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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5.4 Lbs in Kg — What's Your BMI?
5.4 lbs is equal to approximately 2.45 kg. However, your BMI — the key measure of healthy weight — depends on both your weight and height. This guide shows what BMI this weight gives you at different heights, where it falls in NHS categories, and how to use our free BMI calculator to check your personal health context. Whether you're tracking weight loss, understanding metric to imperial conversions, or checking where you stand on the healthy weight scale, this information is designed to help.
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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.
5.4 Lbs (2.45 Kg) BMI at Different Heights
A weight of 5.4 lbs (2.45 kg) is relatively light and would only give a meaningful BMI in very short individuals. Here's what this weight converts to at various heights:
- At 4ft 6in (137 cm): BMI = 13.0 — healthy weight (NHS category)
- At 4ft 10in (147 cm): BMI = 11.3 — underweight
- At 5ft 2in (157 cm): BMI = 9.9 — underweight
- At 5ft 6in (168 cm): BMI = 8.7 — underweight
- At 6ft 0in (183 cm): BMI = 7.3 — underweight
These figures illustrate why BMI is calculated as weight divided by height squared — the same weight produces very different results depending on height. Use our free BMI calculator above to enter your own height and see your personal BMI instantly, along with your NHS category.
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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.
Understanding Your BMI Category and Limitations
According to NHS guidelines, a healthy BMI for adults falls between 18.5 and 24.9. A BMI below 18.5 is classified as underweight, which can carry health risks including weakened immunity and bone density loss. However, BMI has important limitations — it doesn't distinguish between muscle and fat, doesn't account for where fat is stored, and may be less accurate for elderly people or very athletic individuals. For a complete picture of your health, your GP may also check your waist circumference and other health markers. Use our free weight converter above to switch between kilograms, stone, and pounds for clarity.
- 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 5.4 lbs converted to kilograms?
5.4 lbs equals approximately 2.45 kg. The conversion formula is: lbs × 0.453592 = kg. So 5.4 × 0.453592 = 2.45 kg. This small weight is often seen in medical contexts — for example, newborn weight or small medication doses.
Is a BMI based on 5.4 lbs considered healthy?
At this weight, BMI depends entirely on height. For very short adults (under 4ft 8in), this weight might fall in the healthy range. For most adults, this weight would indicate being significantly underweight. Your GP can assess whether your weight is healthy for your individual circumstances.
How do I calculate my BMI if I weigh 5.4 lbs?
BMI = weight (kg) ÷ height (m)². At 2.45 kg and, for example, 1.7m tall, your BMI would be 2.45 ÷ (1.7)² = 0.85. However, this is not a realistic adult weight. Use our BMI calculator on this page to check your actual BMI with accurate measurements.
What does underweight BMI mean for health?
An underweight BMI (below 18.5) can indicate malnutrition, weakened immunity, or bone health concerns. If your BMI is underweight, speak to your GP who can assess your individual health and may refer you to a dietitian for personalised nutrition advice.
Should I use stone and pounds or kilograms for my weight?
In the UK, both are used — many people find stone and pounds more familiar, whilst the NHS uses kilograms clinically. Our weight converter above lets you switch between kg, stone, and lbs instantly. Use whichever feels most natural to you for tracking.
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.