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's the Perfect Weight For My Height?
There's no single "perfect" weight — what matters is whether your weight is healthy for your individual height, age, and body composition. The NHS uses BMI (body mass index) as a screening tool to determine healthy weight ranges. For most UK adults, a healthy BMI falls between 18.5 and 24.9, though ethnicity-specific thresholds apply. Your GP can provide personalised advice about what a healthy weight means for you specifically, taking into account your overall health, fitness level, and any existing health conditions.
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 healthy weight range for any given height is calculated using BMI thresholds. For example, at 5ft 8in (173cm), a healthy weight typically falls between approximately 55kg (8st 10lbs) and 75kg (11st 11lbs). However, this varies significantly by individual height. Use our free BMI calculator above to enter your own height and instantly see your personal healthy weight range — the calculator displays results in both stone and kilograms for UK health guidance.
- South Asian, Chinese, Black African, or Black Caribbean adults: The NHS recommends slightly lower thresholds due to higher health risks at lower BMI levels. Your healthy BMI range may start at 18.5 and end at 22.9 rather than 24.9.
- Individual variation: Muscle mass, bone density, and frame size mean two people at the same height and weight can have very different body compositions.
- Waist circumference also matters: Where you carry weight is important. Men should aim for a waist under 94cm; women under 80cm (increased risk thresholds).
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.
Why "Perfect Weight" Is Individual
Rather than aiming for a single "perfect" number, focus on reaching a healthy weight range for your height that feels sustainable and supports your overall wellbeing. This means a weight at which you have good energy levels, can stay physically active, and feel confident. The weight converter on this page helps you understand your current weight in both metric and imperial units, while the BMI calculator provides NHS-aligned guidance on whether your weight falls within a healthy range. If you're significantly above or below the healthy range, your GP can discuss personalised strategies — which might include dietary changes, increased physical activity, or in some cases, prescription weight management support if clinically appropriate.
- 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 who is 5ft 10in tall?
For a 5ft 10in (178cm) adult, the NHS healthy weight range is approximately 64kg to 86kg (10st 1lb to 13st 8lbs) for a BMI between 18.5 and 24.9. Use our free BMI calculator to see your exact range based on your height — results display in both stone and kilograms for UK measurements.
Does perfect weight change with age?
Healthy BMI ranges remain consistent across adulthood, but body composition naturally changes with age. Older adults may have reduced muscle mass, making it important to maintain strength through activity. Your GP can advise on healthy weight goals specific to your age and circumstances.
What if I'm muscular — will my BMI be high even at a healthy weight?
Yes. BMI doesn't distinguish between muscle and fat. If you're very athletic or muscular, you may have a higher BMI while being perfectly healthy. Waist circumference and body composition are better measures. Your GP can assess your individual health risk.
How do I know if my current weight is healthy for me?
Calculate your BMI using our free tool on this page — it instantly shows whether your weight falls in the healthy range for your height. However, BMI is a screening tool only. Your GP can provide a full health assessment considering your medical history, fitness level, and any health conditions.
Can prescription weight loss medication help me reach a healthy weight?
If you have a BMI of 30 or above (or 27+ with weight-related health conditions), your GP may refer you to specialist weight management services. Some adults are prescribed weight loss medication like Mounjaro or Wegovy alongside diet and exercise — but these require clinical assessment and a prescription.
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.