Meal Prep Portion Calculator

How this is calculated

THE PORTION COUNT IS THE EASY PART AND PEOPLE STILL GET IT WRONG, usually by forgetting that it multiplies three ways: people, meals a day, and days. Two people having one prepped meal a day for five days is ten portions, not five - and the shopping is built on the ten. ⚠️ RAW WEIGHT AND COOKED WEIGHT ARE NOT THE SAME NUMBER, AND THIS IS WHERE THE SHOPPING GOES WRONG. Meat loses water and fat in the pan and comes out lighter. Rice, pasta and pulses absorb water and come out very much heavier. So a portion size measured on a plate tells you almost nothing about how much to buy, and the error runs in OPPOSITE directions depending on the ingredient - buy too little meat and too much rice, in the same shop. ⚠️ THE YIELD IS AN INPUT BECAUSE IT DEPENDS ON YOUR COOKING. How much a piece of meat loses depends on the cut, the fat content and how hard and how long you cook it. How much rice gains depends on the variety and how much water it was given. Published figures for the same ingredient disagree, so this tool asks rather than assumes. THE WAY TO GET YOURS: weigh the ingredient raw, cook it exactly as you normally do, weigh it again, and divide the cooked weight by the raw weight. Do it once for the things you prep regularly and the figure is good for years. A yield of 100 means nothing changes. Below 100 the ingredient loses weight, so you buy MORE than the plate weight. Above 100 it gains, so you buy LESS. Rice and pasta sit well above 100; roasted meat sits below. ⚠️ HOW LONG COOKED FOOD KEEPS IS A FOOD SAFETY QUESTION AND THIS TOOL DOES NOT ANSWER IT. The fridge-days field is yours to set, and the authority is your national food safety agency rather than any calculator - the guidance is short, specific and freely published, and it differs a little between countries. What this tool does is arithmetic: given the number of days you are willing to keep it, it tells you how many portions that covers and how many therefore have to be frozen. FREEZE ON THE DAY YOU COOK, NOT ON THE LAST DAY IT LOOKS FINE. The portions that are going in the freezer should go in while they are fresh, not after several days in the fridge - freezing stops the clock, it does not turn it back. That is why this tool works out the freezer count up front, as part of the plan, rather than leaving it as something you discover on Wednesday. THE PORTION SIZE IS COOKED WEIGHT ON THE PLATE, all components together. If you would rather work component by component - protein, starch and vegetables separately, each with its own yield - run the tool once per component and add the shopping up. That is more accurate for a mixed meal, because the yields genuinely differ.

Common questions

Why is my portion count higher than I expected?

Because it multiplies three ways rather than two. Two people, one prepped meal a day, five days is ten portions - not five. The days figure is the one people anchor on, and the number of people and the number of meals each are silently folded in. It matters because everything downstream is built on the portion count: the shopping, the container count, the pot you need and how much of it will not fit in the fridge.

Why doesn't the plate weight tell me what to buy?

Because cooking changes the weight, and it changes it in opposite directions depending on the ingredient. Meat loses water and fat in the pan and comes out lighter, so you have to buy more than the plate weight. Rice, pasta and pulses absorb water and come out much heavier, so you buy considerably less. Shopping from the plate weight means under-buying the meat and over-buying the starch in the same trip, which is why a meal-prep session so often runs out of one thing while producing far too much of another.

How do I find my own yield figure?

Weigh the ingredient raw, cook it exactly the way you normally would, and weigh it again. Cooked weight divided by raw weight, times a hundred, is the number to enter. Published figures for the same ingredient disagree with each other because the answer depends on the cut, the fat content, the variety and how hard you cook it - so measuring beats looking it up. Doing it once for the four or five things you prep regularly takes almost no extra effort, since you are cooking them anyway.

What does a yield above 100 mean?

That the ingredient gains weight during cooking, which is normal for anything that absorbs water - rice, pasta, pulses, grains. A yield of 300 means the cooked weight is three times the raw weight, so a 180 g cooked portion started life as 60 g. Below 100 means the opposite: the ingredient loses weight, and you have to buy more than the plate weight to end up with it. Exactly 100 means nothing changes, which is roughly true of a mixed meal where the losses and gains cancel out.

How long does cooked food actually keep?

That is a food safety question, and the honest answer is that this tool should not be the one giving it to you. Your national food safety agency publishes short, specific and freely available guidance, it is the authority, and it differs a little between countries. The fridge-days field is there for you to enter the figure you are working to. What the tool does is the arithmetic that follows from it: how many portions that window covers, and how many therefore need to go in the freezer instead.

Why freeze on the day I cook rather than later?

Because freezing stops the clock, it does not turn it back. A portion that has sat in the fridge for three days and is then frozen comes out of the freezer as a portion that has already used most of its life. If part of the batch was always going to be eaten later, it should go into the freezer while it is fresh - which means deciding the split before you start rather than discovering it midweek. That is exactly why this tool reports the freezer count up front as part of the plan.

Should I do this per ingredient instead?

For a mixed meal, yes, and it will be more accurate - the yields genuinely differ, and a single blended figure for a plate of chicken, rice and vegetables is an average of three quite different numbers. Run the tool once per component with that component's cooked portion size and its own yield, then add the shopping figures. The portion count stays the same across all of them, so only the weights change. For a one-pot meal a single run is fine.

Take it further with AI

Copy this into ChatGPT or Claude with your own numbers filled in. It hands over the figures this calculator worked out, so the answer is built on real arithmetic instead of a guess.

I used the Meal Prep Portion Calculator at https://www.bfcbrilliance.com/tools/meal-prep-portion-calculator.

What I entered:
- People eating (people): ___
- Prepped meals per person per day (meals): ___
- Days to cover (days): ___
- Portion size, cooked (g): ___
- Cooked weight as a share of raw (%): ___
- Days you will eat from the fridge (days): ___

What it calculated:
- Portions to make: ___
- Portions for the fridge: ___
- Portions to freeze on cooking day: ___
- Total cooked weight: ___
- Raw food to buy: ___

Use those figures as given — they are already worked out, so please don't recalculate or estimate your own. Help me turn them into a plan: what to buy or do, in what order, roughly what it should cost, and the mistakes people most often make with this job.

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