Skip to content
Calcapedia
Menu
Food & Kitchen

Macro Calculator

Find how many grams of protein, carbs and fat to eat each day and at each meal, from your calorie target and a ready-made or custom split.

Level: Grade 6

  • Common Core standard 6.RP.A.3.cFind a percent of a quantity as a rate per 100 (e.g., 30% of a quantity means 30/100 times the quantity); solve problems involving finding the whole, given a part and the percent.
  • Common Core standard 6.RP.A.3.bSolve unit rate problems including those involving unit pricing and constant speed.
Printable worksheet

Macro Calculator

Inputs
Calorie target

Used only to split the daily grams evenly across meals.

Result

Daily macros

100 g protein · 250 g carbs · 67 g fat

At about 2,000 kcal a day, this split works out to 100 g protein · 250 g carbs · 67 g fat. These are estimates to adjust over time, not a prescription.

Calorie target
2,000 kcal/day
Protein
100 g/day
Carbohydrate
250 g/day
Fat
67 g/day
Per meal (3 meals)
33 g protein · 83 g carbs · 22 g fat
Fiber reference (14 g per 1,000 kcal)
28 g/day
Where the calories come from (kcal)
  • Protein40020%
  • Carbohydrate1,00050%
  • Fat60030%

See the step-by-step solution ↓

How the calories are split
How the calories are split
MacronutrientShare of caloriesCalories (kcal)kcal per gramGrams per dayGrams per meal (3)
Protein20%400410033
Carbohydrate50%1,000425083
Fat30%60096722

Step-by-step solution

  1. Protein: take 20% of your calories, then divide by 4, because each gram gives about 4 kcal

    2,000×20%4=100 g

  2. Carbohydrate: take 50% of your calories, then divide by 4, because each gram gives about 4 kcal

    2,000×50%4=250 g

  3. Fat: take 30% of your calories, then divide by 9, because each gram gives about 9 kcal

    2,000×30%9=66.7 g

  4. Round each amount to the nearest gram

    100 g protein · 250 g carbs · 67 g fat

  5. Split each daily amount evenly across your 3 meals

    1003=33.3 g protein; 2503=83.3 g carbs; 66.73=22.2 g fat

  6. For a fiber guide, allow 14 g for every 1,000 kcal you eat

    2,0001,000×14=28 g

Test yourself

20 quick questions built from this calculator's formula: work out results, predict what happens when an input changes, and work backward from an answer. Every answer comes with the working.

What this calculator does

Find out how many grams of protein, carbs and fat to eat each day, and at each meal. You start from a daily calorie target. You also get a guide for how much fiber to aim for. Protein, carbohydrate and fat are called macronutrients, or macros for short. They supply almost all of the energy in food. Your macro split is the share of your daily calories that comes from each one. Turning that split into grams makes it easy to use, because food labels and tracking apps list grams, not percentages.

You can enter a calorie target you already have. Or the calculator can estimate one from your height, weight, age and activity level. Then it divides the calories using a ready-made split or your own percentages. The numbers are general estimates for planning, not medical or diet advice. If you have a health condition, are pregnant, or are making big changes to how you eat, talk to a doctor or registered dietitian.

Where it's used

Why this math matters outside the classroom:

  • Protein grams. With 30% of 2,000 kcal from protein, 600 kcal ÷ 4 kcal per gram is 150 g of protein.
  • Fat grams. A 30% fat share of 2,000 kcal is 600 kcal, which is about 67 g of fat at 9 kcal per gram.
  • Per meal. Dividing 150 g of protein across three meals gives 50 g at each one.
  • Meal prep. People prepping a week of lunches use their gram targets to portion out each container.
  • Reading labels. Shoppers compare a label's grams of carbohydrate, fat and protein with their per-meal split.

Grade level and standards: Grade 6; Common Core State Standards for Mathematics 6.RP.A.3.c, 6.RP.A.3.b. © Copyright 2010. National Governors Association Center for Best Practices and Council of Chief State School Officers. All rights reserved.

How to use it

  1. Choose whether to enter a calorie target you already know, or to estimate one from your body and activity level.
  2. If you're estimating, enter your details and pick a goal. You can keep your weight steady, or lose or gain slowly or at a steadier pace.
  3. Pick a macro split. Choose Custom to set your own carbohydrate, protein and fat percentages. They need to add up to 100%.
  4. Set how many meals you eat. Then read the grams of each macro per day and per meal, and the table showing how the calories are divided.

What the inputs mean

Calorie target
If you already track what you eat or have a target from a professional, enter it here. Otherwise, the calculator estimates it. It uses the Mifflin-St Jeor formula for what you burn at rest, multiplied by a standard activity factor. That's the same method as the TDEE calculator.
Sex
The published equations have separate versions for males and females.
Age
These equations were developed for adults.
Goal
Your goal raises or lowers your estimated maintenance calories by 250 or 500 kcal a day. It only applies when the target is estimated.
Macro split
Balanced is 50% carbohydrate, 20% protein and 30% fat. Lower carb is 25/30/45, and higher protein is 40/30/30. All three keep protein and fat within the ranges commonly suggested for adults. Lower carb is below the usual carbohydrate range on purpose.
Carbohydrate
Your own percentages can include decimals, but the three must add up to exactly 100%.
Meals per day
Splits each daily amount evenly. If you want snacks to carry part of the total, count them as meals here.

Formula and method

Protein (g) = calories × protein % ÷ 4
Carbohydrate (g) = calories × carbohydrate % ÷ 4
Fat (g) = calories × fat % ÷ 9
Estimated calories = BMR × activity factor + goal adjustment
Per meal = daily grams ÷ meals per day
Fiber reference (g) = calories ÷ 1,000 × 14

Each gram of protein or carbohydrate gives about 4 kcal (food calories), and each gram of fat about 9 kcal. These are the standard numbers used on nutrition labels, called the Atwater factors. Alcohol (about 7 kcal per gram) and fiber aren't counted separately here.

BMR is what your body burns at rest. When the target is estimated, BMR comes from the Mifflin-St Jeor formula: 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5 for men, or − 161 for women. The activity factor runs from 1.2 for days spent mostly sitting to 1.9 for hard physical work plus training.

Grams are rounded to the nearest gram. The table keeps the calories behind them, so you can see where each number comes from.

The fiber guide uses 14 g per 1,000 kcal. That's the basis of the Adequate Intake set by the Institute of Medicine and used in the Dietary Guidelines for Americans. When the target is estimated from your body, you also see protein per pound or kilogram of your weight. That lets you compare it with advice based on body weight. One example is the adult RDA (Recommended Dietary Allowance) of 0.8 g per kg.

Worked example

Someone with a 2,000 kcal daily target chooses the balanced split (50% carbohydrate, 20% protein, 30% fat).

  1. Protein: 2,000 × 20% = 400 kcal, and 400 ÷ 4 = 100 g.
  2. Carbohydrate: 2,000 × 50% = 1,000 kcal, and 1,000 ÷ 4 = 250 g.
  3. Fat: 2,000 × 30% = 600 kcal, and 600 ÷ 9 = 66.7 g, which rounds to 67 g.
  4. Over 3 meals: 100 ÷ 3 = 33 g protein, 250 ÷ 3 = 83 g carbs and 66.7 ÷ 3 = 22 g fat per meal.
  5. Fiber guide: 2,000 ÷ 1,000 × 14 = 28 g a day.

Result: The daily macros are 100 g protein, 250 g carbs and 67 g fat. That's about 33 g, 83 g and 22 g per meal, with a fiber guide of 28 g.

Understanding the result

Treat the grams as a daily average to aim for, not a strict rule. Landing within about 5 to 10 grams of each number is plenty for most people. Your weekly average matters more than any single day.

Protein is often the number people focus on most, because it supports muscle and tends to keep you full. If you want a protein number based on your body weight instead of calories, the protein calculator gives general g/kg ranges.

If your weight changes faster or slower than you planned over several weeks, adjust your total calories first. The split itself matters less than how many calories you eat compared with how many you burn.

Assumptions and limitations

  • Protein and carbohydrate give 4 kcal per gram, and fat gives 9.
  • An estimated target assumes an adult in fairly steady health who isn't pregnant. It also assumes the activity level you chose matches an average week.
  • The ready-made splits are general starting points chosen for this calculator. They aren't recommendations for any particular person.
  • The 4/4/9 numbers are averages. The real energy a food gives you depends on its fiber and how it's processed.
  • An estimated calorie target carries the uncertainty of the BMR formula and of the activity level you pick, which can be 10% or more.
  • The calculator doesn't account for health conditions, kidney health, diabetes, pregnancy, breastfeeding, or the needs of children and teens.

Frequently asked questions

Which macro split is best?

No single split suits everyone. Many people do well across a wide range, as long as they get enough calories and protein and can keep the diet up. Choose a split you can stick with. For advice that fits your health and goals, ask a registered dietitian.

How much protein do I need a day?

The adult Recommended Dietary Allowance is 0.8 g per kilogram of body weight, or about 0.36 g per pound. That's a minimum that covers basic needs for most healthy adults. Many active people eat more. When you estimate your target from your body, the calculator shows your protein per pound or kilogram, so you can compare. The protein calculator covers ranges based on body weight in more detail.

How many grams of each macro should I eat per meal?

Divide the daily grams by the number of meals, and the calculator does this for you. With 2,000 kcal on the balanced split and three meals, that's about 33 g protein, 83 g carbs and 22 g fat per meal. Your meals don't need to be exactly even. What matters most is the daily and weekly total.

Why does fat use 9 kcal per gram but protein and carbs use 4?

Fat packs more energy into each gram. A gram of fat gives a little over twice the energy of a gram of protein or carbohydrate. So the same number of calories from fat means fewer grams.

Should I count fiber and alcohol?

This calculator counts all carbohydrate at 4 kcal per gram and leaves alcohol out. Fiber gives less energy than other carbohydrate, and alcohol adds about 7 kcal per gram. So tracking apps may show slightly different totals.

Why does my estimated calorie target have a warning?

If cutting calories for weight loss takes the estimate below about 1,200 kcal a day for women or 1,500 kcal a day for men, the result shows a note. Health groups often advise against eating that little unless a doctor is guiding you.

How this calculator is checked

Method: Grams = calories × share ÷ energy density, using the general Atwater factors (4 kcal/g protein and carbohydrate, 9 kcal/g fat). Fiber reference of 14 g per 1,000 kcal (Institute of Medicine Dietary Reference Intakes; Dietary Guidelines for Americans). Optional target from Mifflin-St Jeor (1990) × conventional activity factors (1.2–1.9) ± 250/500 kcal. The calculation is covered by automated tests with known reference values and edge cases. Last updated 2026-10-18. Found a problem? Tell us.

Embed this calculator

Put this Macro Calculator on your own website or blog for free. Paste this code where you want it to appear: