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 Is 18 Foot in Centimetres?
18 feet converts to 548.64 centimetres. This is approximately 5 metres and 49 centimetres. In the UK, we typically express heights under 7 feet in feet and inches rather than as a single foot value, so 18 feet is an unusually tall measurement — well above average adult height. For context, the average UK adult male height is around 175 cm (5ft 9in), making an 18-foot height roughly 3 times taller than average. If you're working with height measurements for health assessments or BMI calculations, use our free BMI calculator and weight converter above to get accurate health context for your measurements.
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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.
Height Conversion Reference for UK Health Measurements
How to convert 18 foot to centimetres: Multiply the number of feet by 30.48 (the exact conversion factor). 18 × 30.48 = 548.64 cm.
In UK health contexts, heights are usually recorded in feet and inches combined rather than as total feet. For example, an adult might be 5ft 10in (178 cm) rather than described as a single "foot" value.
- 18 foot = 548.64 cm
- 18 foot = 5.49 metres
- 18 foot ≈ 18 storeys tall (each storey averages 3–4 metres)
For health and BMI assessments, heights are almost always under 7 feet (213 cm), so an 18-foot measurement is outside the range of typical human height calculations. If you're measuring a person's height for health purposes, heights are expressed in feet and inches — for instance, 5ft 8in (173 cm) — rather than as a single foot figure.
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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 Height in Health Assessments and NHS Guidance
For NHS health assessments, weight management, and BMI calculations, height is a critical measurement. The NHS uses height in metres (or feet and inches in the UK) combined with weight in kilograms or stone to calculate BMI.
If you're calculating your BMI or exploring weight management with guidance like the NHS Health Check, you'll need your height in feet and inches — for example, 5ft 7in (170 cm) — not as a total foot measurement. Use our free weight converter and BMI calculator above to check your personal BMI and get NHS-aligned health context. For adults exploring weight loss options including prescription medications like Mounjaro or Wegovy, accurate height measurement is essential for determining eligibility and safe dosing.
- 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 18 foot to centimetres?
Multiply 18 by the conversion factor 30.48. So 18 × 30.48 = 548.64 cm. This is an extremely tall measurement — well outside the range of typical human heights used in health assessments.
Is 18 foot a realistic human height?
No. 18 feet (548.64 cm or 5.49 metres) is far beyond any recorded human height. The tallest person ever documented was Robert Wadlow at 8ft 11in (272 cm). For health purposes, typical adult heights range from 5ft (152 cm) to 6ft 6in (198 cm).
What is the average UK adult height in centimetres?
The average UK adult male height is approximately 175 cm (5ft 9in), and the average UK adult female height is approximately 162 cm (5ft 4in). These measurements are used alongside weight to calculate BMI for health assessments.
How do I use my height to calculate BMI?
Use your height in metres squared (m²) and divide your weight in kilograms by this figure. For example, at 175 cm (1.75 m), BMI = weight (kg) ÷ (1.75)². Try our free BMI calculator above for gradual improvement.
Why does the NHS need my exact height for health assessments?
Height is essential for calculating BMI, which is used to assess health risk and determine eligibility for weight management support. Accurate height ensures your BMI category (healthy weight, overweight, obese) is correct, helping your GP give you the right 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.