You cook a big pot of soup. How many servings is that? How many calories per bowl? How long will it last in the fridge? These all come down to one calculation: total weight divided by serving size. Once you've got that, meal prep becomes systematic.
The basic yield math
Per-serving weight = total cooked weight ÷ number of servings.
Per-serving calories = total calories ÷ number of servings.
That's it. The challenge is getting the inputs right.
Estimating total weight
The most accurate method: weigh the empty pot, weigh the pot with cooked food, subtract. Many digital kitchen scales handle 5–10 kg — large enough for a big stew or roast.
If you can't weigh the whole pot, sum the ingredients before cooking and apply a moisture-loss correction:
- Soups, stews: ~5–10% loss to evaporation
- Roasts, baked goods: 15–25% loss
- Pasta, rice (cooked): these absorb water, so cooked weight is GREATER than ingredient weight
For exact portion control, weigh the cooked dish.
Standard serving sizes
| Food | Standard serving | Notes |
|---|---|---|
| Pasta (cooked) | 1 cup, ~140 g | ~2 oz dry per serving |
| Rice (cooked) | 3/4 cup, ~125 g | ~1/3 cup dry per serving |
| Cooked vegetables | 1 cup, ~150 g | 2 cups raw before cooking |
| Cooked meat | 3 oz, ~85 g | 4 oz raw before cooking |
| Soup, stew | 1.5–2 cups, 350–500 g | Main course portion |
| Casserole | 1 cup, ~250 g | Standard square cut from 9×13 |
| Salad (no dressing) | 2 cups, ~150 g | Side or starter |
Adjust by appetite — a hungry person eats 1.5–2× standard servings. A small eater eats 0.7×.
Meal prep: planning a week
For one person, 5 lunches and 5 dinners per week:
- 5 × 350 g lunches = 1750 g of "lunch food"
- 5 × 500 g dinners = 2500 g of "dinner food"
- Total: ~4.2 kg of cooked food per person per week (Mon–Fri)
This translates to roughly:
- 10 servings of protein (roughly 850 g cooked)
- 10 servings of carbs (~1250 g cooked rice/pasta/grains)
- 10 servings of vegetables (1500 g cooked + raw)
- Sauces, fats, condiments to taste
Container sizing
If you're packing meal prep into containers, popular sizes:
- 16 oz (475 ml): generous lunch portion
- 24 oz (700 ml): dinner-sized
- 32 oz (950 ml): double serving / family-style
Match container to portion. A 32-oz container with a 350 g lunch leaves a half-empty look that's psychologically less satisfying.
Calories per serving without exact ingredient tracking
Approximate calorie estimates by weight:
- Cooked rice: 130 kcal per 100 g
- Cooked pasta: 130 kcal per 100 g
- Cooked chicken breast: 165 kcal per 100 g
- Cooked ground beef (80/20): 250 kcal per 100 g
- Cooked salmon: 200 kcal per 100 g
- Olive oil: 880 kcal per 100 g (or 120 kcal per tablespoon)
- Mixed vegetables: 50–100 kcal per 100 g
- Cheese: 350–400 kcal per 100 g
For exact calorie tracking, use an app (MyFitnessPal, Cronometer) and weigh ingredients before cooking.
Storage limits
- Cooked meat: 3–4 days refrigerated. Freeze for longer.
- Cooked rice: 3–4 days. Reheat thoroughly to 165°F (food safety — rice can harbor B. cereus).
- Cooked vegetables: 3–5 days. Some get mushy faster (broccoli) than others (roasted root vegetables).
- Soups, stews: 3–4 days refrigerated. Freeze for 2–3 months.
Plan meal prep for 4 days max. Day 5 lunches should come from fresh-cooked food or frozen-and-thawed.
Doubling vs scaling up
For meal prep, doubling a recipe is straightforward (see our scaling guide). Going beyond 2× often requires switching to large pots and adjusting cooking time. A 4× soup recipe in a single 16-quart pot stays simple. A 4× casserole means two 9×13 pans baked simultaneously.
The "cook once, eat thrice" plan
Successful meal prep often layers recipes:
- Roast a big tray of chicken thighs (10 thighs, ~1.5 kg cooked).
- Cook a pot of brown rice (4 cups, ~700 g cooked).
- Roast vegetables (1 large sheet pan, ~1 kg cooked).
- Make a sauce or dressing.
- Combine in 8 containers across 4 different cuisines (taco, Mediterranean, Asian, Italian) by changing the sauce.
One cooking session, 8 distinct meals.
Calculate your batches
Our recipe yield calculator handles the math: enter total weight and number of servings, get per-serving size and calories. Useful for portioning meal-prep batches or calculating exact daily macros.