Calorie Deficit Calculator
Calculate the daily calorie deficit needed to reach your target weight. See safe vs aggressive rates and timeline projections.
For informational purposes only. Not a substitute for professional medical advice. Consult a healthcare provider before making changes to your diet or exercise routine.
About Calorie Deficit Calculator
Losing weight in a healthy, sustainable way starts with understanding the numbers. This calculator takes your current weight, target weight, timeframe, and TDEE to determine exactly what daily calorie deficit you need.
How the Calculation Works
The calculator uses the standard estimate that 1 kg of body fat contains approximately 7,700 calories. It divides the total calories you need to burn by the number of days in your timeframe to find your required daily deficit. Your daily calorie intake is then your TDEE minus this deficit.
Safe vs Aggressive Deficits
A moderate deficit of around 500 calories per day leads to about 0.5 kg (1 lb) of weight loss per week. The calculator flags deficits over 1,000 calories per day as potentially risky and warns if your daily intake would fall below 1,200 calories. These guardrails help you plan a realistic approach. If you need to find your TDEE first, use the TDEE calculator.
Timeline Projection
The week-by-week projection shows your expected weight at each milestone, helping you visualise your progress. Keep in mind that real-world weight loss is rarely perfectly linear. To pair your deficit with a proper nutrition plan, the macro calculator can help you balance protein, carbs, and fat within your calorie target.
Privacy
All calculations run entirely in your browser. No personal data is sent to any server.
Frequently Asked Questions
What is a calorie deficit?
A calorie deficit occurs when you consume fewer calories than your body burns in a day. This forces your body to use stored energy (primarily fat) to make up the difference, resulting in weight loss over time. One pound of body fat contains roughly 3,500 calories.
What is a safe daily calorie deficit?
Most health professionals recommend a deficit of 500 to 750 calories per day, which translates to about 0.5 to 0.75 kg (1 to 1.5 lbs) of weight loss per week. Deficits over 1,000 calories per day are generally considered too aggressive for most people and can lead to muscle loss and nutrient deficiencies.
What TDEE value should I enter?
TDEE is your Total Daily Energy Expenditure, which represents the total calories you burn each day including activity. If you do not know yours, use our TDEE calculator first. A typical TDEE ranges from about 1,800 to 3,000 calories depending on your size, age, gender, and activity level.
Why does the calculator warn about very low calorie intake?
Eating below 1,200 calories per day is generally not recommended without medical supervision. Very low calorie diets can cause nutrient deficiencies, muscle loss, metabolic slowdown, and other health issues. If your calculated intake falls below this level, consider extending your timeframe or increasing your TDEE through exercise.
How accurate is the weight loss timeline?
The timeline provides a linear estimate based on consistent daily deficit. In reality, weight loss is not linear. You may lose more in the first few weeks due to water weight, then progress may slow. Metabolic adaptation, changes in activity, and other factors all affect actual results.