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
12 Week Weight Loss Tracker — Your Guide to Sustainable Progress
A 12 week weight loss tracker is a simple tool to monitor your progress towards healthier weight management UK targets. Whether you're making lifestyle changes, starting prescription weight loss medication, or following an NHS weight loss programme, tracking your weight over 12 weeks helps you stay motivated and identify patterns in your weight loss journey. This guide explains how to use a tracker effectively, what to measure beyond the scales, and how to set realistic goals for sustainable results.
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 to Use a 12 Week Weight Loss Tracker Effectively
A blank 12 week weight loss tracker works best when you measure consistently and track multiple metrics, not just weight alone.
- Weekly weigh-ins: Weigh yourself at the same time each week (ideally morning, before food) for accurate comparisons. Weight naturally fluctuates by 1–2 kg due to water retention, hormones, and digestion.
- Measurements: Record waist, hip, and chest circumference monthly — you may lose inches even if the scales don't move, as muscle weighs more than fat.
- BMI tracking: Use our free BMI calculator on this page to log your BMI weekly. This gives health context beyond raw weight and aligns with NHS weight loss targets.
- Progress photos: Take monthly photos from the same angles — visual changes are often more motivating than numbers.
- Energy and mood: Note how you feel, sleep quality, and activity levels. These often improve before significant weight loss occurs.
The NHS recommends losing 0.5–1 kg per week for sustainable results. Over 12 weeks, realistic weight loss ranges from 6–12 kg depending on your starting point, diet, and activity level.
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.
What to Track Beyond Weight
Effective weight loss tracking includes health markers beyond the number on the scales. Blood pressure, resting heart rate, energy levels, and how your clothes fit all indicate progress.
If you're using prescription weight loss medication (such as GLP-1 weight loss injections), your tracker should include appetite changes, side effects, and dose adjustments. Our GLP-1 weight loss calculator can help you project realistic outcomes at different doses over your 12 week period.
Use your tracker to note which eating patterns, activities, and circumstances support your progress. This self-awareness is crucial for sustainable weight management UK. Many people find tracking dietary intake (calories or meals) helpful alongside weight tracking, though this is optional — focus on what works for 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 should a blank 12 week weight loss tracker include?
A basic tracker includes: weekly weigh-in date and weight in kg, BMI (use our free calculator above), waist measurement, notes on diet and activity, energy levels, and any medications or side effects. Keep it simple — you're more likely to use it consistently if it's not overcomplicated.
How often should I weigh myself when tracking weight loss?
Once per week at the same time is ideal — typically early morning before food. Daily weighing can be discouraging due to normal water retention and hormonal fluctuations. Weekly tracking gives you a clearer picture of your actual progress over the 12 week period.
Is 12 weeks enough time to see significant weight loss?
Yes. Over 12 weeks at a sustainable rate of 0.5–1 kg per week, you could expect to lose 6–12 kg. This is significant health progress. Clinical trials show that most weight loss medication effects are visible within 8–12 weeks, making this timeframe realistic for tracking bmi weight loss improvements.
What if my weight fluctuates or stays the same for a week?
Weight fluctuations are completely normal due to water retention, hormones, and digestion timing. If your weight hasn't changed for 2–3 weeks despite effort, review your calorie intake, activity level, and stress. If on prescription weight loss medication, your GP may adjust your dose after 4 weeks.
Can I use a tracker if I'm on prescription weight loss medication?
Absolutely. Tracking is especially valuable with weight loss injections. Note your dose, any side effects, appetite changes, and weekly weight. This information helps your prescriber assess whether your dose is effective and supports lose weight UK goals safely and effectively.
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.