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Use this weight loss calculator for a clear health & fitness estimate. Results update instantly in your browser.
What this calculator does
Estimate a calorie deficit and timeline for a chosen weight-loss goal.
How to use this calculator
- Enter current weight, target, timeframe, and activity assumptions.
- Review the calculation assumptions before using the result.
- Use a sustainable pace rather than an extreme deficit.
How to calculate
Choose the calculation mode where available, then enter the values requested by the weight loss calculator. Results update immediately.
Worked example
The defaults provide a complete worked example. Change any value to recalculate the result and any schedule shown.
Understanding your result
Use a sustainable pace rather than an extreme deficit.
- Talk to a clinician before major changes.
- Double-check values and units before calculating.
This calculator provides an educational estimate and is not medical advice or a diagnosis.
Frequently asked questions
What does this weight loss calculator do?
Estimate a calorie deficit and timeline for a chosen weight-loss goal.
How do I use this weight loss calculator?
Enter current weight, target, timeframe, and activity assumptions.
What does the result mean?
Use a sustainable pace rather than an extreme deficit.
What should I check before relying on it?
Talk to a clinician before major changes.