What This Calculator Does
The Microapp Macro Calculator computes your daily protein, carb, and fat targets based on your stats, activity level, body composition goal, and chosen macro preset. It uses the most validated formulas in nutrition science: Mifflin-St Jeor for BMR, the standard activity multipliers for TDEE, and ±500 kcal for cut/bulk adjustments.
• BMR: 10×70 + 6.25×175 − 5×30 + 5 = 1,648 kcal
• TDEE: 1,648 × 1.55 = 2,555 kcal at moderate activity
• Calorie target: 2,555 − 500 = 2,055 kcal/day for ~1 lb/week loss
• Carbs (40%): 2,055 × 0.40 / 4 = 206 g
• Protein (30%): 2,055 × 0.30 / 4 = 154 g
• Fat (30%): 2,055 × 0.30 / 9 = 69 g
Hit these averages over a week and you'll see the predicted weight change.
BMR, TDEE, and the Calorie Target
BMR (Basal Metabolic Rate) — the calories your body burns at complete rest, just to maintain organ function. Mifflin-St Jeor (1990) is the most accurate of the common BMR formulas per medical literature. Different formulas (Harris-Benedict, Katch-McArdle) give different numbers; Mifflin-St Jeor is the modern standard.
TDEE (Total Daily Energy Expenditure) — BMR multiplied by an activity factor:
| Activity level | Multiplier | Description |
|---|---|---|
| Sedentary | ×1.2 | Desk job, no intentional exercise |
| Lightly active | ×1.375 | Light exercise 1-3 days/week |
| Moderately active | ×1.55 | Moderate exercise 3-5 days/week |
| Very active | ×1.725 | Hard exercise 6-7 days/week |
| Extra active | ×1.9 | Very hard exercise + physical job |
Calorie target — TDEE plus or minus a goal adjustment:
- Cut: TDEE − 500 kcal/day → ~1 lb (0.45 kg) per week of fat loss
- Maintain: TDEE → weight stable
- Bulk: TDEE + 500 kcal/day → ~1 lb per week of weight gain (mostly muscle if training, mostly fat if not)
The Four Macro Presets
Balanced (40C/30P/30F): The default. Works for most people most of the time. Enough carbs for high-intensity training, enough protein for body composition goals, enough fat for hormonal health.
High-protein (30C/40P/30F): Ideal during cutting. Protein increases satiety, preserves muscle in a calorie deficit, and has the highest thermic effect (the body burns more calories digesting protein than carbs or fat).
Low-carb (20C/40P/40F): Suits people who feel better with fewer carbs (some report better energy, less hunger). Doesn't have a magic fat-loss advantage over higher-carb diets at the same total calories — but the higher fat content increases satiety for some people.
Keto (5C/25P/70F): A metabolic state (ketosis) requiring very low carb intake (typically <50 g/day). The body shifts to producing ketones from fat as the primary fuel. Some people thrive on it; others hate it. Useful for specific medical conditions (epilepsy, type 2 diabetes); not required for fat loss.
How Much Protein Do You Actually Need?
| Goal | Protein target |
|---|---|
| Sedentary, no fat loss goal | 0.8-1.0 g/kg of body weight (RDA minimum) |
| Fat loss while preserving muscle | 1.6-2.2 g/kg of body weight |
| Muscle gain (bulking) | 1.6-2.0 g/kg of body weight |
| Athlete in heavy training | 1.8-2.2 g/kg of body weight |
The "high-protein" preset typically delivers 1.5-2.0 g/kg for most users. Going dramatically higher (3+ g/kg) doesn't add benefit and crowds out other macros. The myth that high protein "damages kidneys" is false in healthy adults — only relevant for those with pre-existing kidney disease.
What Macro Splits Don't Determine
The macro split affects body composition outcomes only at the margins. The single dominant variable for fat loss is total calorie deficit. The macro split matters for:
- Muscle preservation in a deficit: high protein is meaningfully better than low protein
- Satiety and adherence: some people stick to low-carb easier; others stick to balanced easier
- Athletic performance: very low-carb impairs high-intensity training
- Hormonal health: very low-fat diets (under 20% of calories) can disrupt hormones
Within those constraints, eat what you can sustain. The "best" diet is the one you'll actually do for years.
Common Mistakes
Treating the calorie target as exact. Mifflin-St Jeor has ±10% individual variance. Activity multipliers are approximations. Track results over 2-4 weeks and adjust by 200-300 kcal if reality doesn't match the prediction.
Hitting macros perfectly every day. Average matters more than daily. Hit your weekly average ±5%; daily variance of 10-20% is fine. Trying to nail exact macros daily burns most people out within weeks.
Under-eating during cutting. The "more deficit = faster results" thinking backfires. Aggressive deficits (>1 lb/week) accelerate muscle loss, hormonal disruption, and binge cycles. Sustainable cuts at 1 lb/week beat starvation diets at 2-3 lb/week over any meaningful timeframe.
Forgetting that scale weight ≠ body composition. A 5 lb gain might be 3 lb muscle + 2 lb water. Track waist circumference, photos, and how clothes fit alongside scale weight.
Eating "clean" but not tracking. Quinoa and almonds are healthy but extremely calorie-dense. Many people fail to lose weight on "clean" diets because they're eating 500 calories of nuts/avocado/oils on top of the rest. Calories rule.
Educational Tool — Not Nutritional Advice
This calculator implements the standard nutrition-science formulas with population-average assumptions. Individual variance is significant. For specific medical conditions, athletic competition prep, eating disorder recovery, pregnancy, or other special situations, work with a registered dietitian (RD) — not a calculator.
Related Tools
Use the TDEE Calculator standalone if you only want the calorie number. The BMI Calculator tracks general weight category. The One Rep Max Calculator handles the strength training side of body composition planning.