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
Free Health Calculators for UK Adults
Health calculators are quick, easy tools that help you understand your weight and overall health status in minutes. In the UK, most people use stone and pounds for body weight, which is why having access to accurate calculators that work with both metric and imperial measurements is so useful. Whether you're checking your BMI, converting between units, or planning weight management, our free calculators provide gradual improvement aligned with NHS guidance and UK health thresholds.
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.
What UK Health Calculators Can Help You With
The most commonly used health calculators in the UK measure BMI (Body Mass Index), which helps assess whether your weight falls within a healthy range according to NHS guidelines. A healthy BMI for most adults is between 18.5 and 24.9, though lower thresholds apply for people of South Asian, Chinese, Black African, or Black Caribbean heritage.
- BMI calculator: Enter your height and weight to get your BMI instantly and see which category you fall into
- Weight converter: Convert between kg, stone, and pounds — essential for UK health information where mixed units are common
- GLP-1 weight loss calculator: If you're considering weight management medication, this tool estimates potential weight loss based on clinical trial data
- Progress tracker: Log your weight regularly to monitor trends and stay motivated throughout your weight management journey
Each calculator is designed to work with UK measurements and is based on current NHS guidance for healthy weight ranges.
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.
How to Use These Tools Effectively
Start by using our free BMI calculator to establish your baseline health status — this takes less than a minute. Enter your height in centimetres and your weight in either kg or stone, and you'll instantly see your BMI and what it means for your health according to NHS thresholds.
If you want to understand your weight in different units, use the weight converter to switch between metric and imperial — useful if you're reading NHS health advice (which uses kg) but prefer thinking in stone and pounds.
For weight management planning, try our GLP-1 weight loss calculator to see projected outcomes based on clinical evidence. Always discuss results with your GP, especially if you're considering prescription weight management options.
- 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 healthiest BMI range in the UK?
According to NHS guidelines, a healthy BMI for most adults is 18.5 to 24.9. However, if you're of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends lower thresholds of 18.5 to 22.9 due to higher health risks at standard BMI levels. Your GP can advise on what's healthy for your individual circumstances.
Why do I need both kg and stone weight converters in the UK?
The NHS uses kilograms for clinical measurements, but most UK adults think and talk about weight in stone and pounds. Having a weight converter means you can easily switch between units when reading health advice, comparing weights, or tracking progress—whichever system feels most natural to you.
Can health calculators replace advice from my GP?
Health calculators are informational tools that help you understand your numbers, but they cannot replace professional medical advice. Always discuss your BMI, weight, or health concerns with your GP, especially if you're considering weight management medication or significant lifestyle changes.
Are these calculators accurate for children?
No—these adult calculators use adult BMI categories, which don't apply to children. Children's BMI is assessed using age and sex-specific growth charts. If you're concerned about your child's weight, ask your GP or health visitor for advice using the NHS Healthy Weight Calculator for children.
How often should I use a weight tracker or progress calculator?
Most UK health guidance suggests weighing yourself once a week on the same day, in the same clothes, at the same time of day for consistency. Our free progress tracker helps you log weekly measurements and spot trends over time—weight naturally fluctuates day-to-day, so weekly tracking is more meaningful than daily checks.
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.