Free Cut Calculator — Calories, Macros & Timeline
Calculate your personalized cutting calories, macro split, and fat-loss timeline. Powered by the Mifflin-St Jeor TDEE equation and Alpert fat oxidation limit to protect your muscle mass. Free, no signup required.
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1. Enter your stats. Input your current weight, goal weight, height, age, and sex. Body fat percentage is optional but improves accuracy — use it if you have a recent DEXA or caliper measurement.
2. Set your activity level. Be honest. Most people overestimate activity. "Moderately active" means 3-5 hard training sessions per week, not light walking.
3. Hit Calculate. The calculator outputs your daily calorie target, macro split (protein/fat/carbs), weekly fat loss rate, and total timeline to goal weight.
4. Track and adjust. Weigh daily, take a 7-day average, and compare to your target rate. If losing faster than planned, add 100-150 kcal. If slower, reduce by 100-150 kcal. Adjust every 2 weeks max.
What Is TDEE and Why It Matters for Cutting
TDEE (Total Daily Energy Expenditure) is the total calories your body burns each day. It includes your Basal Metabolic Rate (BMR) — calories burned at rest — multiplied by your activity factor.
To lose fat, you need to eat below your TDEE. The size of that deficit determines how fast you lose fat and whether you lose muscle alongside it. Our calculator uses the Mifflin-St Jeor equation, the most validated BMR formula in clinical research, to calculate your TDEE accurately.
Learn more: How to Calculate Your TDEE · Why TDEE Calculators Are Often Wrong
The Alpert Limit: How Fast Can You Safely Lose Fat?
The Alpert limit defines the maximum rate your body can oxidize fat for energy: approximately 22 kcal per pound of fat mass per day. Exceed this limit and your body must burn muscle for fuel — exactly what you want to avoid on a cut.
This is why lean people need smaller deficits than those with more fat to lose. At 15% body fat, your Alpert limit is much lower than at 25% body fat. Our calculator automatically caps your deficit at a safe level based on your estimated fat mass.
Read more: The Alpert Limit: How Fast Can You Safely Lose Fat? · How to Lose Fat Without Losing Muscle
Setting Macros for a Cut
| Macro | Target | Why |
|---|---|---|
| Protein | 1.0g / lb bodyweight | Muscle preservation in deficit |
| Fat | 25% of calories | Hormone production, fat-soluble vitamins |
| Carbs | Remaining calories | Training performance and recovery |
Related: How to Set Macros for Cutting · How Much Protein Per Day to Build Muscle
Frequently Asked Questions
How many calories should I eat on a cut?
Your cutting calories depend on your TDEE (Total Daily Energy Expenditure) minus a safe deficit. The maximum safe deficit is limited by the Alpert limit: 22 kcal per pound of fat mass per day. For most people, a moderate deficit of 500-750 calories below TDEE produces 1-1.5 lbs of fat loss per week.
How much protein do I need while cutting?
Research consistently shows that 1.0g of protein per pound of bodyweight is optimal for muscle preservation during a caloric deficit. This is higher than the general recommendation because your body is more likely to break down muscle tissue when in a deficit.
How long should a cut last?
A typical cut lasts 8-16 weeks, depending on how much fat you need to lose and your starting body fat percentage. Plan for 1-2 diet breaks (eating at maintenance for 1-2 weeks) every 8-12 weeks to restore hormones and prevent metabolic adaptation.
Will I lose muscle while cutting?
With adequate protein (1g/lb), continued resistance training at high intensity, and a deficit within the Alpert limit, trained individuals typically preserve 90-95% of their lean mass during a cut.
What is the Alpert limit?
The Alpert limit is the maximum rate at which the body can oxidize fat for energy: approximately 22 kcal per pound of fat mass per day. Exceeding this limit forces your body to burn lean mass (muscle) for energy. Our calculator ensures your deficit stays within this safe boundary.
How accurate is the Mifflin-St Jeor equation?
The Mifflin-St Jeor equation is the most validated BMR formula in clinical literature, accurate to within ±10% for most individuals. It outperforms the Harris-Benedict and Katch-McArdle equations in large-scale validations. For best results, use body fat percentage if you know it.