Want the shortcut? Our free calculator does all of this for you in about 20 seconds.
But if you want to understand where your numbers come from (and you should, because that's what lets you adjust them later), here's the exact method in 4 steps.
Step 1: Find the Calories You Burn at Rest
This is your BMR (basal metabolic rate): the calories your body burns just keeping you alive. We use the Mifflin-St Jeor equation, one of the most widely used and accurate formulas:
Men: (10 × weight in kg) + (6.25 × height in cm) − (5 × age) + 5
Women: (10 × weight in kg) + (6.25 × height in cm) − (5 × age) − 161
Step 2: Add Your Activity Level
Multiply your BMR by how active you are. This gives you your total daily calories burned, also called your maintenance calories.
Mostly sitting, little exercise: about 1.2
Light (workouts 1 to 3 days a week): about 1.375
Moderate (workouts 3 to 5 days a week): about 1.55
Very active (hard workouts 6 to 7 days a week): about 1.725
Be honest here. Most people overestimate how active they are, and that's one of the most common reasons a plan doesn't work.
Step 3: Set Your Goal
Lose fat: eat about 20% fewer calories than maintenance.
Maintain: eat your maintenance calories.
Build muscle: eat about 10% more than maintenance.
Step 4: Split Your Calories Into Macros
Now turn that calorie number into grams of protein, carbs and fat, in this order:
Protein first: 0.8 grams per pound of body weight (1.8 g per kg). Protein comes first because it protects your muscle.
Fats next: 25% of your calories. Divide those calories by 9 to get grams.
Carbs fill the rest: subtract your protein and fat calories from your total, then divide by 4.
Let's Do One Together
Meet our example: a 40-year-old woman, 5'6" (167.6 cm), 170 lb (77.1 kg), who works out 1 to 3 days a week and wants to lose fat.
BMR: (10 × 77.1) + (6.25 × 167.6) − (5 × 40) − 161 = about 1,458 calories
Maintenance: 1,458 × 1.375 = about 2,004 calories
Fat loss target: 2,004 × 0.8 = about 1,600 calories
Protein: 170 × 0.8 = 136g (544 calories)
Fats: 25% of 1,600 = 400 calories ÷ 9 = 44g
Carbs: 1,600 − 544 − 400 = 656 calories ÷ 4 = 164g
Her daily targets: 1,600 calories | 136g protein | 164g carbs | 44g fat.
Remember: It's a Starting Point
Every formula is an estimate. Your real metabolism might run a little higher or lower. That's why the next step is to track your food accurately, watch your weight for 2 to 3 weeks, and adjust by about 100 to 200 calories if it isn't moving the way you want.
Skip the math and get your numbers now:
Then put them on a plate with our free Macro Cheat Sheet, which shows you the top macro foods to hit your targets.
The Macro Shred Start Here Series
How to Calculate Your Macros (you are here)
