Protein grams = body weight × g/kg. Protein calories = protein grams × 4. Fat calories = total calories × fat %. Fat grams = fat calories ÷ 9. Carbohydrate grams = remaining calories ÷ 4.
Worked example
At 2,200 kcal, 80 kg body weight, 1.6 g/kg protein and 25% fat, protein is 128 g, fat is about 61 g and carbohydrate is about 284 g.
Professional note
Master’s Tip: choose protein first, then fat, then let carbohydrate fill the remaining energy budget.
Regional and unit assumptions
General nutrition planning estimate. Clinical nutrition needs require qualified advice.
Assumptions and limitations
Protein and carbohydrate are estimated at 4 kcal/g and fat at 9 kcal/g.
The result is nutrition planning arithmetic, not medical advice.
If protein plus fat exceed total calories, carbohydrate is shown as zero.
Methodology & Accuracy
How this calculator is checked
CalculationTime pages are built around visible arithmetic: the formula, assumptions, worked example and practical limitations are shown so the result can be checked rather than simply trusted.
Formula used
Protein grams = body weight × g/kg. Protein calories = protein grams × 4. Fat calories = total calories × fat %. Fat grams = fat calories ÷ 9. Carbohydrate grams = remaining calories ÷ 4.
Standard or basis
General nutrition planning estimate. Clinical nutrition needs require qualified advice.
Where a calculator follows a named legal, trade or industry standard, that standard is cited visibly. Otherwise the page uses transparent general arithmetic and states its limits.
Master's Tip
Master’s Tip: choose protein first, then fat, then let carbohydrate fill the remaining energy budget.
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