WhiskMath

Meal Prep Portion Calculator

Turn a daily calorie target and macro split into per-meal portions and totals for your whole prep.

kcal
meals
%
%
%
days
Per meal
500
calories
Per-meal macros
37.5g
protein · 50g carbs · 16.7g fat
  • Each day: 2000 kcal — 150g protein, 200g carbs, 66.7g fat.
  • Whole 5-day prep: 10000 kcal — 750g protein, 1000g carbs, 333.3g fat.
  • Macro energy values: protein and carbs are 4 calories per gram, fat is 9.
  • These are informational portioning estimates, not nutrition or dietary advice.
Save to Pinterest

How to use this calculator

  1. Enter your daily calorie target

    Type the total calories you are planning each day around.

  2. Set your macro split

    Enter the percentage of calories from protein, carbs and fat — they should add up to 100.

  3. Add meals and days

    Enter how many meals you eat per day and how many days you are prepping.

  4. Read your portions

    The calculator shows per-meal calories and macro grams, plus the totals for the whole prep period.

Recommended gear

As an Amazon Associate, WhiskMath earns from qualifying purchases. These picks don't cost you anything extra.

Escali Primo Digital Kitchen Scale

A digital scale makes portioning each meal to your gram targets quick and accurate.

$25

View on Amazon

Instant Pot Duo 7-in-1 Pressure Cooker

Batch-cooks proteins and grains so a week of prep comes together fast.

$80-100

View on Amazon

Calories per gram by macronutrient

MacronutrientCalories per gram
Protein4 calories
Carbohydrate4 calories
Fat9 calories

These are the standard Atwater factors. Alcohol, for reference, is about 7 calories per gram.

Tips & best practices

  • Treat the results as informational estimates — they are portioning math, not nutrition or medical advice.
  • Make sure your three macro percentages add up to 100 so the per-meal numbers line up with your target.
  • Use the whole-period totals to write your shopping list — buy proteins and staples in one go.
  • A kitchen scale makes hitting your per-meal gram targets far easier than eyeballing portions.
  • Cook proteins and grains in big batches, then portion them into containers so every meal is consistent.

Frequently asked questions

How many calories per gram are in each macro?
Protein and carbohydrates each provide about 4 calories per gram, and fat provides about 9 calories per gram. These are the standard Atwater factors this calculator uses.
How do I split calories into per-meal portions?
Divide your daily calorie target by the number of meals you eat. For example, 2000 calories across 4 meals is 500 calories per meal. The calculator then breaks each meal into protein, carb and fat grams.
What should my macro percentages add up to?
Your protein, carb and fat percentages should add up to 100, since together they account for all of your calories. The calculator will gently flag it if they do not, but it still shows the math.
How do I convert a macro percentage into grams?
Multiply your calorie target by the macro's percentage, then divide by its calories per gram. For 2000 calories at 30 percent protein, that is 2000 × 0.30 ÷ 4, which is 150 grams of protein.
Why calculate totals for the whole prep period?
Seeing the totals across all your days makes it easier to shop. If you know you need 1000 grams of protein for the week, you can buy the right amount of chicken, fish or tofu in one trip.
Can I use this for any macro split?
Yes. Whether you follow a higher-protein, higher-carb or balanced split, just enter your own percentages. The calculator does the arithmetic for whatever numbers you give it.
Does this calculator tell me what I should eat?
No. It only does the portioning math from numbers you provide. It does not set calorie targets or recommend a diet — those decisions are personal and best discussed with a qualified professional.
Is this nutrition or medical advice?
No. This tool provides informational portioning estimates only. It is not nutrition, dietary or medical advice, and it is not a substitute for guidance from a registered dietitian or doctor.

Related calculators

Pasta Serving Size Calculator

Work out exactly how much dry pasta to cook per person — for a side dish or a main course.

Open calculator

Pizza Calculator: How Much Pizza Per Person

Find out exactly how many pizzas to order for your group, based on guests, appetites and pizza size.

Open calculator

Catering Quantity Calculator

Plan how much food and drink to buy for an event — protein, sides, appetizers and drinks by guest count.

Open calculator

Grocery List Cost Estimator

Add up your grocery list before you shop — get an estimated total with a tax buffer and a cost per meal.

Open calculator

Cups to Grams Converter

Convert cups to grams for any baking ingredient — flour, sugar, butter, honey and more, each with its own weight.

Open calculator

Recipe Scaler

Double, halve, or resize any recipe to the exact number of servings you need — every ingredient scaled instantly.

Open calculator

Sources: Standard macronutrient energy values (Atwater factors).

Results are estimates for informational use. For food safety, always confirm meat doneness with a thermometer against current USDA guidance. WhiskMath does not provide medical or dietary advice.