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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What Is 27 Lb in Kg? BMI & Health Context
27 pounds is equivalent to 12.25 kilograms. However, knowing your weight alone doesn't tell you much about your health — your height matters too, as this determines your BMI (body mass index). BMI is a screening tool used by the NHS to assess whether your weight falls within a healthy range. Your BMI varies significantly depending on your height, so 12.25 kg could represent anything from underweight to overweight depending on how tall you are. Use our free BMI calculator above to find your personal BMI instantly by entering your weight and height.
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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.
27 Lb (12.25 Kg) BMI at Different Heights
At 12.25 kg, your BMI depends entirely on your height. Here's how this weight converts to BMI at common UK heights:
- 150 cm (4ft 11in): BMI 5.4 — severely underweight
- 160 cm (5ft 3in): BMI 4.8 — severely underweight
- 170 cm (5ft 7in): BMI 4.2 — severely underweight
- 180 cm (5ft 11in): BMI 3.8 — severely underweight
These BMI figures show that 27 lb (12.25 kg) is an extremely low weight for adults of any height. In reality, 27 lb represents a child's weight or the weight loss goal in very specific medical contexts, not a typical adult body weight. The NHS healthy weight range for adults is much higher — typically 50 kg or above depending on height. If you're tracking your own weight, remember to use the weight converter to switch between kg, stone, and pounds for your actual measurements.
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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 & Why Limitations Matter
The NHS categorises BMI as follows: underweight below 18.5, healthy weight 18.5–24.9, overweight 25.0–29.9, obese 30.0 and above. These thresholds apply to all UK adults, though South Asian, Chinese, Black African, and Black Caribbean communities have lower recommended thresholds due to higher health risks at lower BMI levels.
BMI is useful for population screening but has real limitations. It doesn't distinguish between muscle and fat — athletes can have high BMI despite low body fat. BMI also ignores where fat is stored; waist circumference matters too. For personalised advice about whether your weight is healthy, your GP can assess your individual health picture. Try our free weight converter above to track your weight in stone, pounds, or kilograms as you prefer.
- 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.
How do I convert 27 lb to kg accurately?
Multiply 27 by 0.453592. This gives 12.247 kg, or approximately 12.25 kg. Our free weight converter on this page does this instantly. Remember that kilograms (metric) and pounds (imperial) are commonly used in the UK — you may also want to know this weight in stone: 27 lb is roughly 1 stone 13 pounds.
Is 27 lb a healthy weight for an adult?
No. 27 lb (12.25 kg) is extremely low for any adult, regardless of height. It would result in a BMI well below the healthy range at all adult heights. This weight is typical for a young child, not an adult. If you're concerned about your weight, speak to your GP.
What's the healthy weight range in kg for my height?
Healthy BMI range is 18.5–24.9. To find your healthy weight range in kilograms, multiply your height in metres squared by 18.5 (lower limit) and 24.9 (upper limit). For example, at 1.70m tall: lower limit is 53.5 kg, upper limit is 71.9 kg. Use our free BMI calculator above to check your personal healthy range instantly.
How do I convert stone and pounds to kg?
Multiply stone by 6.35029, then multiply pounds by 0.453592, and add the results together. For example, 10 stone 7 pounds = (10 × 6.35029) + (7 × 0.453592) = 66.82 kg. Our weight converter handles this automatically — just enter your weight and select the units.
Why does the NHS use BMI if it has limitations?
BMI is a quick, simple screening tool that works well for population health assessment. However, your GP should consider other factors too, including waist circumference, fitness level, medical history, and family health. BMI is useful guidance but not the whole picture. Always discuss your weight and health with your GP for personalised advice.
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.