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Macronutrient Calculator

Turn a daily calorie target into gram targets for protein, carbs, and fat — using goal-based presets or a custom split, with the math shown so you can adjust it.

Protein
165 g (30%)
Carbs
220 g (40%)
Fat
73 g (30%)
Energy densities: protein 4 kcal/g · carbs 4 kcal/g · fat 9 kcal/g (Atwater factors)

Goal-Based Macro Presets

PresetProteinCarbsFat
Balanced30%40%30%
High protein40%35%25%
Low carb35%20%45%
Endurance20%55%25%

Presets are starting points; grams per kilogram of bodyweight is the more precise way to set protein.

The Formula Behind the Result

  1. Enter your daily calorie target (from any TDEE estimate or diet plan you already have).
  2. Pick a preset split — balanced, high-protein, low-carb, or endurance — or set your own percentages.
  3. The calculator converts each percentage into grams using the standard energy densities.
  4. Results update live as you move sliders, with the gram math shown explicitly for each macro.
Formula & Technical Standard
Protein g = calories × P% ÷ 4 · Carbs g = calories × C% ÷ 4 · Fat g = calories × F% ÷ 9 (energy densities 4/4/9 kcal per gram).

Worked Example

Balanced split
Input: 2,200 kcal at 30/40/30 (P/C/F)
Output: 165 g protein · 220 g carbs · 73 g fat
Protein: 2,200 × 0.30 ÷ 4 = 165 g. Carbs: 880 kcal ÷ 4. Fat: 660 kcal ÷ 9 ≈ 73 g.
High-protein cutting split
Input: 1,800 kcal at 40/30/30
Output: 180 g protein · 135 g carbs · 60 g fat
Elevated protein during a calorie deficit helps preserve lean mass; 180 g is roughly 1.6–2.2 g/kg for a 82–113 kg range.

Common Questions

What percentage split should I choose?

There is no universally correct split. Evidence supports 1.6–2.2 g protein per kg bodyweight for active people; fat below ~20% of calories is unnecessary and can affect hormones; remaining calories fill with carbohydrate. Presets encode these patterns — adjust for preference.

Do macros matter more than total calories?

For weight change, total calories dominate. Macros matter for body composition, satiety, performance, and adherence — important, but secondary to the energy balance the calorie target captures.

Should I hit macros exactly every day?

Daily precision is unnecessary. Averaging within ±5–10 g over several days produces the same outcome; rigid daily tracking tends to hurt adherence without improving results.

Where do the 4/4/9 calorie factors come from?

The Atwater system, developed at the USDA in the late 19th century from metabolic experiments. Fiber and alcohol complicate the picture, which is why labels sometimes show slightly different effective values.

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