintaining your current weight through sustainable habits is the goal — avoid extreme dieting or unnecessary weight loss.
Are there any BMI limitations I should know about?
Yes. BMI doesn't account for muscle mass, bone density, body composition, or where fat is stored. Athletes may have high BMI but low body fat. Pregnant women, elderly people, and very muscular individuals may have misleading BMI scores. Your GP can provide context specific to your 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.