Use this tag when you have a recipe that use a specific amount of ingredients but you need to make much more or just a little of the original recipe. Scaling normally needs technique.
There are a infinite number of recipes that you need to scale up or down.
In order to scale up or down the amount of each item in a recipe, you won't be able just to increase or decrease each ingredient to make more or less of the recipe. In those cases, there are some techniques that you will have to apply too!
Here are a few links to explain how scaling properly is important: