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's A Healthy Weight For A 14-Year-Old Girl In The UK?
There is no single "perfect" weight for a 14-year-old girl in kilograms — healthy weight varies significantly based on height, frame size, genetics, and stage of development. The NHS recommends using age and sex-specific growth charts rather than adult BMI categories. A GP or school nurse can assess whether your daughter's weight is healthy for her individual circumstances using UK health guidance and personalised advice.
10,000+ calculations today · NHS-aligned thresholds · 100% free
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.
NHS Guidance On Healthy Weight For Teenage Girls
The NHS does not use BMI categories for children and young people — instead, healthy weight is assessed using UK90 growth reference charts, which account for age, sex, and individual development stage. These charts show the normal range of weights for children at each age.
- A weight below the 2nd centile may indicate being underweight
- A weight between the 2nd and 91st centiles is considered a healthy range
- A weight above the 91st centile may suggest being overweight
- A weight above the 98th centile may indicate obesity
At 14 years old, girls are still developing, and weight gain during adolescence is normal and healthy. A GP, school nurse, or practice nurse can plot your daughter's weight on the correct growth chart to show whether she is tracking normally for her age and height.
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No appointments. No waiting rooms. Just care — from a UK-regulated online pharmacy.
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.
Supporting Healthy Weight During Teenage Years
Rather than focusing on achieving a specific weight, the emphasis during adolescence should be on building healthy habits. Encourage regular physical activity, balanced nutrition, and positive relationships with food. The NHS recommends that children and young people get at least 60 minutes of moderate activity daily and eat a varied diet including fruits, vegetables, whole grains, and protein sources.
If you have concerns about your daughter's weight, growth, or development, speak with your GP or school nurse. They can provide personalised UK health guidance and rule out any underlying medical conditions. MyWeightCheck provides a free BMI calculator for reference, but individual assessment by a healthcare professional is essential for young people.
- 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.
Should a 14-year-old girl use the adult BMI calculator?
No. Adult BMI categories do not apply to children and teenagers. The NHS uses age and sex-specific growth reference charts (UK90) instead. Ask your GP or school nurse to assess your daughter's weight using the correct growth chart for her age. These tools account for normal development and variation during adolescence.
What is an average weight for a 14-year-old girl in the UK?
Average weight varies widely based on height and development stage. At 14, UK girls typically weigh between 40–65 kg, but this varies significantly. The NHS growth charts show the full normal range. Your daughter's weight is healthy if she is tracking consistently on her growth curve, regardless of the specific number.
Is rapid weight gain normal for a 14-year-old girl?
Yes, weight gain during puberty and adolescence is completely normal. Girls often gain weight and height rapidly during their teenage years. What matters is that growth is steady and follows her individual growth curve. If weight gain seems excessive or your daughter has other health concerns, speak with your GP.
When should I be concerned about my daughter's weight?
Speak with your GP if your daughter's weight changes dramatically, if she seems unwell, or if her growth pattern changes significantly. Signs of concern include gradual weight management, extreme weight gain despite normal eating, or if she shows signs of an eating disorder. Your GP can assess her health properly and provide UK health guidance.
How can I support healthy weight in a teenage girl without focusing on numbers?
Focus on health, not weight. Encourage regular activity she enjoys (sports, walking, dancing), eat family meals together, avoid restrictive dieting, and model positive attitudes to food and body image. The NHS recommends balanced nutrition and at least 60 minutes of daily activity. Growth and weight changes during adolescence are normal and healthy.
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.