Instant oatmeal is a quick cooking form of whole grain oats that has been coarsely chopped, precooked, flattened between metal rollers and dried. Instant oatmeal may be mixed with other dry ingredients such as powdered milk, sugar, or dehydrated fruit to create an easily reconstituted breakfast food. While traditional oatmeal may take 20 minutes or more to prepare, instant oatmeal can be table-ready in only two to three minutes.

There are some trade-offs to consider, however, when using instant oatmeal instead of the traditional oat varieties. The consistency of instant oatmeal can be noticeably thinner and creamier than whole oatmeal, which means it doesn't have the distinctive "bite" many oatmeal enthusiasts prefer. Because instant oatmeal has been precooked, it may also be lacking in some of the nutrients and fiber found in traditional oatmeal.

Traditional oatmeal takes a significant amount of time to cook because the entire grain must be penetrated by the water to soften it up. By grinding, flattening and precooking the whole oatmeal grain, instant oatmeal producers significantly reduce the amount of time needed for hot water to penetrate and reconstitute the processed oatmeal. The hot water can also rehydrate dried apples or other fruits, as well as liquefy the additional sweeteners and powdered milk.

Like many other instant or quick-cooking products, there is always a question about the taste compared to the traditional product. Instant oatmeal can suffer in side-by-side comparisons with long-cooked oatmeals, but a number of consumers find the savings in preparation time makes up for any shortcomings in flavor. This is one reason why manufacturers of instant oatmeal often create an entire array of enhancing flavors, from brown sugar to banana nut to fruit and spice combinations. Some manufacturers also offer a higher quality line of instant oatmeal with heartier grains and more complex flavors.

Many home cooks use a quick-cooking variety of oatmeal which is precooked but not ground or flattened like instant oatmeal. These "quick oats" do require some actual cooking time, since they are not designed to be reconstituted quickly in boiling water like individually packaged instant oatmeal. Some grocery stores may offer "instant oatmeal" in similar canisters to "quick oatmeal", so consumers should be aware of the difference. Traditional long-cooking oatmeals might also be stacked near their quick or instant oatmeal cousins, so it pays to read the label before buying oatmeal in a canister. Oatmeal products sold in individual packages almost always contain instant oatmeal, however.