Macro Calculator
Turn your daily calorie target into exact protein, carb, and fat grams for a balanced, low-carb, high-protein, or keto diet.
Not sure? Use our TDEE calculator to find your maintenance calories first.
Understanding the Macro Calculator
A macro calculator splits a daily calorie target into grams of protein, carbohydrate, and fat. It is for people following a structured diet, whether for fat loss, muscle gain, or maintenance, who want to know not just how much to eat but the right balance of macronutrients. You supply a calorie figure (often from a TDEE calculator) and choose or accept a macro ratio. The output is a daily gram target per nutrient. Numbers are general guidance, not a personalized medical or sports-nutrition prescription.
How it works
The tool relies on the energy density of each macro: protein and carbohydrate each provide 4 calories per gram, fat provides 9. You pick a percentage split, for example 30 percent protein, 40 percent carbs, 30 percent fat. It multiplies your total calories by each percentage to get calories per macro, then divides by that macro's calories-per-gram to get grams. Many people instead anchor protein to body weight (around 1.6-2.2 g/kg for active individuals) and fill the rest with carbs and fat. Read the grams as daily targets to hit on average, not rigid limits.
Worked example
On a 2000 kcal/day target with a 30/40/30 protein/carb/fat split: protein = (2000 x 0.30) / 4 = 150 g; carbs = (2000 x 0.40) / 4 = 200 g; fat = (2000 x 0.30) / 9 = approximately 67 g. That is 600 kcal from protein, 800 from carbs, and 600 from fat, summing back to 2000 kcal, giving a clear daily plate target.
Tips & common mistakes
- Prioritize protein for muscle retention; 1.6-2.2 g/kg of body weight suits most active people.
- Keep fat at roughly 20 percent of calories or more to support hormones; do not cut it to near zero.
- Macro ratios are flexible; consistency with calories matters more than hitting a perfect split.
- Fiber falls under carbs but is not interchangeable with sugar; favor whole-food carb sources.
- Athletes, diabetics, and those with kidney conditions should get tailored advice from a professional.
Sources & methodology
- • Institute of Medicine — Dietary Reference Intakes, Acceptable Macronutrient Distribution Ranges (https://www.nationalacademies.org)
- • International Society of Sports Nutrition — protein position stand (https://jissn.biomedcentral.com)
Related tools
Reviewed by the TopOpenTools editorial team · Last updated June 2026. These tools provide general estimates for educational purposes only and are not financial, tax, insurance, investment, or medical advice. Verify important decisions with a qualified professional.
How to Use This Calculator
- 1Enter your daily calorie target (find it with the TDEE calculator).
- 2Pick a diet style that fits your goal.
- 3Click Calculate Macros to see your grams of protein, carbs, and fat.
Frequently Asked Questions
How are macros calculated?
We split your daily calorie target by the chosen ratio, then convert to grams using 4 kcal per gram for protein and carbs and 9 kcal per gram for fat.
Which diet ratio should I pick?
Balanced (30/40/30) suits most people. Low-carb and high-protein support fat loss and muscle retention; keto (very low carb, high fat) is for those following a ketogenic diet. There is no single best ratio — pick what is sustainable for you.
Where do I get my calorie target?
Use our TDEE calculator to find your maintenance calories first, then enter that number (or a deficit/surplus of it) here.
Is this nutritional advice?
No. These are general estimates for information only. Consult a registered dietitian for a personalized plan.