You will need
  • A piece of paper and pen
  • Calculator
  • Recipe book
Check invited, what food and drinks they prefer. Create a menu, avoiding the delicacies which love only some of your guests.
Rate the how many people are invited and how long your party. If you want to serve only snacks, multiply the duration of the party on the number of guests to eight. For example, you have invited 20 people and you assume that your party will last no more than 4 hours. So you will need a total of at least 640 appetizers (8х4х20). Checking the menu, divide this figure by the total number of snacks that you plan to file. Suppose you are going to cook two batches of eateries pies, tarts with salad and three kinds of sandwiches, therefore, each denomination, you need not less than 107 pieces. Now take a recipe and multiply the number of products on each of them so that you have 107 products. Make a list of products, grouped by category. So, for example, butter for sandwiches and pies don't need to write five times, and should just fold and get the total number of required oil. If you have a dinner, then snacks need exactly two times less.
Now let's calculate how much food you will need for hot dishes. Calculate the total amount of meat or fish products to the shelf on the man had from 180 to 240 grams. If you served on hot pasta as a main dish, it should be 240 grams per person, but if you plan it in as a garnish, expect no more than 100 grams per person. If you are preparing a risotto or paella, consider 180 gram per guest, if you serve rice as a side dish, aim for at 50 grams per serving. Serve on the side 120 grams of vegetables, 250 grams of potatoes and 60 grams of beans per person. For leafy salads, there is a norm of 30 grams per person, excluding sauce. For desserts, prepare at least 100 grams of ice cream and a piece of cake, cupcake or cake.

Repeat the same procedure as with the appetizers - focusing on designed you portions, make a grocery list for your planned meals.
Now it remains to find out how many liters of different drinks you may need. For soft drinks there is a norm of 4 liters per 10 people. Alcoholic beverages count as snacks, depending on the assumed duration of the party. So we multiply 20 guests for 4 hours, and now, since this is, after all, alcohol, multiply by 2, not 8 and get 160 servings of alcohol. If it's wine or a cocktail, but one serving is equal to 100 milliliters, if we are talking about alcoholic drinks, each serving of 30 grams.