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 Weight Should I Be? Find Your Healthy Weight Range
Your ideal weight depends on your height, age, and body composition — not a single "clinically supported number". The NHS uses BMI (body mass index) as the primary screening tool to determine whether you're at a healthy weight for your height. Use our free BMI calculator above to find your personal healthy weight range instantly. Most UK adults should aim for a BMI between 18.5 and 24.9, though ethnicity-specific thresholds apply for some groups. This guide explains what your ideal weight should be and how to use the calculator to find yours.
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.
How the BMI Calculator Helps You Find Your Healthy Weight
The BMI calculator on this page tells you instantly whether your current weight falls into a healthy range for your height. Here's how to interpret your result:
- BMI under 18.5 = Underweight (may need nutritional support)
- BMI 18.5–24.9 = Healthy weight range (NHS target)
- BMI 25.0–29.9 = Overweight (increased health risk)
- BMI 30.0+ = Obese (significant health risk)
If you're of South Asian, Chinese, Black African, or Black Caribbean heritage, lower thresholds apply — your healthy range is BMI 18.5–22.9. Enter your height and weight above to calculate your personal BMI and see exactly where you fall. Remember: BMI is a screening tool, not a diagnosis. It doesn't account for muscle mass, so athletes may have a higher BMI but still be very healthy.
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.
What to Do If You're Above a Healthy Weight
If your BMI calculator result shows you're overweight, the good news is that even small changes can improve your health. The NHS recommends losing weight at a rate of 0.5–1 kg per week for sustainable results. Start with simple steps: reduce portion sizes, increase daily activity, and aim for a modest calorie deficit of around 500 kcal per day.
For those with a BMI over 30 or between 27–29.9 with weight-related health conditions (high blood pressure, type 2 diabetes, or sleep apnoea), prescription weight loss support may be available through the NHS or your GP. Track your progress using our free progress tracker to stay motivated. Always speak to your GP before starting any significant weight loss programme, especially if you have existing health conditions.
- 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's the difference between healthy weight and ideal weight?
Healthy weight is a BMI range (18.5–24.9) aligned with NHS guidelines. Ideal weight is individual — it depends on your muscle mass, bone density, and personal health goals. Two people at the same height may have different healthy weights. Your GP can discuss what's realistic and healthy for you.
Does my age affect what weight I should be?
BMI categories are the same for all adults aged 18+, regardless of age. However, older adults naturally lose muscle mass, so maintaining some weight is important for strength and bone health. Discuss age-specific health targets with your GP rather than aiming for a lower weight.
Is BMI accurate for muscular people?
No. BMI doesn't distinguish between muscle and fat. Athletes or very muscular individuals may have a high BMI but low body fat. If you're very active, discuss your healthy weight range with your GP or a healthcare professional rather than relying on BMI alone.
How do I calculate my healthy weight range for my height?
Use our BMI calculator above — it shows your personal range instantly. Alternatively, multiply your height in metres squared by 18.5 (lower healthy limit) and 24.9 (upper limit). For example, at 1.75m: 18.5 × (1.75)² = 56.6 kg lower; 24.9 × (1.75)² = 76.2 kg upper.
Can I use a weight converter to check my healthy weight in stone?
Yes. Use our free weight converter to switch between kilograms and stone. For example, a healthy weight range of 56–76 kg converts to approximately 8st 12lbs to 11st 13lbs. Most UK adults find it easier to track their weight in stone and pounds.
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.