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
Is 23 Kilos a Healthy Weight?
23 kilograms is approximately 3 stone 8 pounds — but whether this is a healthy weight depends entirely on your height. For a child or teenager, 23kg may be completely normal; for an adult, it would be considered significantly underweight. This guide explains what 23kg means for your health, shows healthy weight ranges at different heights, and helps you understand your personal weight in stone. Use our free weight converter and BMI calculator above to check your exact measurements and discover where you fall on the NHS healthy weight scale.
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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.
Healthy Weight Ranges by Height
To convert 23 kilos to stone using the standard kilogram to stone conversion, divide 23 by 6.35: this gives approximately 3 stone 8 pounds (or 3.6 stone exactly).
Whether this is healthy depends on your height. The NHS uses BMI (Body Mass Index) to assess healthy weight ranges, which applies the same BMI scale to both kilograms and stone measurements. Here are three realistic examples:
- Adult 155cm tall (5ft 1in): Healthy weight range is 44–59kg (6st 13lbs–9st 3lbs). At 23kg, this would be significantly underweight and require medical attention.
- Adult 165cm tall (5ft 5in): Healthy weight range is 50–67kg (7st 12lbs–10st 7lbs). At 23kg, this would be dangerously underweight.
- Child aged 8–10: 23kg (3st 8lbs) could be entirely normal depending on individual growth patterns. Always use NHS growth charts for children, not adult BMI categories.
Calculate your personal BMI using our free BMI calculator to see exactly where your weight falls.
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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.
Is 23kg Healthy for You?
Being significantly underweight (BMI below 18.5) carries health risks including weakened immunity, bone loss, and nutritional deficiency. If you weigh 23kg and are an adult, this indicates an urgent health concern that requires GP support.
If you're concerned about your weight — whether you think you're too light or too heavy — speak to your GP. They can assess your individual health, consider your age, build, and any underlying medical conditions, and provide personalised guidance. For children and teenagers, NHS growth charts are the appropriate measure, not adult BMI ranges. If you're tracking weight changes over time, use our free progress tracker to log measurements alongside dietary and exercise changes.
- 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 23kg in stone and pounds?
23 kilograms equals 3 stone 8 pounds (or 3.6 stone). To convert kilos to stone and pounds, divide kilograms by 6.35 for stone, then multiply the decimal by 14 for the remaining pounds.
Is 23kg a healthy weight for adults?
For most adults, 23kg would be significantly underweight and a health concern. Healthy weight depends on height and age. An adult at 23kg would typically have a BMI below 18.5. Always consult your GP if concerned about being underweight.
Is 23kg normal for children?
Yes, 23kg (3st 8lbs) is a normal healthy weight for many children aged 8–11, depending on height and individual growth. Use NHS growth charts, not adult BMI categories, to assess children's weight. Your health visitor or GP can advise.
How do I know if my weight is healthy?
Use our free BMI calculator above — it shows your BMI and NHS healthy weight range for your height. A healthy BMI is 18.5–24.9 for most adults. For personalised advice, speak to your GP or health professional.
What should I do if I'm significantly underweight?
If you're underweight (BMI below 18.5), speak to your GP. Causes range from medical conditions to inadequate nutrition. Your GP can investigate and provide support to help you reach a healthier weight safely.
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.