How big should my calorie deficit be for cutting?

A moderate cut uses a 15-20% deficit (about 2,000-3,000 kJ below TDEE), resulting in 0.5-0.75 kg of fat loss per week. An aggressive cut uses 20-25%, losing up to 1 kg per week. Larger deficits increase the risk of muscle loss, metabolic adaptation, and poor adherence.

Why is protein higher during a cut?

Higher protein (2.2-2.6 g/kg) during a calorie deficit helps preserve muscle tissue. When in a deficit, your body is more likely to break down muscle for energy. Elevated protein intake signals your body to maintain muscle while primarily burning fat stores.

How long should a cutting phase last?

Most cutting phases last 8-16 weeks. Longer cuts increase the risk of metabolic adaptation and muscle loss. If you need to lose a significant amount of fat, consider cycling between 8-12 week cut phases with 2-4 week maintenance phases (diet breaks).

Should I change my training while cutting?

Keep lifting heavy to signal your body to maintain muscle. Reduce training volume slightly (fewer sets) if recovery suffers, but maintain intensity (weight on the bar). Adding moderate cardio can increase your deficit without further reducing food intake.

Cutting Calculator

This Cutting Calculator helps you lose body fat while preserving as much muscle as possible. It calculates your optimal calorie deficit and macro split, with higher protein targets to protect lean mass during a cut. Choose between a moderate cut (15-20% deficit) for sustainable fat loss or an aggressive cut (20-25% deficit) for faster results.

Enter Your Details

Gender

Age

years

Weight

Height

Activity Level

Cut Intensity

How It Works

The calculator estimates your TDEE, then subtracts 15-25% to create a calorie deficit. Protein is set higher than maintenance at 2.2-2.6 g/kg - research shows elevated protein intake during a deficit significantly reduces muscle loss. Fat is set at 0.6-0.8 g/kg to maintain hormonal function, and carbohydrates fill the remaining calories to support training energy.

Quick Reference

Parameter	Moderate Cut	Aggressive Cut	Notes
Calorie Deficit	-15-20%	-20-25%	Below TDEE
Protein	2.2 g/kg	2.4 g/kg	Higher to preserve muscle
Fat	0.6-0.8 g/kg	0.6-0.8 g/kg	Minimum for hormonal health
Carbohydrates	Remainder	Remainder	Reduced but not eliminated
Weekly Fat Loss	0.5-0.75 kg	0.75-1.0 kg	Target rate
Muscle Loss Risk	Low	Moderate	Higher deficit = more risk
Duration	8-16 weeks	6-12 weeks	Include diet breaks
Recommended For	Most lifters	Experienced / leaner athletes	Start moderate
Training Volume	Maintain or slight reduction	Reduce volume, keep intensity	Never reduce weight on bar
Cardio	2-3 sessions/week	3-5 sessions/week	Low-moderate intensity preferred

A moderate cut is recommended for most people. Aggressive cuts are best suited for experienced lifters who are already relatively lean.

Frequently Asked Questions

How big should my calorie deficit be for cutting?: A moderate cut uses a 15-20% deficit (about 2,000-3,000 kJ below TDEE), resulting in 0.5-0.75 kg of fat loss per week. An aggressive cut uses 20-25%, losing up to 1 kg per week. Larger deficits increase the risk of muscle loss, metabolic adaptation, and poor adherence.
Why is protein higher during a cut?: Higher protein (2.2-2.6 g/kg) during a calorie deficit helps preserve muscle tissue. When in a deficit, your body is more likely to break down muscle for energy. Elevated protein intake signals your body to maintain muscle while primarily burning fat stores.
How long should a cutting phase last?: Most cutting phases last 8-16 weeks. Longer cuts increase the risk of metabolic adaptation and muscle loss. If you need to lose a significant amount of fat, consider cycling between 8-12 week cut phases with 2-4 week maintenance phases (diet breaks).
Should I change my training while cutting?: Keep lifting heavy to signal your body to maintain muscle. Reduce training volume slightly (fewer sets) if recovery suffers, but maintain intensity (weight on the bar). Adding moderate cardio can increase your deficit without further reducing food intake.

How This Is Calculated

BMR = (10 x weight in kg) + (6.25 x height in cm) - (5 x age) +/- gender offset TDEE = BMR x activity multiplier Cut Calories = TDEE x (1 - deficit %) Protein (g) = body weight (kg) x protein factor (2.2-2.4 g/kg) Fat (g) = body weight (kg) x 0.7 Carbs (g) = (Cut Calories - Protein kcal - Fat kcal) / 4 Weekly Fat Loss (kg) = (Daily Deficit kcal x 7) / 7,700

-15-20%: = Moderate cut deficit below TDEE
-20-25%: = Aggressive cut deficit below TDEE
2.2-2.4 g/kg: = Elevated protein to preserve lean mass during deficit
0.7 g/kg: = Fat target (mid-range of 0.6-0.8) for hormonal function
7,700 kcal/kg: = Approximate energy stored in 1 kg of body fat

Uses the Mifflin-St Jeor equation for BMR. Research from Eric Helms et al. (2014) supports protein intakes of 2.3-3.1 g/kg of lean body mass during caloric restriction. This calculator uses total body weight for simplicity.

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Disclaimer

This calculator provides estimates for informational purposes only and should not be considered medical advice. Individual results may vary based on factors not captured by these formulas. Consult a healthcare professional before making changes to your diet or exercise routine, especially if you have any existing health conditions.