Postcard of "Incorporating Salt and Working Moisture out of "Swift's Premium" Oleomargarine", undated

Consumers may choose margarine for a number of reasons, including lower cost, ease of availability, a perception (primarily relevant for vegetable-based margarines) that it is healthier than butter, a desire to avoid consuming animal-based products (of particular concern for vegans and also based on the assumption that the margarine is vegetable-based) and/or a simple personal preference to butter and/or other spreads on account of taste.

"A water-in-oil emulsion derived from vegetable/animal fats, with a fat content of at least 10% but less than 90%, that remain solid at a temperature of 20°C and are suitable as spread."

"To avoid any possible confusion, the Regulation limits the use of the terms "butter" and "margarine" to products with a fat content of not less than 80%."

Spread that contains 60 to 62% of fat may be called "three-quarter-fat margarine" or "reduced-fat margarine". Spread that contains 39 to 41% of fat may be called "half-fat margarine", "low-fat margarine", or "light margarine". Spreads with any other percentage of fat are called "fat spread" or "light spread".

Cudahy's Delrich brand of margarine used a "color berry" to color its white vegetable-based margarine yellow. This 1948 advertisement demonstrates how to color the margarine inside the package