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 Kilograms — NHS Weight Categories
A BMI chart in kilograms helps you understand where your weight falls according to NHS health guidelines. The standard BMI formula divides your weight in kg by your height in metres squared. Understanding your BMI range is a useful first step in assessing your health, though BMI has important limitations — it doesn't distinguish between muscle and fat, and may not be accurate for athletes or elderly individuals. Use our free BMI calculator above to find your personal BMI instantly, and this chart to see where you fit within NHS categories.
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 BMI Categories in Kilograms
The NHS recognises five main BMI categories that apply to UK adults:
- Underweight: BMI below 18.5 (weight too low for optimal health)
- Healthy weight: BMI 18.5 to 24.9 (recommended range)
- Overweight: BMI 25.0 to 29.9 (increased health risks)
- Obese (Class I): BMI 30.0 to 34.9
- Obese (Class II): BMI 35.0 to 39.9
- Severely obese (Class III): BMI 40.0 and above (significant health risks)
For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends lower thresholds — healthy weight is BMI 18.5 to 22.9, and overweight begins at 23.0 — because these groups face higher cardiovascular and diabetes risk at lower BMI levels. Your GP can explain what your personal healthy BMI range means for your health.
Clinically BackedWeight Loss
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.
NHS Weight Management Support and Next Steps
If your BMI falls outside the healthy range, the NHS offers a structured weight management pathway. Tier 1 includes self-help resources and community programmes; Tier 2 involves GP-led interventions and behaviour change support; Tier 3 is specialist multidisciplinary weight management services where prescription medications may be considered; and Tier 4 is bariatric surgery for severe obesity with health complications.
Your GP is the best starting point — they can assess your individual health, discuss weight loss goals, and recommend the appropriate tier of support. Even modest weight loss of 5–10% can improve blood pressure, blood sugar control, and reduce joint strain. Use our free weight converter to track your progress in both kg and stone.
- 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 BMI formula and how do I calculate it from my weight in kilograms?
BMI = weight (kg) ÷ height (m)². For example, if you weigh 75kg and are 1.73m tall, your BMI is 75 ÷ (1.73 × 1.73) = 25.1, which falls in the overweight range. Our free BMI calculator above does this instantly — just enter your weight and height.
What does NHS say is a healthy BMI?
The NHS defines a healthy BMI as 18.5 to 24.9 for most UK adults. For people of South Asian, Chinese, Black African, or Black Caribbean heritage, the healthy range is slightly lower: 18.5 to 22.9. These lower thresholds reflect higher health risks at standard BMI levels for these populations.
At what kilogram weight does BMI become overweight?
The BMI threshold for overweight starts at 25.0. The kilogram weight at which you reach this depends on your height. For someone 1.70m tall, overweight begins around 72kg; for someone 1.80m tall, it's around 81kg. Use our free weight converter and BMI calculator to find your exact threshold.
Why does NHS use different BMI categories for some ethnic groups?
Research shows that people of South Asian, Chinese, Black African, and Black Caribbean heritage have higher risk of type 2 diabetes and heart disease at lower BMI levels compared to white European populations. The NHS adjusted guidelines to reflect this biological reality and ensure early identification of health risk.
What are the limitations of using a BMI chart?
BMI doesn't distinguish muscle from fat — athletes may have high BMI but low body fat. It also ignores where fat is stored (waist circumference matters), doesn't account for age-related muscle loss, and may be inaccurate during pregnancy. Your GP can assess your individual health beyond BMI alone.
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.