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
Is 81.5kg a Healthy Weight in Stone and Pounds?
81.5kg converts to approximately 12 stone 11.2 pounds (or 12 stone and 11 lbs). Whether this weight is healthy depends entirely on your height. For a shorter adult, 81.5kg may fall into the overweight range; for a taller adult, it could be healthy. Use our free BMI calculator above to check your personal BMI instantly based on your exact height, and discover whether 81.5kg is healthy for you specifically.
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.
Healthy Weight Ranges by Height at 81.5kg
At 81.5kg, your weight status depends on your height. Use this table to see whether you fall into a healthy range according to NHS guidelines:
- 5ft 2in (157cm): BMI 33.0 — Obese (Class I). Outside healthy range.
- 5ft 7in (170cm): BMI 28.2 — Overweight. Just outside healthy range (18.5–24.9).
- 5ft 11in (180cm): BMI 25.3 — Overweight (just above healthy, which ends at 24.9).
- 6ft 2in (188cm): BMI 23.1 — Healthy weight. Within the healthy BMI range.
The same weight creates very different health profiles depending on your height. For adults of South Asian, Chinese, Black African, or Black Caribbean heritage, the NHS recommends lower BMI thresholds, so your healthy weight range may be slightly lower.
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.
NHS Guidance: What to Do If You're Outside the Healthy Range
If 81.5kg puts you in the overweight or obese category based on your height, the NHS recommends a gradual approach. Aim to lose weight at a rate of 0.5 to 1 kg per week through a combination of reduced-calorie eating and increased physical activity. Even a 5% reduction in body weight can improve blood pressure, blood sugar, and cholesterol levels. Waist measurement also matters: men should aim for under 94cm (37in) and women under 80cm (31.5in). Speak to your GP about weight management options, including lifestyle support, structured programmes, or prescription weight loss medication if eligible. Track your progress with our free progress tracker to stay motivated.
- 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 81.5kg in stone and pounds exactly?
81.5kg converts to 12 stone and 11.2 pounds (often rounded to 12 stone 11 lbs). To convert kilograms to stone, divide the kilogram value by 6.35029. This straightforward conversion helps you understand your weight in traditional UK measurements.
How do I know if 81.5kg is a healthy weight for me?
Use our BMI calculator on this page with your exact height to get your personal BMI. A healthy BMI is 18.5–24.9 according to NHS guidelines. For South Asian or Black African heritage, the healthy range is 18.5–22.9. Your GP can also advise you based on your overall health.
What is a healthy weight range if I'm 5ft 8in tall at 81.5kg?
At 5ft 8in (173cm), 81.5kg gives a BMI of approximately 27.2, which falls in the overweight category. For healthy weight at your height, the NHS range is roughly 55–73kg (8st 9lbs to 11st 7lbs). Losing 8–10kg could bring you into the healthy range.
Can I use the weight converter on this page to check other weights?
Yes. Our free weight converter lets you convert between kilograms, stone, and pounds instantly. Try converting different weights to see what various BMI categories look like for your height. Combined with our BMI calculator, you can explore what a healthy weight range means for you personally.
What should I do if 81.5kg is outside my healthy range?
Start by speaking to your GP about sustainable weight loss options. The NHS recommends losing 0.5–1kg per week through balanced eating and activity. Your GP can refer you to tier 3 weight management services, or discuss whether prescription weight loss medication might be appropriate for you based on your health.
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.