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 Does a BMI of 34 Mean?
A BMI of 34 falls into the obese (Class I) category according to NHS guidelines. This means your weight carries increased health risks, but the good news is that even modest weight loss of 5–10% can significantly improve your health outcomes. Understanding your BMI is an important first step, but it's just one part of the picture. Your GP can give you personalised advice about what your individual BMI means and what options are available to support you.
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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.
BMI 34 and NHS Health Categories
A BMI of 34 places you in the obese (Class I) category according to the NHS BMI formula and health guidelines. The NHS BMI range shows that obesity begins at 30.0 and Class I obesity extends from 30.0 to 34.9.
- Healthy weight range: BMI 18.5 to 24.9
- Overweight: BMI 25.0 to 29.9
- Obese (Class I): BMI 30.0 to 34.9 — this is where a BMI of 34 falls
- Obese (Class II): BMI 35.0 to 39.9
- Severely obese (Class III): BMI 40.0 and above
If you're of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends lower thresholds — obesity may begin at BMI 27.5 for your ethnic group. Use our free BMI calculator above to confirm your exact BMI and see where you fall within these ranges.
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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
While BMI is a useful screening tool, it has important limitations. A BMI of 34 doesn't distinguish between muscle and fat — athletes or very muscular individuals may have a high BMI but low body fat. BMI also doesn't account for where fat is stored, which affects health risk. Your waist circumference is equally important: for men, increased risk begins at 94cm (37in), and for women at 80cm (31.5in).
Other measures like your blood pressure, blood sugar, cholesterol levels, and overall fitness matter too. Your GP can assess these alongside your BMI using our free weight converter and BMI calculator to create a personalised health picture and discuss what support options might work for 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.
What health risks are associated with a BMI of 34?
A BMI of 34 increases your risk of type 2 diabetes, heart disease, high blood pressure, certain cancers, sleep apnoea, and joint problems. However, losing even 5–10% of your body weight can reduce these risks significantly. Your GP can assess your individual risk profile based on your age, family history, and other health factors.
How much weight would I need to lose to reach a healthy BMI?
This depends on your height. For example, at 5ft 7in (170cm), a BMI of 34 corresponds to roughly 80kg — reaching a healthy BMI of 24.9 would require losing to around 63kg. Use our free BMI calculator above to calculate the healthy weight range for your specific height.
Is BMI the only thing I should consider for my health?
No. While BMI is useful, your waist circumference, blood pressure, cholesterol, blood sugar, fitness level, and overall lifestyle matter too. A GP can assess all these factors together to give you a complete picture and discuss options like lifestyle changes, dietary support, or prescription medications if appropriate.
Can I lose weight and improve my health from a BMI of 34?
Yes, absolutely. Even modest weight loss of 5–10% can improve blood pressure, blood sugar control, cholesterol, joint pain, and sleep quality. The NHS recommends losing 0.5–1kg per week for sustainable results. Your GP can discuss different approaches — diet, exercise, behaviour support, or prescription weight loss options depending on your individual circumstances.
Should I see my GP about a BMI of 34?
Yes, it's worth having a conversation with your GP. They can assess your overall health, discuss any weight-related symptoms or health conditions you have, and explore whether lifestyle support or treatment options might help. There are now several approaches available, including NHS-funded services in some areas and private options if you wish to explore them.
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.