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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Height Percentile Girl Calculator — UK Health Guide
Height percentiles help parents and healthcare professionals understand how a child's growth compares to others of the same age and sex. In the UK, the NHS uses growth reference charts to track children's development from birth through adulthood. A percentile shows the percentage of children who are shorter than your daughter at her age — for example, being on the 50th percentile means half of children her age are taller and half are shorter. Understanding these measurements is part of routine child health monitoring and supports early identification of any growth concerns.
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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.
How Height Percentiles Work in the UK
The NHS uses the UK90 growth reference charts, which are the standard tool for monitoring children's height in the UK. These charts plot height against age and sex, showing percentile lines that represent different growth patterns.
- 50th percentile: Average height for that age group
- 91st percentile: Taller than 91% of children the same age
- 9th percentile: Shorter than 91% of children the same age
- 2nd centile: Below this suggests growth monitoring needed
Growth is measured at every child health appointment, including the Health Visitor checks and school nurse visits. A single measurement tells you where your daughter sits relative to her peers, but what matters more is the growth trend — whether she's following a consistent percentile line or crossing percentiles, which may warrant GP discussion.
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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.
When to Discuss Height with Your GP
Most children naturally grow at their own rate and healthy growth shows consistent progress along a percentile line. However, your GP may want to discuss your daughter's growth if she drops suddenly across percentile lines, remains below the 2nd centile, or shows signs of slower growth than expected for her age.
Factors affecting height include genetics (parental height is the strongest predictor), nutrition, sleep quality, and overall health. If you have concerns about your daughter's growth, your Health Visitor or GP can review her growth chart, assess her wellbeing, and investigate if needed. Early discussion is always better — your NHS GP is your first point of contact for personalised advice about your child's development.
- 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 the average height for a girl in the UK?
Average height varies by age. At age 10, the average UK girl is approximately 140cm (4ft 7in). At age 13, approximately 158cm (5ft 2in). At age 16, approximately 162cm (5ft 4in). These are approximate averages — individual variation is normal and healthy. Your daughter's Health Visitor or GP can show you exactly where she sits on the growth chart.
How often should my daughter's height be measured?
In the UK, height is routinely measured at Health Visitor checks in early childhood, then at school entry and periodically through school nurse visits. If there are any growth concerns, your GP may recommend more frequent monitoring. Between appointments, you can track height at home using a marked doorframe or stadiometer for consistency.
What does it mean if my daughter is on the 75th percentile?
Being on the 75th percentile means your daughter is taller than approximately 75% of girls her age. This is well within the healthy range. The percentile itself is less important than whether her growth is following a consistent pattern over time. As long as she's tracking along her own percentile line steadily, this indicates healthy growth.
Should I be concerned if my daughter is shorter than her peers?
Not necessarily. Height is largely determined by genetics — if you or your partner are shorter, your daughter is likely to be as well. Being shorter than peers is only a concern if growth suddenly slows or drops across percentile lines. Your GP can assess your daughter's overall health, nutrition, and growth pattern to determine if investigation is needed.
How do UK growth charts work differently from other countries?
The UK uses the UK90 growth reference charts, which are based on measurements from UK children and reflect modern UK growth patterns. These charts are more accurate for UK children than older charts or international charts. Your Health Visitor and school nurse use these same charts, ensuring consistent assessment throughout your daughter's childhood.
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