How to Calculate Grocery Quantities From Recipe Servings

A recipe tells you what ingredients are needed for one batch.

A grocery list needs to tell you how much food to buy for the number of portions you actually plan to make.

Those are not always the same thing.

If a recipe serves six but you need four portions, you probably do not need the full ingredient list.

If it serves four but you need dinner for four plus four leftover lunches, you need more than one batch.

The basic calculation is:

Then:

For example, a recipe serves four and uses:

• 400 g chicken
• 200 g rice
• 300 g vegetables

You need six portions.

Scaling factor:

New quantities:

Chicken:

Rice:

Vegetables:

Those are the quantities the scaled recipe requires.

But your grocery calculation is not finished yet.

You still need to:

1. Repeat the calculation for your other recipes.
2. Combine ingredients used in more than one meal.
3. Subtract food already at home.
4. Adjust for edible or cooking yield when relevant.
5. Convert the final quantities into real store packages.
6. Decide what happens to package remainders.

USDA’s Food Buying Guide uses the same general relationship between recipe yield, serving size, and the amount of food that must be purchased, while also accounting for differences between food as purchased and food actually available for serving.

Start with the number of portions you actually need

Do not scale the recipe until you know what the finished food needs to cover.

Suppose a recipe says:

Serves 4

Ask:

• How many people are eating dinner?
• Is anyone eating elsewhere?
• Do I want leftovers?
• Will leftovers become lunch?
• Am I freezing portions?
• Does my household actually get four useful portions from this recipe?

For example:

Dinner for two:

2 portions

Tomorrow’s lunches for both:

2 portions

Total needed:

4 portions

No scaling is required.

Now suppose dinner is for three and you want two lunches.

Total:

A four-serving recipe needs to be increased.

Use this first formula

Example:

Current dinner:

4 portions

Tomorrow’s lunches:

2 portions

Freezer:

2 portions

Total required:

If the recipe serves four:

Make:

2 recipe batches

Do not create leftover portions automatically

If a recipe serves six and only four people need dinner, do not immediately assume you should make all six portions.

Ask where the other two will go.

Possible destinations:

• Tomorrow’s lunch
• Another dinner
• Freezer
• Another household member

If none applies, scaling the recipe down may be more useful.

The core recipe scaling formula

Use:

Then multiply every scalable ingredient by that factor.

Example 1: Scaling down

Recipe serves:

6

You need:

3

Scaling factor:

Original chicken:

600 g

New chicken:

Original rice:

300 g

New rice:

Original vegetables:

450 g

New vegetables:

You are making half the recipe.

Example 2: Scaling up

Recipe serves:

4

You need:

10

Scaling factor:

Original pasta:

400 g

Scaled pasta:

Original tomato sauce:

500 g

Scaled sauce:

Original vegetables:

300 g

Scaled vegetables:

Recipe servings are planning units, not always personal nutrition prescriptions

A recipe’s stated serving count tells you how the recipe author divided the batch.

It does not necessarily mean that serving is exactly the amount every person in your household should eat.

Likewise, FDA explains that serving sizes shown on Nutrition Facts labels reflect amounts people typically consume and are not recommendations for how much an individual should eat.

If a recipe says:

Serves 6

but your household consistently gets:

4 actual main-meal portions

use the observed four-portion yield for future grocery planning.

Record your actual recipe yield

This can make your grocery quantities much more accurate over time.

For example:

Recipe title:

Chicken pasta

Published yield:

6 servings

Your household’s usual yield:

4 dinner portions + 1 smaller lunch portion

For practical planning, you might record:

5 usable household portions

Next time you need:

10 portions

Scaling factor:

Rather than:

Your own kitchen history may better predict what you actually need.

Separate recipe yield from package serving size

Suppose a pasta package says:

8 servings per container

while your recipe says:

serves 4

These numbers answer different questions.

The package serving count describes the standardized Nutrition Facts serving size.

The recipe yield describes how the finished recipe is divided.

FDA specifically notes that one package can contain multiple labeled servings and that label serving sizes are not individualized eating recommendations.

For the grocery list, follow the amount of the ingredient required by your scaled recipe.

Scale each recipe before combining the grocery list

Suppose your weekly plan contains:

Recipe A: Chicken bowls

Original yield:

4 portions

Need:

6 portions

Recipe B: Chicken pasta

Original yield:

6 portions

Need:

3 portions

Do not combine the original ingredient lists first.

Scale each recipe separately.

Then combine the results.

Example

Chicken bowls

Original recipe:

4 servings

Chicken:

400 g

Need:

6 servings

Scale:

Chicken needed:

Chicken pasta

Original recipe:

6 servings

Chicken:

600 g

Need:

3 servings

Scale:

Chicken needed:

Weekly chicken requirement

Now subtract freezer stock.

If you already have:

250 g chicken

Grocery requirement:

That is how recipe servings become a shopping quantity.

Combine repeated ingredients across recipes

This is one of the most important steps.

Suppose three recipes require onions.

Scaled quantities:

Recipe 1:

1.5 onions

Recipe 2:

2 onions

Recipe 3:

1 onion

Weekly onion requirement:

You might buy:

5 onions

depending on size and how they are sold.

Do not list:

• Onions for Recipe 1
• Onions for Recipe 2
• Onions for Recipe 3

as separate purchases without totaling them.

That can easily lead to duplicate buying.

Build an ingredient master list

After scaling every recipe, create one combined table.

This table converts individual recipes into one grocery requirement.

Then subtract inventory

Do not shop from the weekly total yet.

Check:

• Refrigerator
• Freezer
• Pantry

EPA recommends checking existing food first and planning purchases only for what upcoming meals actually require.

Suppose your master list says:

Chicken:

900 g

Rice:

500 g

Onions:

5

Tomatoes:

900 g

Yogurt:

250 g

You already have:

Chicken:

250 g

Rice:

300 g

Onions:

2

Tomatoes:

200 g

Yogurt:

100 g

Your actual shopping list becomes:

Chicken

Rice

Onions

Tomatoes

Yogurt

That is a grocery list.

Use this complete grocery formula

For each ingredient:

Or:

Where:

G = grocery amount to buy

R = original recipe ingredient quantity

S = scaling factor for that recipe

I = existing usable inventory

The Σ symbol simply means:

add that ingredient across every recipe where it appears.

Example with three recipes

Chicken appears in:

Recipe 1:

400 g × 1.5 = 600 g

Recipe 2:

300 g × 2 = 600 g

Recipe 3:

500 g × 0.5 = 250 g

Total:

Freezer inventory:

450 g

Need to buy:

Now you know a 1 kg purchase matches the plan.

Count non-recipe meals too

A weekly grocery list usually contains food that is not part of formal recipes.

For example:

• Eggs for breakfast
• Yogurt
• Fruit
• Sandwich bread
• Snacks
• Milk
• Simple lunches

Add those separately.

Your grocery calculation is therefore:

Scaled recipe ingredients + non-recipe meal ingredients – existing inventory

Do not assume that converting dinner recipes into a shopping list automatically covers the entire week.

Example

Scaled dinner recipes need:

Eggs:

6

Breakfast plan needs:

Eggs:

8

Total weekly eggs:

Refrigerator:

4

Need:

If the store sells a dozen:

Buy:

12

Expected carry-forward:

2 eggs

Count the same ingredient only once in the final shopping list

If yogurt appears in:

• Breakfast
• Curry
• Sauce
• Snack

combine it.

Example:

Breakfast:

600 g

Recipe A:

150 g

Recipe B:

100 g

Snacks:

300 g

Total:

1,150 g

Inventory:

200 g

Need:

950 g

You might choose a 1 kg package if that fits the product and planned use.

Convert fractions into practical shopping units

Scaling recipes often creates amounts such as:

1.5 onions

2.25 peppers

0.75 cans

The store does not always sell fractional units.

You need to translate the recipe calculation into something purchasable.

Example: onions

Need:

4.5 onions

Buy:

5 onions

Example: cans

Need:

2.4 cans

If cans cannot be purchased fractionally:

Buy:

3 cans

Then:

becomes a package remainder requiring another use or appropriate storage after opening.

Do not round every recipe independently

This is an easy way to overbuy.

Suppose three recipes each require:

0.5 onion

If you round every recipe separately:

Recipe 1 → 1 onion Recipe 2 → 1 onion Recipe 3 → 1 onion

You buy:

3 onions

But total requirement is:

A practical purchase may be:

2 onions

Always combine first.

Then round.

The correct order is important

Use this sequence:

1. Scale each recipe.

2. Combine identical ingredients.

3. Add non-recipe uses.

4. Subtract inventory.

5. Convert to store packages.

Do not round quantities or choose packages before the ingredients have been combined.

Handle volume measurements carefully

A recipe may list:

• 1 cup rice
• 2 tablespoons oil
• 1 cup yogurt

You can scale those directly when using the same measuring system.

Example:

Original recipe:

1.5 cups rice

Scale factor:

2

New amount:

3 cups

That is mathematically fine.

For shopping, however, weight can be easier when the store package is sold in grams or kilograms.

If your specific ingredient provides a reliable weight conversion on its package or you have measured it yourself, you can convert the total into weight.

Avoid using one universal cup-to-gram conversion across different foods.

One cup of rice does not weigh the same as one cup of flour, yogurt, spinach, or oil.

Keep units consistent within an ingredient

Suppose Recipe A requires:

300 g chicken

and Recipe B lists:

1 pound chicken

You cannot add:

300 + 1

Convert one unit first.

Similarly:

2 cups rice + 300 g rice

requires a conversion before combining.

For repeat recipes, it can help to standardize the ingredient into one household unit such as:

• Grams
• Milliliters
• Pieces
• Cans

Use weight for ingredients sold by weight

Weight can be particularly helpful for:

• Meat
• Rice
• Pasta
• Cheese
• Produce
• Bulk foods

Example:

Three recipes require cheese:

100 g 175 g 75 g

Total:

350 g

Inventory:

100 g

Need:

250 g

Now compare that with the cheese package sizes at the store.

Use count where count is easier

For:

• Eggs
• Apples
• Lemons
• Tortillas
• Cans
• Individual yogurt cups

count may be more useful.

Example:

Recipe 1:

3 eggs

Recipe 2:

2 eggs

Breakfast:

6 eggs

Total:

11 eggs

Inventory:

3

Need:

8 eggs

Package:

12

Buy:

12

Expected carry-forward:

4

Scaling spices needs practical judgment

Mathematically, you can multiply spices by the same scaling factor.

For example:

Original:

1 teaspoon chili powder

Scale factor:

2

Mathematical result:

2 teaspoons

That may be a perfectly reasonable starting point.

However, flavoring ingredients such as:

• Salt
• Chili
• Hot sauce
• Strong spices
• Acid
• Extracts

may be better adjusted gradually when a recipe is scaled substantially.

For grocery shopping, this usually matters less because these ingredients are often pantry staples.

The larger issue is whether you need to buy them at all.

Do not buy a whole spice jar because the recipe requires one teaspoon until you check the pantry

Your recipe master list may say:

Cumin:

3 teaspoons

Before adding cumin to the shopping list, check the kitchen.

EPA specifically recommends checking pantry supplies before purchasing ingredients for planned meals.

This can eliminate many small duplicate purchases.

Pantry staples should be treated differently from one-use perishables

Suppose your recipes require:

Rice

450 g

Package:

1 kg

Fresh herbs

20 g

Package:

50 g

The rice remainder is generally straightforward pantry inventory when stored appropriately.

The herb remainder is more perishable and may need another planned use.

Therefore, package mismatch matters more for some ingredients than others.

Calculate package remainder after scaling

Use:

Example:

Yogurt required:

750 g

Existing:

100 g

Need:

650 g

Package available:

1,000 g

Closing quantity:

Now decide:

• Breakfast
• Snack
• Sauce
• Carry forward if storage allows

Do this before shopping when the ingredient is perishable.

A lower unit price does not eliminate package waste

Suppose your recipes require:

300 g spinach

Store offers:

500 g package.

The extra:

200 g

should have a destination.

If it does not, another vegetable, smaller package, frozen alternative, or recipe adjustment may fit better.

EPA’s current guidance prioritizes preventing food from being wasted and recommends buying only what planned meals require.

Food as purchased may not equal usable recipe quantity

Some ingredients lose weight through:

• Peeling
• Trimming
• Bones
• Cores
• Shells
• Cooking

USDA’s Food Buying Guide explicitly distinguishes food as purchased from the amount available after preparation and provides yield factors for this purpose.

This matters when the recipe requires:

500 g usable food

but the store sells an ingredient containing substantial waste.

Example: edible yield

Suppose a recipe needs:

900 g peeled, usable produce

and your reliable yield factor for the purchased product is:

0.75

Purchase requirement:

You need to buy approximately:

1.2 kg

not 900 g.

USDA demonstrates this exact style of calculation in its Food Buying Guide, dividing the amount needed for the recipe by the expected yield from the food as purchased.

Use the yield formula when necessary

Example:

Recipe requires:

600 g usable ingredient

Yield:

80%, or 0.80

Purchase amount:

This becomes especially useful for:

• Bone-in meats
• Whole produce requiring trimming
• Foods with shells
• Ingredients with significant preparation loss

A later topic in this series covers edible yield in greater depth, so you do not need to apply yield adjustments to every minor ingredient.

Raw and cooked recipe amounts need attention too

Suppose one recipe says:

400 g cooked chicken

but you are buying:

raw chicken

Those are different weights.

You need an appropriate cooking yield to estimate the raw purchase amount.

For example, if your measured yield is:

75%

and you need:

400 g cooked

Raw amount:

400 ÷ 0.75 ≈ 533 g

The 75% is only an example.

Actual cooking yield depends on the food and preparation method.

Do not apply one yield percentage to every ingredient

USDA’s Food Buying Guide uses food-specific yield information because yields vary.

Your own observed yield can also be useful for foods you cook frequently.

Do not assume:

every meat loses 25%

or:

every vegetable has 80% edible yield

without evidence.

How to scale a 4-serving recipe to 2 servings

Scaling factor:

Original:

Chicken: 500 g Rice: 250 g Vegetables: 400 g Sauce: 200 mL

Scaled:

Chicken:

250 g

Rice:

125 g

Vegetables:

200 g

Sauce:

100 mL

Now compare those quantities with existing ingredients and store package sizes.

How to scale 4 servings to 6

Scaling factor:

Original:

Pasta: 400 g Tomato sauce: 500 g Beans: 2 cans Vegetables: 300 g

Scaled:

Pasta:

600 g

Tomato sauce:

750 g

Beans:

3 cans

Vegetables:

450 g

How to scale 6 servings to 4

Scaling factor:

Original chicken:

900 g

New chicken:

900 × 0.667 ≈ 600 g

Original rice:

450 g

New rice:

450 × 0.667 ≈ 300 g

Original vegetables:

600 g

New vegetables:

600 × 0.667 ≈ 400 g

Minor rounding is usually reasonable for ordinary home cooking.

How to scale 8 servings to 5

Scaling factor:

Original ingredient:

1,000 g potatoes

Scaled:

Original:

800 g chicken

Scaled:

Original:

4 peppers

Scaled:

The grocery list might therefore use:

3 peppers

after ingredients have been combined with other recipes.

Do not round 2.5 peppers immediately if another recipe needs peppers

Suppose:

Recipe A:

2.5 peppers

Recipe B:

1.5 peppers

Total:

4 peppers

If you rounded first:

Recipe A → 3 Recipe B → 2

You would buy:

5

Combining first saves one unnecessary pepper.

Recipes with eggs may not scale perfectly to tiny fractions

Suppose a recipe requires:

1 egg

and scaling mathematically produces:

0.5 egg

You have options:

• Beat one egg and use approximately half by weight or volume.
• Make the full recipe if the extra food has a destination.
• Choose a nearby practical recipe yield.
• Use another recipe better suited to a smaller batch.

Do not distort every other ingredient simply because one egg is inconvenient to divide.

Baking requires more caution than everyday cooking

Scaling a rice bowl from four servings to six is usually straightforward.

Scaling:

• Bread
• Cakes
• Pastries
• Custards
• Recipes dependent on pan dimensions

may require more care because ingredient ratios, pan size, cooking time, and structure interact.

For these recipes, use a tested scaled recipe when precision matters rather than assuming that arithmetic alone guarantees the same result.

For ordinary grocery planning, you can still calculate how much ingredient is required, but the cooking method may need adjustment.

Build the grocery list after every recipe is scaled

Suppose your plan contains four recipes.

Recipe 1

Chicken bowls, 6 portions

Recipe 2

Bean pasta, 4 portions

Recipe 3

Chicken tacos, 5 portions

Recipe 4

Soup, 8 portions

After scaling each one, create:

Then subtract inventory.

Example inventory subtraction

Already have:

Chicken:

400 g

Beans:

1 can

Rice:

300 g

Pasta:

500 g

Tomatoes:

200 g

Onions:

2

Peppers:

1

Carrots:

100 g

Yogurt:

150 g

Actual grocery requirements:

Chicken:

Beans:

Rice:

Pasta:

Tomatoes:

Onions:

Peppers:

Carrots:

Yogurt:

Notice:

Pasta disappears from the grocery list completely.

That is the benefit of checking existing food before buying. EPA recommends exactly this inventory-first approach.

Do not subtract ingredients that are already assigned elsewhere

Suppose you have:

500 g chicken in the freezer

but:

300 g is already reserved for tonight’s meal outside this weekly plan

Your usable inventory for the new recipes is only:

200 g

Inventory means:

food genuinely available for these meals

not merely food physically present.

Use recipe portions to calculate meal coverage

Suppose a freezer container contains:

3 portions of chili

and your weekly plan calls for a chili dinner for two.

That freezer meal already covers:

2 portions

You do not need to buy ingredients for another full chili recipe.

The third portion can become:

• Lunch
• Another meal
• Continued freezer inventory

Sometimes it is easier to subtract a complete prepared meal than to reverse-engineer its ingredient quantities.

Do not reverse-engineer every leftover

If you already have:

2 portions chicken curry

you do not need to calculate how many grams of raw chicken, onions, sauce, and rice those portions represent.

Simply mark:

Tuesday dinner covered

Then remove Tuesday’s recipe from the new grocery calculation.

This keeps the system practical.

Make recipe ingredient names consistent

One recipe may say:

yellow onion

Another:

onion

Another:

medium onion

If you are happy using the same onion type in all three meals, combine them.

Likewise:

• Bell pepper / red pepper
• Chickpeas / canned chickpeas
• Greek yogurt / plain yogurt, when interchangeable for the recipe
• Rice types, when interchangeable

Do not combine ingredients when the distinction matters to the dish.

Watch for duplicated units in recipe apps or spreadsheets

You might end up with:

Milk, 500 mL

and:

Milk, 2 cups

on separate lines.

Convert them before shopping.

Likewise:

Chicken, 0.5 kg

and:

Chicken, 300 g

should become:

800 g total

before inventory subtraction.

Package conversion comes after the exact ingredient calculation

Suppose you need:

850 g chicken

Store packages:

500 g each

Packages needed:

Buy:

2 packages

Total purchased:

1,000 g

Remainder:

150 g

Assign that remainder.

Use a package formula

“Ceiling” means round upward to the next whole package.

Example:

Need:

2.2 cans

You cannot buy:

0.2 of a sealed can

Buy:

3 cans

But only after all recipe uses for that ingredient have been combined.

Sometimes one package can cause a useful recipe adjustment

Suppose your scaled recipe requires:

450 g ground meat

but the store package is:

500 g

You may choose to use all 500 g if:

• The recipe can comfortably absorb the difference.
• It produces a useful extra portion.
• The change does not distort the meal.

But do not automatically alter every recipe just to empty the package.

The remaining 50 g could also be combined with another meal or frozen appropriately.

Package size should not secretly determine every serving

The logic should be:

Meal needs → recipe scale → grocery quantity → package choice

not:

Package size → force everyone to eat that amount

This distinction is especially important for larger packages.

A lower unit price should be evaluated after the recipe quantity is known

Suppose recipes require:

700 g yogurt

Options:

500 g for $3 1,000 g for $5

The larger package may have a lower unit price.

But your plan needs only 700 g.

Ask whether the remaining:

300 g

has another use.

If yes, the large tub may make sense.

If no, the quantity calculation tells you there is a package mismatch to manage.

Create a package remainder column

This is one of the easiest ways to stop a recipe-based grocery list from creating half-used packages.

A complete three-recipe example

Suppose two people want three dinners, and each dinner should also provide one lunch.

Therefore, each recipe needs:

3 portions

Recipe 1: Chicken bowls

Original yield:

4

Original ingredients:

• Chicken 400 g
• Rice 240 g
• Broccoli 300 g

Scaling factor:

Scaled:

Chicken:

300 g

Rice:

180 g

Broccoli:

225 g

Recipe 2: Bean pasta

Original yield:

6

Original:

• Pasta 600 g
• Beans 3 cans
• Tomatoes 600 g
• Spinach 300 g

Scaling factor:

Scaled:

Pasta:

300 g

Beans:

1.5 cans

Tomatoes:

300 g

Spinach:

150 g

Recipe 3: Chicken tacos

Original yield:

4

Original:

• Chicken 500 g
• Tortillas 8
• Peppers 2
• Yogurt 200 g

Scaling factor:

Scaled:

Chicken:

375 g

Tortillas:

6

Peppers:

1.5

Yogurt:

150 g

Combine the example

Weekly totals:

Chicken

Rice

180 g

Broccoli

225 g

Pasta

300 g

Beans

1.5 cans

Tomatoes

300 g

Spinach

150 g

Tortillas

6

Peppers

1.5

Yogurt

150 g

Now check inventory.

Existing inventory

Chicken:

175 g

Rice:

250 g

Pasta:

100 g

Beans:

1 can

Tortillas:

2

Yogurt:

50 g

No broccoli, tomatoes, spinach, or peppers.

Actual grocery quantities

Chicken:

Rice:

Pasta:

Beans:

Tortillas:

Yogurt:

Plus:

Broccoli:

225 g

Tomatoes:

300 g

Spinach:

150 g

Peppers:

1.5

Now convert these to store packages.

Example package conversion

Beans are sold in whole cans.

Need:

0.5 can

Buy:

1

Remainder after the recipe:

0.5 can

Give it a destination, such as another lunch.

Tortillas:

Need:

4

Package:

8

Remainder:

4

Plan another wrap meal or store appropriately.

Peppers:

Need:

1.5

Buy:

2

Remaining half pepper can go into breakfast or lunch.

The arithmetic now informs the meal plan instead of leaving random ingredients behind.

A reusable recipe-to-grocery worksheet

Recipe:

Original servings: _

Portions needed now: _

Planned leftover portions: _

Planned freezer portions: _

Total portions needed: _

Scaling factor: _

Then combine identical ingredients.

Use this week:

Freeze:

Carry forward:

That is the full conversion from recipe servings to a grocery list.

The shortest method

If you want a compact formula, use:

1. Portion requirement

Current portions + planned leftovers

2. Recipe scale

Required portions ÷ recipe servings

3. Ingredient scale

Original ingredient × recipe scale

4. Grocery total

Add the same ingredient across every recipe

5. Net amount

Total requirement – inventory

6. Package amount

Round the net amount to purchasable package quantities

That six-step sequence handles most recipe-based grocery lists.

Common mistakes

Cooking the original recipe size automatically

Scale according to the portions you actually need.

Treating recipe servings as mandatory personal portions

Use your household’s real meal yield when it differs consistently.

Scaling each ingredient but forgetting leftovers

Add planned future portions before calculating the scaling factor.

Rounding ingredients before combining recipes

Combine first, then round.

Listing the same ingredient three times

Create one master ingredient total.

Forgetting breakfast and snacks

Add non-recipe uses after scaling your recipes.

Shopping before checking the pantry

EPA recommends checking the refrigerator, freezer, and pantry first.

Subtracting food already reserved for another meal

Count only genuinely available inventory.

Confusing Nutrition Facts servings with recipe servings

FDA notes that label serving sizes are standardized consumption references, not individualized recommendations.

Mixing grams, cups, pounds, and pieces without conversion

Standardize each ingredient before totaling.

Treating usable recipe quantity as purchase quantity when significant trimming is involved

USDA’s Food Buying Guide distinguishes food as purchased from edible or servable yield.

Choosing packages before calculating the true requirement

Calculate first, shop second.

Increasing portions merely to finish a package

Let the meal plan determine the food requirement.

Convert servings first, packages last

The cleanest way to calculate grocery quantities from recipes is to separate the process into two stages.

First calculate what the meals require.

For each recipe:

Then:

Do that for every recipe.

Next combine all repeated ingredients.

If chicken appears in three recipes, add all three chicken quantities.

If onions appear in five, add all five.

Then include breakfast, lunch, snacks, and other non-recipe uses.

Only after that should you check:

refrigerator

freezer

pantry

and subtract what you already own.

EPA recommends this meal-first, inventory-first approach as a way to buy only the food actually needed.

Finally, convert the remaining exact quantities into the packages your store sells.

That order matters:

Scale.

Combine.

Subtract.

Package.

Do not start with package sizes and force the meal plan to match them.

And do not round every recipe ingredient before seeing whether another recipe uses the same food.

Once you follow this sequence, a weekly plan containing several recipes stops producing a vague list such as:

chicken, vegetables, rice, yogurt

and becomes something much more useful:

Chicken: 850 g

Rice: already enough in pantry

Broccoli: 300 g

Yogurt: 700 g

That is the point of converting recipe servings into grocery quantities.

You know not only what to buy, but approximately how much you actually need.