Cutting Calorie Calculator
Calculate calorie deficit and macros for fat loss cutting phases while preserving muscle. Enter values for instant results with step-by-step formulas.
Formula
Cut Calories = TDEE - Deficit; Protein = Lean Mass x 1.1g/lb; Fat = Weight(kg) x 0.7g/kg; Carbs = Remaining / 4
BMR is calculated via Mifflin-St Jeor, multiplied by activity factor for TDEE. The deficit (300-750 kcal) is subtracted based on cut aggressiveness. Protein is elevated to 1.1g/lb lean mass for muscle preservation. Fat is set at 0.7g/kg for hormonal health. Carbohydrates fill remaining calories. A floor of 1,500 kcal (male) or 1,200 kcal (female) is enforced.
Worked Examples
Example 1: Moderate Cut for Male Lifter
Problem: A 185 lb male, 5 ft 10 in, age 28, active (lifts 4x/week), currently at 20% body fat, wants to cut to 12%.
Solution: BMR: 10 x 83.9 + 6.25 x 177.8 - 5 x 28 + 5 = 1,815 kcal\nTDEE: 1,815 x 1.725 = 3,131 kcal\nModerate deficit: -500 kcal\nCut calories: 3,131 - 500 = 2,631 kcal\nLean mass: 185 x 0.80 = 148 lbs\nProtein: 148 x 1.1 = 163g (652 kcal)\nFat: 83.9 x 0.7 = 59g (529 kcal)\nCarbs: (2,631 - 652 - 529) / 4 = 363g\nTarget weight: 148 / 0.88 = 168 lbs (lose 17 lbs)\nTimeline: 17 / 1.0 = 17 weeks
Result: Cut Calories: 2,631 | Protein: 163g | Fat: 59g | Carbs: 363g | ~17 weeks to goal
Example 2: Conservative Cut for Female
Problem: A 145 lb female, 5 ft 5 in, age 32, moderately active, at 28% body fat, targeting 22%.
Solution: BMR: 10 x 65.8 + 6.25 x 165.1 - 5 x 32 - 161 = 1,348 kcal\nTDEE: 1,348 x 1.55 = 2,089 kcal\nConservative deficit: -300 kcal\nCut calories: 2,089 - 300 = 1,789 kcal\nLean mass: 145 x 0.72 = 104 lbs\nProtein: 104 x 1.1 = 115g (459 kcal)\nFat: 65.8 x 0.7 = 46g (414 kcal)\nCarbs: (1,789 - 459 - 414) / 4 = 229g\nTarget weight: 104 / 0.78 = 134 lbs (lose 11 lbs)\nTimeline: 11 / 0.6 = 18 weeks
Result: Cut Calories: 1,789 | Protein: 115g | Fat: 46g | Carbs: 229g | ~18 weeks to goal
Frequently Asked Questions
What is the best calorie deficit for cutting while preserving muscle?
Research suggests that a moderate calorie deficit of 300 to 500 calories per day is optimal for preserving lean muscle mass while losing body fat. This rate produces approximately 0.5 to 1 pound of fat loss per week. A study published in the International Journal of Sport Nutrition found that athletes who lost weight at 0.7 percent of body weight per week retained more muscle and strength than those losing 1.4 percent per week. More aggressive deficits of 750+ calories can accelerate fat loss but increase the risk of muscle loss, hormonal disruption, and metabolic adaptation. The leaner you are, the smaller your deficit should be.
How much protein should you eat while cutting to prevent muscle loss?
During a calorie deficit, protein requirements increase compared to maintenance or bulking phases. Research recommends 1.0 to 1.3 grams of protein per pound of lean body mass to maximize muscle preservation during a cut. A meta-analysis in the Journal of the International Society of Sports Nutrition found that higher protein intakes during energy restriction significantly reduced lean mass loss. This higher protein intake also helps with satiety, keeping you feeling fuller on fewer total calories. Distributing protein intake evenly across 4 to 6 meals with at least 25 to 40 grams per serving optimizes muscle protein synthesis throughout the day.
How long should a cutting phase last?
A cutting phase typically lasts 8 to 16 weeks depending on how much fat you need to lose and how aggressive your deficit is. For most people aiming to drop from 18 to 20 percent body fat down to 10 to 12 percent, a 12 to 16 week cut is realistic. Extending a cut beyond 16 to 20 weeks increases the risk of metabolic adaptation, hormonal disruption, and psychological burnout. If you have a substantial amount of fat to lose, consider using diet breaks of 1 to 2 weeks at maintenance calories every 6 to 8 weeks. This helps normalize leptin levels, reduce cortisol, and maintain metabolic rate throughout the cut.
What is metabolic adaptation and how does it affect cutting?
Metabolic adaptation, sometimes called adaptive thermogenesis, is your body reducing energy expenditure in response to prolonged calorie restriction. Your basal metabolic rate can decrease by 10 to 15 percent beyond what would be predicted by weight loss alone. This happens through reduced non-exercise activity thermogenesis, lower thyroid hormone output, increased mitochondrial efficiency, and hormonal changes including decreased leptin and testosterone. To counteract metabolic adaptation, incorporate regular diet breaks at maintenance calories, use refeed days with higher carbohydrates, maintain resistance training intensity, and avoid extreme deficits. Reverse dieting after a cut helps restore metabolic rate.
Should you reduce carbs or fat when cutting calories?
Both approaches can work, but most evidence suggests keeping protein high, maintaining adequate fat at 0.6 to 0.8 grams per kilogram, and adjusting carbohydrates to fill remaining calories. Carbohydrates are most flexible because they are not essential in the same way protein and fat are. However, keeping carbs moderately high supports training performance and maintains an anabolic hormonal environment. Research published in the American Journal of Clinical Nutrition found no significant difference in body composition between low-carb and low-fat diets when protein and calories were equated. Choose the approach that is most sustainable and allows you to maintain workout intensity.
What is the minimum safe calorie intake during a cut?
Most health organizations recommend that males should not consume fewer than 1,500 calories per day and females should not go below 1,200 calories per day without medical supervision. These minimums help ensure adequate micronutrient intake and prevent severe metabolic adaptation. Very low calorie diets below these thresholds significantly increase the risk of nutrient deficiencies, gallstone formation, muscle loss, hormonal disruption, and disordered eating patterns. For active individuals and athletes, the minimum is often higher because training demands increase energy requirements. A better guideline is to keep your deficit at no more than 25 percent of your TDEE.