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
Height From BMI — What You Need to Know
You cannot calculate height directly from BMI alone — BMI requires both weight and height as inputs. However, you can work backwards: if you know your weight and BMI, you can estimate height; or if you know your height and BMI, you can find your target weight range. The NHS BMI formula uses both measurements together to assess whether a weight is healthy for a specific height. Understanding this relationship helps you use the BMI range UK guidelines effectively and find your healthy weight range for your individual height.
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 BMI Uses Height and Weight Together
The BMI formula is: weight (kg) ÷ height (metres) squared. This means BMI always depends on both measurements — you cannot determine one from the other alone. However, you can rearrange the formula to find what you're looking for:
- To find healthy weight range: Multiply your height (m²) by 18.5 and 24.9 to get the lower and upper healthy weight bounds for your height.
- To estimate height from weight and BMI: Divide weight (kg) by your BMI, then take the square root.
- Example: If you weigh 70kg and have a BMI of 25, your height would be approximately 1.67 metres (5ft 6in).
Use our free BMI calculator above to check your personal BMI instantly — it handles all the calculations for you across different heights and weights.
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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 Height Matters More Than You Think
Two people with the same weight can have completely different BMIs depending on their height. A 70kg person who is 1.60m tall has a BMI of 27.3 (overweight), while a 70kg person who is 1.80m tall has a BMI of 21.6 (healthy weight). This is why healthy BMI ranges are always height-specific. The NHS BMI guidance recognises this by providing BMI categories (healthy weight, overweight, obese) rather than fixed weight targets. For South Asian, Chinese, Black African, and Black Caribbean adults, the NHS recommends lower thresholds because health risks increase at lower BMI levels for these groups.
Use our weight converter to check your weight in stone, pounds, or kilograms, then calculate your actual BMI based on your true height.
- 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.
Can I work out my height if I only know my BMI?
No — BMI alone doesn't tell you height. You need either weight and BMI (to estimate height), or height and BMI (to find your healthy weight range). BMI is calculated from both measurements together, so neither can be determined from BMI alone.
What's the healthy BMI range for my height?
Healthy BMI is 18.5–24.9 for most UK adults. For South Asian, Chinese, Black African, or Black Caribbean adults, it's 18.5–22.9. To find your healthy weight range for your specific height, multiply your height in metres squared by 18.5 and 24.9. Your GP can also advise based on your individual health.
Why do two people of different heights have different healthy weights?
Because BMI accounts for how weight is distributed across height. A taller person can be a healthy weight at a higher absolute weight than a shorter person. This is why height-specific BMI ranges are essential for accurate health assessment.
How do I calculate my healthy weight range from my height?
Use the formula: height (m)² × 18.5 = lower healthy weight; height (m)² × 24.9 = upper healthy weight. For example, at 1.70m, healthy weight is 53.4–72kg (8st 6lbs–11st 5lbs). Try our BMI calculator for gradual improvement.
Does the overweight BMI threshold change depending on height?
No — the BMI threshold stays the same (25.0 is the start of overweight) regardless of height. However, the actual weight that reaches BMI 25 varies dramatically by height. That's why assessing health always requires knowing both weight and height together.
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.