Step 1: Find your BMR (Mifflin-St Jeor)
Your basal metabolic rate (BMR) is the energy your body burns at complete rest. The most accurate widely-used formula is the Mifflin-St Jeor equation:
- Men:
(10 × weight kg) + (6.25 × height cm) − (5 × age) + 5 - Women:
(10 × weight kg) + (6.25 × height cm) − (5 × age) − 161
Step 2: Multiply by activity to get TDEE
Your total daily energy expenditure (TDEE) is BMR times an activity multiplier, the number of calories you burn in a typical day:
- Sedentary × 1.2
- Lightly active × 1.375
- Moderately active × 1.55
- Active × 1.725
- Very active × 1.9
TDEE is your maintenance intake. Eat this and your weight holds steady.
Step 3: Adjust calories for your goal
This is the only place a shred and a bulk differ at the calorie level:
- Shred (cut): TDEE − 500 kcal. A moderate deficit loses roughly half a kilo of fat per week without crashing your energy or muscle.
- Bulk: TDEE + 300 kcal. A lean surplus builds muscle while keeping fat gain slow and controllable.
Step 4: Split it into protein, carbs, and fat
Calories tell you how much; macros tell you what kind. Here's a reliable, evidence-based split:
- Protein:
1.8 g per kg of body weight, the same on a cut or a bulk, because protein protects muscle in both. (4 kcal/g) - Fat:
25%of your daily calories on a shred,28%on a bulk. (9 kcal/g) - Carbs: everything left over.
(daily calories − protein kcal − fat kcal) ÷ 4. Carbs fuel your training, so they take the remainder.
The calculator above runs exactly these four steps. Plug in your numbers and you'll have your daily targets in seconds.
How accurate is this?
These formulas are population estimates, real metabolism varies by genetics, sleep, stress, and training history. Treat the output as a confident starting point, then adjust based on what actually happens to your weight over 2 to 3 weeks. If you're not moving in the right direction, nudge calories by ±100 to 150 and reassess. This is exactly the kind of ongoing adjustment a real coach handles for you.
Frequently asked questions
How many calories should I eat to shred?
Take your TDEE and subtract about 500 kcal. That's a moderate deficit, sustainable, and gentle enough to keep your muscle and energy while you lose fat.
How much protein do I need on a bulk?
About 1.8 g per kg of body weight per day. Protein needs stay high on a bulk to turn your training and surplus into muscle rather than just fat.
Do my macros change as I lose weight?
Yes. As your weight drops, both your TDEE and your protein target (which is weight-based) fall too. Recalculate every few kilos, or let a coaching app like Mudabbir recompute targets for you automatically.