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
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11.9 Lbs to Kg — What's Your BMI?
11.9 lbs equals approximately 5.4 kg. However, your BMI depends on your height as well as weight, so a single weight figure doesn't tell you whether you're in a healthy range. This guide shows what BMI 11.9 lbs gives at different heights, using NHS weight categories. Use our free BMI calculator above to check your personal BMI instantly.
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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.
11.9 Lbs to Kg at Different Heights — BMI Examples
11.9 lbs = 5.4 kg exactly. To convert pounds to kilograms, divide by 2.20462. However, this weight alone is very light for most adults — BMI depends on both weight and height together.
Here's what BMI 11.9 lbs (5.4 kg) gives at common UK heights:
- At 5ft 2in (157cm): BMI 19.5 — Healthy weight range (NHS)
- At 5ft 4in (163cm): BMI 18.8 — Healthy weight range (NHS)
- At 5ft 6in (168cm): BMI 18.2 — Healthy weight range (NHS)
- At 5ft 8in (173cm): BMI 17.6 — Healthy weight range (NHS)
- At 5ft 10in (178cm): BMI 17.0 — Healthy weight range (NHS)
This weight sits in the healthy range across all heights. For context on whether this is right for you, our free weight converter can help you see this weight in stone and pounds too.
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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 BMI Categories and What They Mean
According to NHS guidelines, a healthy BMI is between 18.5 and 24.9 for most adults. At 11.9 lbs (5.4 kg), the examples above show this weight falls within the healthy range across typical adult heights.
However, BMI has limitations — it doesn't account for muscle mass, bone density, or where fat is stored. Very athletic individuals with high muscle may have a higher BMI but still be healthy. Your GP can give you personalised advice about what your BMI means for your individual health. For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends lower BMI thresholds, as these groups face higher health risks at lower BMI levels.
- 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 11.9 lbs in kilograms?
11.9 lbs equals 5.4 kg. To convert any weight from pounds to kilograms, divide the number of pounds by 2.20462. This is the standard metric to imperial weight conversion used across the UK NHS and health services.
Is 11.9 lbs a healthy weight?
Whether 11.9 lbs (5.4 kg) is healthy depends entirely on your height and age. For most adults, this weight would be very light. Use our BMI calculator above to check whether this weight is in the healthy range for your specific height.
How do I convert between kg, stone, and pounds?
Use our free weight converter to switch between metric and imperial measurements instantly. 1 kg = 0.157 stone, and 1 stone = 14 pounds exactly. So 5.4 kg = 0.85 stone = 11.9 lbs.
What does BMI stand for?
BMI stands for Body Mass Index. It's calculated as weight (kg) divided by height (metres) squared. The NHS uses BMI as a screening tool to categorise whether adults are underweight, healthy weight, overweight, or obese. However, BMI doesn't account for muscle mass or fat distribution.
Should I be concerned about being 11.9 lbs?
This depends on your height and overall health context. At very light weights, your GP may want to check your nutritional health and rule out underlying conditions. If you have concerns about your weight, ask your GP for personalised guidance rather than relying on BMI alone.
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.