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
BMI Chart in Kg — What Your Weight Means
A BMI chart in kg shows you where your weight sits in NHS health categories. Whether you're checking your own health or understanding weight thresholds, this guide explains the BMI formula, the standard ranges used across the UK, and why BMI matters alongside other health measures. Use our free BMI calculator above to find your personal BMI instantly, or read on to understand the charts and categories that apply to you.
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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.
Understanding the NHS BMI Categories in Kilograms
The BMI formula is straightforward: divide your weight in kilograms by your height in metres squared (BMI = kg ÷ m²). The NHS uses standard BMI range categories to classify adults:
- Below 18.5 kg/m²: Underweight
- 18.5–24.9 kg/m²: Healthy weight
- 25.0–29.9 kg/m²: Overweight
- 30.0–34.9 kg/m²: Obese (Class I)
- 35.0–39.9 kg/m²: Obese (Class II)
- 40.0+ kg/m²: Severely obese (Class III)
For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, the healthy BMI threshold is lower—18.5 to 22.9 kg/m²—because these groups face higher health risks at lower weights. Your GP can explain which thresholds apply to you personally.
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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.
BMI Limitations and What Else to Consider
While a BMI calculator is useful, the chart has important limits. BMI does not distinguish muscle from fat—athletes may have a high BMI but low body fat. It also ignores where fat is stored; waist circumference matters too. NHS BMI guidelines recommend checking your waist measurement alongside BMI: men should aim for under 94cm, women under 80cm. For the full picture of your health, discuss your weight, BMI, and waist measurement with your GP, especially if you have weight-related health conditions like type 2 diabetes or high blood pressure.
- 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 BMI in kg means I'm at a healthy weight?
According to NHS guidelines, a healthy BMI is 18.5 to 24.9 kg/m². For South Asian, Chinese, Black African, or Black Caribbean adults, the healthy range is 18.5 to 22.9 kg/m². Use our free BMI calculator above to check where you sit, or ask your GP for personalised advice.
How do I calculate my BMI from my weight in kg?
Divide your weight in kilograms by your height in metres squared. For example, if you weigh 70kg and are 1.73m tall: 70 ÷ (1.73 × 1.73) = 23.4 BMI. Our weight converter and BMI calculator on this page can do this instantly for you.
Is a BMI of 30 kg/m² considered obese according to the NHS?
Yes, the NHS classifies a BMI of 30.0–34.9 kg/m² as Class I obesity. However, BMI is just one health measure—your GP will assess your overall health, including waist circumference, blood pressure, and any weight-related conditions, before making recommendations.
Do the BMI categories in kg apply to children?
No. Children use age and sex-specific centile charts, not adult BMI categories. If you're checking a child's weight, speak to your health visitor or GP, or use the NHS Healthy Weight Calculator designed for children.
What's the difference between BMI in kg and BMI in pounds?
The result is identical—BMI is the same whether you calculate it in kilograms or pounds. The formula just changes slightly. We recommend using kg for accuracy since the NHS uses metric measurements, and our weight converter can help you switch between units easily.
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.