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 Calculator UK — What Your Measurements Mean
Understanding where your height falls in relation to the wider UK population is important for assessing whether growth and development are on track. A height percentile calculator uses NHS growth reference data to show how your or your child's height compares to others of the same age and sex. This free UK health guide explains what percentiles mean, how they're used in NHS practice, and how they relate to your overall health context.
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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
Height percentiles are used across NHS services to track growth and development. A percentile is a ranking out of 100 — if you're on the 50th percentile, your height is typical for your age and sex; above the 95th percentile means you're taller than 95% of your peer group; below the 5th percentile means you're shorter than 95% of your peer group.
The NHS uses the UK90 growth reference charts, which are based on actual measurements of UK children and young people. These charts show expected growth patterns for different ages and sexes. For adults, height is typically less variable, but percentile rankings still provide useful context for understanding where you sit in the population distribution.
- 50th percentile = median (typical) height for your age and sex
- Above 95th percentile = taller than most peers
- Below 5th percentile = shorter than most peers
- Percentiles help GPs and health visitors identify unusual growth patterns
When a child's height falls consistently above or below expected percentile ranges, or crosses percentile lines significantly, this can warrant further investigation by a GP or paediatrician — though most children within the 5th–95th range are developing normally.
Clinically BackedWeight Loss
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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.
Using a Height Percentile Calculator and NHS Resources
A height percentile calculator takes your age, sex, and height measurement and compares it to NHS growth chart data to show where you sit percentile-wise. This is especially useful for parents tracking their child's development — percentile tracking is a routine part of NHS health visiting and school nurse checks.
For children, percentiles should be tracked consistently over time rather than interpreted as a single snapshot. A child on the 20th percentile who remains on the 20th percentile over multiple measurements is developing normally; a child who suddenly drops from the 50th to the 10th percentile may need review by a GP.
If you have concerns about your or your child's height or growth rate, always speak to your GP or health visitor. They can assess growth in context with family history, nutritional status, and overall health. Combined with our free BMI calculator, you can build a fuller picture of whether your weight and height sit in healthy ranges for your age and sex.
- 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 does it mean if my child is on the 10th percentile for height?
The 10th percentile means your child is shorter than 90% of children the same age and sex, but taller than 10%. This is within the normal range (5th–95th percentile). As long as your child is growing at a steady rate and is otherwise healthy, this is not a concern. Your health visitor will track percentile consistently over time.
Are UK height percentiles different from other countries?
Yes. The NHS uses the UK90 growth reference charts, which are based on UK children's actual measurements. Other countries may use different reference data. When moving to the UK or using international health services, ask which growth charts are being used — this ensures accurate comparison.
At what age do height percentiles become less useful?
Growth charts are most valuable during childhood and adolescence (ages 0–18). By early adulthood, height becomes relatively stable and percentiles are less relevant. Adults can use BMI calculators and weight converters to assess health context instead.
Should I worry if my child drops percentile lines?
Occasional small shifts are normal. However, if your child drops more than one percentile line (e.g., from 50th to 25th), or if growth slows significantly, discuss this with your GP or health visitor. They can assess whether this reflects normal variation or warrants investigation.
How does height percentile relate to BMI and healthy weight?
Height percentile and BMI are separate measurements. Two children on the same height percentile may have different BMIs depending on their weight. Our free BMI calculator and weight converter help you assess whether your weight is healthy for your height, age, and sex — ask your GP for personalised guidance.
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.