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 the Optimal Weight For Your Height?
There is no single "optimal" weight that applies to everyone at a given height — weight depends on age, muscle mass, bone density, and individual health. However, the NHS provides evidence-based healthy weight ranges based on BMI (Body Mass Index), which gives you a target zone rather than a single number. Your optimal weight is the range within a BMI of 18.5 to 24.9 for most UK adults. For some ethnic groups, including those of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends slightly lower thresholds. Your GP can help you determine what's realistic and healthy for your individual circumstances.
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 Healthy Weight Ranges By Height
The NHS uses BMI to define healthy weight ranges. To find your optimal weight for your height, calculate the range between a BMI of 18.5 and 24.9. For example, an adult who is 5ft 8in (173cm) tall has a healthy weight range of approximately 55.4 kg to 74.5 kg (8st 10lbs to 11st 10lbs). Someone 5ft 4in (163cm) tall should aim for roughly 49 kg to 66 kg (7st 10lbs to 10st 6lbs).
These ranges account for natural variation in body composition. Two people at the same height and weight can look and feel different because muscle weighs more than fat. Use our free BMI calculator above to find your personal healthy weight range instantly — simply enter your height and current weight to see where you fall on the NHS scale. For precise targets, your GP or a registered dietitian can assess your individual circumstances, including medical history and fitness level.
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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.
Why Optimal Weight Varies Between Individuals
Optimal weight is personal and influenced by several factors beyond height. Age, gender, muscle mass, bone density, genetics, and any underlying health conditions all play a role. Athletes often have a higher BMI but lower body fat because muscle is denser than fat. Older adults may have naturally lower muscle mass. Pregnant women need additional weight gain for health.
Rather than chasing a single number, focus on health markers: blood pressure, blood sugar levels, cholesterol, energy levels, and how you feel physically. The NHS recommends alongside BMI assessment, checking your waist circumference — over 94cm (37in) for men or 80cm (31.5in) for women suggests increased health risk, regardless of BMI. Our weight converter tool helps you switch between kg, stone, and pounds to compare your weight against NHS guidance in whichever units feel most natural to you.
- 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 healthy weight range for someone 5ft 10in tall?
At 5ft 10in (178cm), a healthy BMI range of 18.5–24.9 gives a weight range of approximately 59–79 kg (9st 4lbs to 12st 6lbs). Use our free BMI calculator to enter your exact height and see your personalised range instantly.
Is optimal weight the same as ideal weight?
Not exactly. Ideal weight is often calculated using formulae like the Devine formula, which gives a single target. Optimal weight is a range that accounts for individual variation in muscle, bone, and body composition. NHS healthy weight ranges are more practical and realistic for most people.
How do I know if I'm within an optimal weight for my height?
Calculate your BMI using your height and weight. A BMI between 18.5 and 24.9 is healthy for most UK adults. For South Asian, Chinese, Black African, or Black Caribbean adults, 18.5 to 22.9 is recommended. Our BMI calculator above gives gradual improvement with your personalised healthy range.
Does optimal weight change with age?
BMI categories remain the same across age groups, but optimal weight in practice may shift slightly due to natural muscle loss with age, changes in metabolism, and varying activity levels. Your GP can advise whether your current weight is optimal for your specific age and health status.
What if my weight is outside the healthy range?
If your weight falls outside the healthy BMI range, sustainable lifestyle changes (diet and exercise) supporting 0.5–1 kg weight loss per week are recommended by the NHS. In some cases, your GP may discuss weight management support or specialist services. Track progress with our free progress tracker tool.
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.