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 BMI Is 27 Kilos in Stone?
27 kilograms is approximately 4 stone 3 pounds. Your BMI at this weight depends entirely on your height — the same weight can fall into different NHS health categories for different people. Use our free BMI calculator above to find your exact BMI instantly, or read on to see example BMI values at common UK heights. This guide explains where your weight sits on the NHS scale and what it means for your health.
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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.
27kg BMI at Different Heights
To convert kilograms to stone, divide by 6.35 — so 27kg equals approximately 4 stone 3 pounds. However, your BMI depends on your height as well as weight. Here are example BMI values at common heights for someone weighing 27kg:
- At 150cm (4ft 11in): BMI of 12 — Underweight (NHS category)
- At 160cm (5ft 3in): BMI of 10.5 — Underweight
- At 165cm (5ft 5in): BMI of 9.9 — Underweight
- At 170cm (5ft 7in): BMI of 9.3 — Underweight
- At 180cm (5ft 11in): BMI of 8.3 — Underweight
At all typical adult heights, a weight of 27kg falls well below the healthy range. This weight may indicate being significantly underweight. Your GP can provide personalised guidance about whether your weight is appropriate for your individual health.
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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 BMI Categories and Limitations
The NHS defines a healthy BMI as between 18.5 and 24.9 for most adults. A BMI below 18.5 is classified as underweight, which can be associated with nutritional deficiencies, weakened immunity, and bone health concerns. However, BMI has limitations — it doesn't distinguish between muscle and fat, and may not be accurate for very short or very tall individuals, athletes, or older adults. For a full weight in stone conversion and to explore your health status, use the weight converter on this page alongside our free BMI calculator for your specific height.
- 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 27kg to stone quickly?
Divide 27 by 6.35 to get stone. 27kg = 4 stone 3 pounds approximately. You can use our free weight converter above for instant conversions between kg, stone, and pounds in both directions.
Is 27kg a healthy weight?
At 27kg, you would be underweight across all adult heights. A healthy weight depends on your height, age, and muscle mass. Use our BMI calculator to check your personal BMI, and speak with your GP if you have concerns about being underweight.
What does underweight mean for my health?
Being underweight (BMI below 18.5) may increase risks of nutritional deficiencies, weakened immune function, and reduced bone density. Your GP can assess whether your weight is appropriate and recommend nutritional support if needed.
How is BMI calculated?
BMI is calculated by dividing weight in kilograms by height in metres squared. The formula is: BMI = weight (kg) ÷ height (m)². Our free BMI calculator on this page does this automatically for you.
Does BMI tell the whole story about weight and health?
BMI is a useful screening tool but has limitations. It doesn't account for muscle mass, where fat is stored, or individual health factors. Your GP can provide a fuller picture of your health alongside your BMI.
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.