Setting a goal you can actually reach is the hardest part of losing weight. Our free 6-week weight loss calculator turns your current weight into a realistic six-week target, so you know what to aim for before you start. It was built by the team at 3-1-5 Health Club in Lancaster and takes less than a minute.
Calculate Your 6-Week Goal
How the 6-week weight loss calculator works
Enter your current weight, gender and activity level, then choose a goal preference. Each preference is a percentage of your starting body weight to lose over six weeks:
- Conservative (3%): a gentle start that is easy to sustain.
- Moderate (4%): a balance of progress and sustainability.
- Aggressive (5%): ambitious, and best done with support.
You will see your target weight, your total loss goal and a weekly average. For example, someone starting at 80kg who chooses the moderate goal would aim to lose about 3.2kg, giving a target of 76.8kg after six weeks.
What is a realistic rate of weight loss?
NHS guidance is to aim for a gradual loss of around 0.5kg to 1kg (1lb to 2lb) a week. Losing weight faster than that is harder to maintain and is not recommended without medical advice. For most people the conservative and moderate goals sit comfortably inside that range. If you weigh more than about 120kg, the aggressive 5% goal works out at over 1kg a week, so you may prefer a lower setting.
How to reach your six-week goal
A calculator gives you the destination. These habits help you get there:
- Train with a plan. Combine strength training with cardio. Our gym has a free weights area, cable machines and cardio equipment.
- Find something you enjoy. Choose from our fitness classes, check the timetable, or swim in one of our three swimming pools.
- Get expert support. Our personal training includes the X-Force 1:1 programme, a six-week plan of two 30-minute sessions a week with simple nutrition guidance.
- Eat consistently. Small, repeatable changes to what you eat and drink beat crash diets.
- Protect your sleep and recovery. Rest, hydration and stress all affect progress.
Track more than the scales
Weight is only one measure. A Seca body composition scan shows fat mass, muscle mass and water content, so you can see real change even when the scales move slowly.
Weight loss calculator FAQs
Is the weight loss calculator free?
Yes. It is free to use and you do not need to be a member of 3-1-5.
How accurate is the forecast?
It is a guide, not a guarantee. Real results depend on your food, activity, sleep, health and consistency.
Why does the calculator ask for my name and email?
The calculator asks for your name and email before it shows your forecast. These details are handled in line with our privacy policy.
Can I use the calculator if I have a health condition?
Speak to your GP before starting a new exercise or weight loss programme, especially if you have a medical condition, are pregnant or take regular medication. Weight targets for children and teenagers should be set by a healthcare professional.
Ready to start your six weeks?
See our current offers, explore personal training, or contact the team to arrange a visit to 3-1-5 Health Club in Lancaster.
This calculator provides general guidance only and is not medical advice.