Total Meals
20
Containers
20
Prep Time
300min
What is Meal Prep Calculator?
▾
Hey there! We've all been there: it's 6:00 PM on a hectic Tuesday, your stomach is growling, and the easiest option is to spend $20 on takeout. Again. That is where meal prepping comes in like a total lifesaver. By spending just a couple of hours on a Sunday chopping, roasting, and portioning, you set yourself up for a week of stress-free, healthy, and incredibly cheap eating. But here is the tricky part: how do you actually know how much raw chicken to buy at the grocery store so you end up with exactly five 150-gram cooked portions? If you just wing it, you either run out of food by Thursday or end up wasting expensive ingredients. That is exactly why we built the DigiCalcs Meal Prep Calculator. Think of it as your digital kitchen assistant that does all the annoying math for you before you even grab a shopping cart. You just tell it how many meals you want to make, who you are cooking for, and your target portion sizes. It immediately translates those cooked meal targets into a neat, raw grocery list. No more guessing games at the meat counter or staring blankly at a pile of raw sweet potatoes wondering if it is enough to get you through the week. Beyond saving you from mid-week grocery runs, using this tool helps you take control of your health and your wallet. Did you know that cooking at home usually costs about a third of what you would pay at a restaurant? By planning your meals and using our calculator to buy exactly what you need, you will slash your weekly food waste to near zero and keep your hard-earned money in your bank account. It is the ultimate hack for busy students, fitness lovers, and families who want to eat well without the daily headache of 'what's for dinner?'
DigiCalcs delivers precision-engineered tools for engineers and STEM professionals.
Formula
▾
Raw Protein Needed = Cooked Portions × Portion Size ÷ Yield Factor
Yield Factors: Chicken breast = 0.75, Ground beef = 0.80, Fish = 0.70
Total Calories per Batch = Portions × Target Calories per Meal
Container Count = Total Portions + 10% bufferVariable Legend
▾
| Symbol | Name | Unit | Description |
|---|---|---|---|
| YF | Yield Factor | decimal | This is the magic shrink-factor number! It represents how much weight your food loses when cooked. For example, chicken shrinks as water evaporates during baking, leaving you with about 75% of its raw weight. |
| P | Portions | count | The total number of individual, ready-to-eat meals you want to pack into your containers for the week. |
| PS | Portion Size | grams | The targeted weight of your cooked food (usually in grams or ounces) that you want in each individual meal prep container. |
How to Meal Prep Calculator
▾
- 1Step 1: Figure out your game plan by deciding how many days you are prepping for and how many meals you need each day.
- 2Step 2: Pick your favorite ingredients—choose a tasty protein, a comforting carb, and some colorful veggies to keep things balanced.
- 3Step 3: Input your desired cooked portion sizes into the calculator to let it work its magic.
- 4Step 4: Grab your calculated grocery list and head to the store, buying the exact raw weights suggested.
- 5Step 5: Fire up the stove! Cook your ingredients in big batches, then use a kitchen scale to divide them evenly into your containers.
- 6Step 6: Pop your meals for the first few days into the fridge, and freeze the rest so they stay super fresh for later in the week.
Worked Examples
▾
Let's do the quick math together! For your turkey, you need 5 portions of 120g cooked meat, which is 600g total cooked. Because turkey shrinks during cooking (yielding about 80% of its raw weight), we divide 600g by 0.80. This means you need to buy exactly 750g of raw ground turkey at the store.
To feed two people for four nights, you need 8 total portions. Each portion calls for 150g of cooked chicken breast, giving us a target of 1,200g of cooked meat. Since chicken breast has a yield factor of 0.75, we divide 1,200g by 0.75. Your grocery list target is 1,600g (or 1.6 kg) of raw chicken breast. For the rice, it triples in weight when cooked, so 8 portions of 120g cooked rice (960g total cooked) divided by 3 means you only need to boil 320g of dry rice!
Salmon has a yield factor of 0.70. For 4 meals, you need 480g of cooked salmon (120g x 4). Dividing 480g by 0.70 tells us to buy about 685g of raw salmon. For the rice, cooked white rice triples in weight (yield factor of 3.0), so if you want 120g cooked rice per meal (480g total cooked), you only need to boil 160g of dry rice!
You want to prep 12 quick taco portions for busy school nights, with 80g of cooked beef in each. That is 960g of cooked beef in total. Ground beef has a yield factor of 0.80 because of fat and moisture loss. Dividing 960g by 0.80 means you should pick up a 1.2 kg pack of raw ground beef.
Real-World Applications
▾
Busy parents use our calculator on Sunday mornings to plan out stress-free school lunches and quick weeknight dinners for the entire family.
Fitness enthusiasts and bodybuilders use it to precisely map out their daily macronutrient targets without spending hours doing manual kitchen math.
Budget-conscious college students use the tool to buy exactly what they need at the grocery store, avoiding wasted food and expensive mid-week takeout runs.
Personal chefs and meal delivery startups use these yield calculations to scale up their recipes and purchase bulk ingredients without running short.
Special Cases
▾
Super-shrunken meats or heavy marinades
In these situations, the standard yield factors might leave you a bit short on cooked protein. We recommend using a slightly lower yield factor (like 0.65) or buying an extra half-pound of meat as a safety buffer so you do not end up with empty containers at the end of your prep session.
Bone-in vs. boneless meats
Our calculator assumes you are working with boneless cuts. If you buy bone-in meats, you will need to increase your raw purchase weight by roughly 20% to 30% to account for the weight of the bones and skin that will get discarded after cooking.
Dehydrated foods that expand instead of shrinking
When prepping rice or lentils, remember that a little goes a long way. Since dry rice triples in weight, always divide your cooked target weight by 3 to find your dry starting weight. Don't accidentally cook 1 kg of dry rice unless you want to eat rice for a month!
Common Protein Yield Factors and Portioning
▾
| Protein Type | Shrinkage Yield Factor | 100g Raw Becomes... | Best Cooking Method | Fridge Freshness Window |
|---|---|---|---|---|
| Chicken Breast | 0.75 | 75g cooked | Baking or Grilling | 4 to 5 days |
| Chicken Thigh | 0.78 | 78g cooked | Roasting or Braising | 4 to 5 days |
| Ground Beef (Lean) | 0.80 | 80g cooked | Pan Searing | 4 days |
| Salmon Fillet | 0.70 | 70g cooked | Oven Baking | 3 to 4 days |
| Shrimp | 0.65 | 65g cooked | Quick Sautéing | 3 days |
| Hard-Boiled Eggs | 1.00 | 1 egg = ~50g | Boiling | 7 days (leave unpeeled) |
| Dry Lentils (dry to cooked) | 2.50 | 100g dry = 250g cooked | Simmering | 5 days |
Frequently Asked Questions
▾
Why does my cooked meat weigh so much less than the raw meat I bought?
Don't worry, you didn't get ripped off at the grocery store! When you cook meat, it naturally loses water weight and fat as it heats up. This shrinkage is called the 'yield factor' and usually ranges from 20% to 30% depending on the cut. Our calculator accounts for this so you always buy enough raw meat to hit your cooked targets.
How long can I actually keep my prepped meals in the fridge before they go bad?
As a general rule of thumb, most cooked meals will stay fresh and safe in the fridge for 3 to 4 days. If you are prepping for a full 5-day or 7-day week, we highly recommend keeping the first 3 days in the fridge and popping the rest in the freezer. Just pull a frozen meal out the night before you want to eat it so it can thaw safely in the fridge!
Can I freeze any meal prep, or are there some foods I shouldn't freeze?
While most meats, grains, and hearty stews freeze beautifully, some foods do not survive the freezer well at all. Vegetables with high water content, like cucumbers, lettuce, and raw tomatoes, will turn into mush when thawed. Dairy-based sauces can also separate and look curdled, so it is best to add those fresh right before eating.
What is the best way to reheat my prepped meals so they don't taste dry?
The secret to reheating without drying out your food is adding a splash of moisture! Sprinkle a teaspoon of water or broth over your food, cover it loosely with a damp paper towel, and microwave it in short 1-minute bursts. This creates steam that keeps your chicken juicy and your rice nice and fluffy instead of dry and crunchy.
Should I weigh my food raw or cooked when tracking my calories?
While weighing food raw is technically the most accurate method because cooking times and moisture loss can vary, weighing it cooked is much more practical for meal prepping. Since you are cooking in big batches, it is easiest to use our calculator to buy the right raw amount, cook it all up, and then weigh out your cooked portions. Just make sure you are tracking the cooked values in your fitness app!
Common Mistakes to Avoid
▾
- !Prepping a whole week of fish — seafood really only stays fresh and tasty in the fridge for 2 to 3 days max.
- !Putting hot food straight into the fridge, which traps steam, makes veggies soggy, and can unsafely warm up your fridge.
- !Forgetting that meat shrinks when cooked and buying the exact cooked weight in raw meat at the store.
- !Mixing wet sauces directly with crunchy greens, turning your Thursday salads into a soggy, unappealing mess.
- !Not labeling your containers, leaving you playing a risky game of 'guess how old this mystery chicken is' by Friday.
- !Choosing meals that taste terrible when reheated, like fried foods or delicate soft-boiled eggs, which ruins your motivation.
Pro Tip
Try 'component prepping' instead of fully assembling every single meal! Cook a big batch of seasoned chicken, roast a couple of different veggies, and make a pot of rice. Store them in separate large containers, then mix and match your plates throughout the week so you do not get bored of eating the exact same meal five days in a row.
Did you know?
Did you know that the average American household throws away about 30% of the food they buy? By spending just one hour meal prepping with a calculator, you can cut your personal food waste down to almost zero, saving hundreds of dollars a month while keeping good food out of landfills!
References
Get Weekly Math Tips
Join 12,000+ subscribers who get calculator tips every week.