Calorie Deficit/Surplus Calculator

Calculate the exact calorie deficit or surplus needed to reach your weight goals. Get personalized recommendations for safe and sustainable weight management.

Plan Your Weight Goal

Current Weight (kg)

Target Weight (kg)

Timeframe (weeks)

Current Daily Calories (Maintenance)

Don't know? Calculate your TDEE

Activity Level Change

Enter your details to calculate your calorie plan

Need help planning your nutrition?

Calculate Macros Find Maintenance Calories

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Macros Calculator

Plan your protein, carbs, and fat intake

Exercise Calories

Calculate calories burned during workouts

Frequently Asked Questions

How long will it take to lose/gain my target weight?

The timeline depends on your deficit/surplus size and individual factors. A 500-calorie daily deficit typically results in 1 pound of weight loss per week, but expect slower progress as you get closer to your goal due to metabolic adaptation. Use our calculator to get personalized timelines.

What if the scale isn't moving despite being in a calorie deficit?

Weight loss plateaus are normal due to water retention, hormonal fluctuations, and metabolic adaptation. If the scale hasn't moved for 2-3 weeks, try reducing your calorie target by 100-200 calories, increasing activity, or taking a diet break for 1-2 weeks at maintenance calories.

Is it safe to have a large calorie deficit for faster weight loss?

Large deficits (>1000 calories) can lead to muscle loss, nutrient deficiencies, metabolic slowdown, and are hard to sustain. Stick to moderate deficits (500-750 calories) for sustainable fat loss while preserving muscle mass. Consult a healthcare provider before attempting aggressive deficits.

Do I need to eat back calories burned from exercise?

If your TDEE calculation includes your exercise, don't eat back exercise calories. If you used a sedentary TDEE and track exercise separately, consider eating back 50-75% of exercise calories, as fitness trackers often overestimate calorie burn.

Should I have different calorie targets on rest days vs training days?

You can use the same daily calorie target for simplicity, or adjust based on activity (higher on training days, lower on rest days). Some people prefer carb cycling - more carbs on training days, more fats on rest days, while keeping calories and protein consistent.

What's the minimum calorie intake I should never go below?

Generally, women shouldn't go below 1200 calories and men shouldn't go below 1500 calories without medical supervision. Very low-calorie diets can lead to nutrient deficiencies, muscle loss, and metabolic damage. Aim for moderate, sustainable deficits instead.

📚 Scientific References & Resources

1. Quantification of the effect of energy imbalance on bodyweight (2011)

The Lancet - Foundational mathematical model challenging the simplified 3500-calorie rule.

2. Persistent metabolic adaptation 6 years after 'The Biggest Loser' (2016)

Obesity - Research showing the long-term metabolic consequences and slowdown following rapid weight loss.

3. NHLBI Clinical Guidelines on the Identification, Evaluation, and Treatment of Overweight and Obesity in Adults (2013)

Evidence-based recommendations for safe weight loss rates and methods from the National Heart, Lung, and Blood Institute.

4. Metabolic Adaptation in Long-term Weight Management: Updated Meta-Analysis (2024)

Obesity Reviews - The latest scientific findings on how metabolism adapts and slows down during a weight loss phase.